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059149949	summary	BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The invention relates to a storage basket having a plurality of inserts for receiving a fuel element of a nuclear power plant. The invention also relates to a fuel element storage rack for the compact storage of fuel elements, including a carrying structure for carrying the fuel elements and a storage basket having a plurality of inserts for receiving a fuel element. The invention furthermore relates to a method for the storage of fuel elements and control rods of a nuclear power plant. In nuclear power plants for generating electrical energy from fissionable material, the fissionable material is inserted in so-called fuel elements. While the nuclear power plant is operating, the fissionable material in the fuel elements is split as a result of a nuclear chain reaction. After the fissionable material has been largely consumed, that is to say spent, the spent fuel elements are intermediately stored in so-called water-filled storage basins. Fuel element storage racks are provided for receiving the fuel elements in the storage basins. German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 describes a storage rack for fuel elements of a nuclear power plant, in which a plurality of wells having an essentially rectangular cross section are fastened on a base plate. The wells stand upright on the base plate and in each case are disposed diagonally opposite one another in a checkered manner. Some of the wells located diagonally opposite one another are connected to one another along mutually contiguous longitudinal edges through the use of at least two connecting elements. A first connecting element has high rigidity in a first direction which runs parallel to the base plate. A second connecting element likewise has high rigidity in a second direction which likewise runs parallel to the base plate. An angle between the first direction and the second direction is between 70.degree. and 90.degree.. The wells are connected to one another through the connecting elements in a mechanically stable manner, with high carrying capacity, in such a way as to form a unit. The walls of the wells serve as an absorption device for neutron radiation and are composed of an austenitic boron steel with a boron content of up to 2%. The fuel element storage rack described in German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 allows a compact storage of fuel elements, wherein a fuel element is capable of being stored both in each well and in cavities formed between the wells. The fuel elements and the wells are extended along a main axis in each case, with the main axes running essentially parallel to one another. In that case, the main axes are essentially perpendicular on the base plate of the storage rack. U.S. Pat. No. 4,960,560 describes a storage rack for fuel elements of a boiling water nuclear power plant. The storage rack has a rectangular base plate which rests on feet. A multiplicity of wells, each for receiving a fuel element, is disposed on the base plate. The wells are extended along a main axis which is perpendicular on the base plate. The wells are disposed on the base plate in a checkered manner, with the wells being welded to one another over their entire height along the outer edge of the base plate through the use of metal sheets, so that a continuous closed outer wall is formed. Circular orifices are present in the bottom of the base plate in each well. Moreover, some of the orifices have depressions differing from the circular shape, so that a lifting appliance which is introduced through them, after it has been rotated by a few degrees, can no longer be led through the orifice. As a result, an anchorage of the lifting appliance is provided, in a similar way to the lid of a teapot, and the possibility of lifting the base plate is thereby afforded. Both German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 and U.S. Pat. No. 4,960,560 relate merely to the compact storage of fuel elements. Neither of the two publications deals with the problem of storing other spent or irradiated core components, in particular control elements and control rods of a boiling water nuclear power plant. SUMMARY OF THE INVENTION It is accordingly an object of the invention to provide a storage basket and a storage rack for the compact storage of fuel elements and control rods and a method for the storage of fuel elements and control rods of a nuclear power plant, in particular a boiling water nuclear power plant, which overcome the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type. With the foregoing and other objects in view there is provided, in accordance with the invention, a storage basket, comprising a plurality of inserts for receiving a fuel element of a nuclear power plant, the inserts defining a cruciform gap for receiving a control rod (control element). By virtue of the formation of a cruciform gap between the inserts, the inserts can be slipped over a control rod which has a corresponding cruciform cross section. The control rod and the inserts are extended along a respective main axis. The main axes run essentially parallel to one another. The inserts are disposed appropriately according to the cross-sectional shape of the control rod. In this case, the control rod may have a cross section in the form of a simple cross, in each case with four wings of equal length which are perpendicular to one another. However, the wings may also be of different length and may not be orthogonal to one another. The number of wings may also be different from four. Both the control elements and the fuel elements can be stored intermediately in a space-saving manner through the use of this configuration of inserts for receiving a fuel element. There is therefore no need for a separate storage rack or special suspension devices on the walls of the storage basin above the storage racks for fuel elements. The length of the inserts depends on the length of the fuel elements to be received. The region of the fuel elements which is exposed to radioactive radiation is enclosed by the respective insert for absorption purposes. The insert forms an absorber well having a wall made preferably of austenitic boron steel. The position of the insert relative to the control element depends, in particular, on the shape of the control element. In the case of a dish-shaped foot part of the control element the insert is disposed geodetically above the foot part. In the case of a cruciform foot part, the insert may also extend over this foot part. The insert and therefore the storage basket project with a lifting device beyond the control element. The storage basket may thereby be slipped over the control element and lifted off therefrom again in a simple way. In accordance with another feature of the invention, the inserts have a rectangular, in particular quadratic, cross-sectional area and extend along a main axis in a direction perpendicular to the cross-sectional area. As a result, particularly in the case of a cruciform control rod having wings that are orthogonal to one another, a particularly good utilization of space is achieved. A configuration composed of a control rod and a storage basket thus has an essentially rectangular, in particular quadratic cross-sectional area. The control rod and the storage basket can thereby be introduced into a carrying well of a storage rack in a particularly simple and space-saving way. In accordance with a further feature of the invention, the plurality of inserts includes four inserts, which may be disposed in each quadrant of a simple cross. Each control rod may thus be surrounded directly by four fuel elements. In accordance with an added feature of the invention, adjacent inserts are fixedly connected to form a unit, preferably through the use of at least one connecting element in each case. One or more connecting sheets are suitable as a connecting element. The connecting element or connecting elements are welded to the outer wall of adjacent inserts. In this case, adjacent inserts may be connected over the entire height of the outer wall or else only in a punctiform manner, that is to say over particular outer wall regions. The inserts which are thus connected to one another form a storage basket as a unit, which is capable of being slipped as a whole over a control rod. The storage basket preferably performs a pure storage function, that is to say it is slipped, in the non-loaded state, over the control element and is only subsequently loaded with fuel elements. Before the storage basket is lifted off from the control element, all of the fuel elements are first extracted from the storage basket again. The storage basket may, if appropriate, also be constructed as a transport container, so that when loaded with fuel elements, it can be slipped over the control element and can be lifted off therefrom again. Fuel elements can thereby be transported in a fuel element storage basin without any transloading. In accordance with an additional feature of the invention, the inserts are connected to a supporting element for enclosing a foot part of the control rod and for supporting them on a carrying structure of a fuel element storage rack. In this case, the supporting element may be constructed as a tube having a round or rectangular cross section, with the cross-sectional area of the supporting element covering the greatest cross-sectional area of the foot part. In accordance with yet another feature of the invention, the supporting element has a device for fastening the inserts, so that, in particular, they are secured against rotation. The supporting tube ensures that the lower edges of the fuel elements are located above the foot piece of a respective associated control element. The supporting element is itself secured against rotation. In accordance with yet a further feature of the invention, the inserts are fastened, in particular welded, to a base plate which likewise has a cruciform gap sufficiently large to slip the base plate over a corresponding control rod. In order to make it easier for the base plate and the inserts to be slipped over the control rod, the cruciform gap tapers over the thickness of the base plate towards the inserts. As a result, the storage basket, when being slipped over the control element, is centered by the latter and, consequently, the lowering of the storage basket along the main axis of the control element is markedly simplified. In accordance with yet an added feature of the invention, in order to secure the inserts against rotation, a cruciform reinforcing element adapted to the cruciform gap is disposed at the upper end of the inserts. The reinforcing element secures the inserts, which may be constructed as square tubes, and supports them. In accordance with yet an additional feature of the invention, the reinforcing element may have a device for lifting and transporting the storage basket. It may have at least one hook or transport bracket or it may be constructed as such. A gripping appliance may engage on the device, so that the storage basket can be transported in a fuel element storage basin and, in particular, can be inserted into a storage rack and extracted again. In accordance with again another feature of the invention, the storage basket has a releasable locking element for securing the inserts against being lifted unintentionally. The locking element may be a drop latch which is rotatable about a center of rotation and which swings down due to its own weight in the cruciform gap, so that after the storage basket has been slipped over the control rod, the drop latch comes to rest below a projection of a carrying well. If the storage basket is lifted unintentionally, for example when a fuel element is extracted from an insert, the drop latch is pressed against the projection (holding-down device) and a further upward movement of the storage basket is thereby prevented. The locking element can be released through the use of an appropriately shaped gripping appliance capable of being introduced into the cruciform gap. In particular, a drop latch can be swung upward and therefore the storage basket can be lifted from the control element and out of the carrying well. With the objects of the invention in view there is also provided a fuel element storage rack for the compact storage of fuel elements and control rods of a nuclear power plant, in particular of a boiling water nuclear power plant, comprising a carrying structure for carrying fuel elements and control rods; and a storage basket having a plurality of inserts for receiving a fuel element, the inserts defining a cruciform gap for receiving a control rod. In accordance with another feature of the invention, there are provided carrying wells on the carrying structure for receiving a control rod and a storage basket. The carrying wells may, in this case, be disposed in the same way as in German Published, Non-Prosecuted Patent Application DE 41 34 246 A1 and may be connected to one another through the connecting elements specified therein. The storage rack may therefore make use of the advantageous properties of the storage rack described in German Published, Non-Prosecuted Patent Application DE 41 34 246 A1. Above all, a mechanically extremely stable structure of the storage rack is achieved through the use of the connecting elements, without an additional composite carrying system being required at the geodetically upper end of the wells. In this case, the control element and the storage basket may both be inserted in each carrying well and in the intermediate positions between the carrying wells that are disposed in a checkered manner. The storage basket and the storage rack are preferably suitable for the compact intermediate storage of fuel elements and control elements of a boiling water nuclear power plant. With the objects of the invention in view there is additionally provided a method for the storage of fuel elements and control rods of a nuclear power plant, which comprises placing carrying wells on a carrying structure in a fuel element storage rack; and introducing both a control rod and at least one fuel element, preferably four fuel elements, in a respective one of the carrying wells. In accordance with a concomitant mode of the invention, there is provided a checkered configuration of the carrying wells that forms interspaces, in which both a control rod and a fuel element are likewise disposed in each case. A particularly compact storage of control rods and fuel elements is achieved thereby, with the result that the number of storable fuel elements can be markedly increased in comparison with a separate storage of control rods. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a storage basket and a storage rack for the compact storage of fuel elements and control rods and a method for the storage of fuel elements and control rods of a nuclear power plant, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
051280930	description	MODE(S) FOR CARRYING OUT THE INVENTION Illustrated in FIG. 1 is an exemplary boiling water nuclear reactor 10 having a reactor core 12 in which are disposed a plurality of conventional control rods 14, only one of which is illustrated. Each of the control rods 14 is selectively inserted into the core 12 and withdrawn from the core 12 by a conventional control rod drive (CRD) 16, with a plurality of CRDs 16 being provided for moving a respective plurality of control rods 14. Each of the CRDs 16 in this exemplary embodiment includes a conventional output shaft and piston 18 provided for quickly inserting the control rod 14 into the core 12 during a scram operation. More specifically, a hydraulic control system 20 in accordance with one embodiment of the invention is provided for the CRDs 16 to selectively deliver a scram fluid 22a at a relatively high scram pressure P.sub.s to the CRDs -6 during a scram operation for lifting the shaft and piston 18 to insert the control rod 14 into the core 12. During normal operation of the reactor 10, a purge fluid 22b at a relatively low purge pressure P.sub.p is continuously provided to the CRDs 16, for example to a conventional fine motion control rod drive (not shown) contained in each of the CRDs 16. The purge fluid 22b is conventionally discharged from the CRDs 16 into the reactor 10 having a reactor vessel internal pressure P.sub.r of about 73 kg/cm.sup.2 g in one embodiment. The purge fluid pressure P.sub.p is suitably greater than the reactor pressure P.sub.r, and may be, for example, about 80 kg/cm.sup.2 g to ensure its flow into the reactor 10 through the CRDs 16. And, the scram fluid pressure P.sub.s is at least about 130 kg/cm.sup.2 g in this exemplary embodiment. The scram and purge fluids 22a and 22b are provided from a common, conventional control rod drive (CRD) pump 24 through parallel charging and purge lines, or conduits, 26 and 28, respectively, disposed in flow communication between the CRD pump 24 and each of the CRDs 16. The CRD pump 24 is operable at a relatively high speed for providing a pressurized fluid 22 at a relatively high charging pressure P.sub.c for example, about 156 kg/cm.sup.2 g, with the pressurized fluid 22 being water, such as demineralized water provided from a conventional reservoir 32. The pressurized water 22 is discharged from the CRD pump 24 with a first portion thereof being channeled through the charging line 26 as the scram fluid or water 22a, and a second portion thereof being channeled through the purge line 28 as the purge fluid or water 22b. The charging line 26 includes in series flow communication from the CRD pump 24 to a conventional charging water header 34, a conventional check valve 36 and a conventional isolation valve 38. The check valve 36 is effective for checking, or preventing, backflow of the scram water 22a upstream in the charging line 26, and the isolation valve 38 is preferably normally closed for preventing flow of the scram water 22a into the header 34 or out of the header 34 by backflow through the isolation valve 38, which is also operable in an open position for allowing unrestricted flow of the scram water 22a into the header 34. The header 34 is disposed downstream of the isolation valve 38, and the charging line 26 includes a plurality of branches 26a extending downstream from the header 34 and disposed in parallel flow communication between the header 34 and respective ones of the CRDs 16. A plurality of conventional hydraulic control units (HCUs) 40 are disposed in parallel flow communication between the header 34 and respective ones of the CRDs 16, with each of the HCUs 40 being disposed in series flow communication in a respective one of the charging line branches 26a. Each of the HCUs 40 includes in series flow in the charging line 26, i.e. respective charging line branch 26a, an HCU check valve 42 and a preferably normally closed scram valve 44. The HCU 40 also includes a conventional scram accumulator 46 disposed in flow communication in the charging line 26 between the check valve 42 and the scram valve 44 for accumulating the scram water 22a at the charging pressure P.sub.c, with the check valve 42 being effective for checking backflow of the scram water 22a upstream toward the isolation valve 38. The purge line 28 includes a conventional, selectively operable flow control valve 48 in flow communication with the CRD pump 24 and a conventional purge water header 50 disposed in flow communication downstream therefrom. The purge line 28 also includes a plurality of branches 28a disposed in parallel flow communication between the purge water header 50 and respective ones of the CRDs 16 for channeling the purge water 22b thereto. Each of the purge line branches 28a preferably includes a conventional check valve 52 which checks, or prevents, backflow of the purge water 22b upstream in the branch 28a, and forms a component of the HCU 40. In a conventional hydraulic system for providing the pressurized water 20 to the CRDs 16, the CRD pump 24 is conventionally run continuously at its high speed to provide the pressurized water 20 at the relatively high charging pressure P.sub.c of about 156 kg/cm.sup.2 g which flows through the charging lines 26 to continuously charge the scram accumulators 46. The CRD pump 24 is operatively connected to a conventional electrical motor 54, which in one embodiment is a relatively high power motor effective for providing about 500 shaft horsepower for powering the CRD pump 24 for maintaining the charging pressure P.sub.c and for providing a maximum volume flow rate of about 506 l/min, for example. However, the charging pressure P.sub.c, e.g. 156 kg/cm.sup.2 g, is substantially greater than the purge pressure P.sub.p, e.g. 80 kg/cm.sup.2 g, required of the purge water 22b in the purge line 28, which flows at a reduced volume flow rate of about 267 l/min. Accordingly, in order to reduce the amount of electrical power required of the motor 54 for running the CRD pump 24 during normal operation of the reactor 10, and reduce operating costs, the hydraulic control system 20 in accordance with one embodiment of the present invention includes a conventional adjustable speed drive (ASD) 56 operatively connected to the motor 54 and a conventional control means, or controller 58. The ASD 56 is effective for controlling the speed of the motor 54 and the CRD pump 24 joined thereto so that the CRD pump 24 may operate as a variable output-pressure pump. Upon command from the controller 58, the ASD 56 is effective for operating the motor 54 and the CRD pump 24 at a first, relatively low, speed in a normal mode of operation for obtaining from the CRD pump 24 the pressurized water 22 at the relatively low purge pressure P.sub.p, which is channeled through the purge lines 28 as the purge water 22b to the CRDs 16. The ASD 56 is also responsive to the controller 58 for operating the motor 54 and the CRD pump 24 at its high, second speed, greater than the first speed, in a charging mode of operation for discharging from the CRD pump 24 the pressurized water 22 at the charging pressure P.sub.c which is channeled through the charging lines 26 to charge the scram accumulators 46. In this way, the CRD pump 24 may be more economically run for a substantial amount of time in the low speed, low pressure, normal mode for providing the pressurized fluid 22 at only the relatively low purge pressure P.sub.p which is channeled through the purge lines 28. The flow control valve 48 in the purge line 28 upstream of the purge water header 50 may control flow of the purge water 22b therethrough without appreciable pressure reduction in the normal mode. Although the HCU check valve 42 in each of the charging line branches 26a checks backflow of the scram water 22a therethrough, over time the scram water 22a will leak from the charging line 26, through the HCU check valve 42 for example, thusly reducing the pressure of the scram water 22a contained in the scram accumulator 46. When the pressure in the scram accumulator 46 decreases to a predetermined minimum scram pressure P.sub.m, the controller 58 signals the ASD 56 to operate the motor 54 and the CRD pump 24 at the high speed for recharging the HCU accumulators 46. The isolation valve 38 in a conventional hydraulic system would be normally open to allow flow of the scram water 22a to continuously charge the scram accumulators 46. However, in a preferred embodiment of the present invention, the isolation valve 38 is normally closed in the normal mode of operation for reducing leakage of the scram water 22a upstream in the charging line 26 from the HCU check valve 42 for delaying the leaking discharge of the scram accumulators 46 and delaying the need for operating the CRD pump 24 at its high speed. In order to further delay the need for recharging the scram accumulators 46, pressurizing means 60 in the exemplary form of a conventional accumulator are disposed in flow communication with the charging line 26 downstream of the isolation valve 38 and upstream of the scram valve 44, and preferably upstream of the charging water header 34 for providing pressurized makeup water 62. The makeup accumulator 60 is sized for maintaining the scram water 22a at a scram pressure P.sub.s which is greater than the minimum scram pressure P.sub.m, for example about 130 kg/cm.sup.2 g, and up to the charging pressure P.sub.c, e.g. 156 kg/cm.sup.2 g, when the CRD pump 24 is in the normal mode, or operating at low speed. Since the scram accumulators 46 are relatively low volume and since the charging line 26 including its branches 26a also are relatively low volume conduits, relatively little leakage of the scram water 22a therefrom will relatively quickly decrease the pressure inside the scram accumulators 46. Accordingly, the makeup accumulator 60 is predeterminedly sized for accumulating a portion of the scram water 22a as the makeup water 62 at the charging pressure P.sub.c in the charging mode, which makeup water 62 is then channeled back into the charging line 26 during the normal mode to offset leakage of the scram water 22a from the charging line 26 which decreases the pressure therein. More specifically, in the charging mode, the controller 58 is effective for opening the isolation valve 38 while the scram valves 44 are closed and operating the CRD pump 24 in the charging mode for providing into the charging line 26 the pressurized water 22 at the charging pressure P.sub.c to charge both the makeup accumulator 60 through the open isolation valve 38 and the scram accumulators 46 through the HCU check valves 42. The purge water 22b is also channeled from the CRD pump 24 and through the purge line 28 to the CRDs 16. The flow control valve 48 is suitably partially closed in response to a conventional system flow meter 48b for dropping the pressure across the flow control valve 48 from the charging pressure P.sub.c to the purge pressure P.sub.p. When the scram accumulators 46 and the makeup accumulator 60 are fully charged to the charging pressure in the charging mode, the controller 58 is effective for closing the isolation valve 38 while the scram valves 44 remain closed and operating the CRD pump 24 in the normal, reduced speed and pressure, mode for providing into the purge line 28 the pressurized water 22 at the reduced purge pressure P.sub.p. In the normal mode, the flow control valve 48 is near fully opened in response to the flow meter 48b for providing a minimum pressure drop thereacross. In the event of a scram mode of operation, the scram valves 44 are opened in response to signals from their conventional control system to allow the scram water 22a stored in the scram accumulators 46 to enter the respective CRDs 16 for fully inserting the control rods 14 into the core 12. In order to appropriately operate the control system 20 in the charging mode and in the normal mode, a conventional pressure sensor 64 is operatively connected to the charging line 26, preferably at the charging water header 34, and to the controller 58, and is responsive to the scram pressure P.sub.s of the scram water 22a in the header 34. When the controller 58 senses through the pressure sensor 64 that the scram pressure P.sub.s in the header 34 drops to the minimum scram pressure P.sub.m, the system 20 is operated in the charging mode for recharging the makeup accumulator 60 and the scram accumulators 46. When the controller 58 through the pressure sensor 64 determines that the scram pressure P.sub.s in the header 34 is substantially equal to the charging pressure P.sub.c, the system 20 is returned from the charging mode and to the normal mode. The pressure sensor 64 may be in the form of conventional pressure switches which are configured for suitably opening and closing at the minimum scram pressure P.sub.m and the charging pressure P.sub.c for correspondingly providing signals to the controller 58 for operating the system 20 in either of the normal mode or the charging mode. Alternatively, the pressure of the scram water 22a in the header 34 may be obtained through a conventional rod control and information system (RCIS) indicated schematically at 66 which provides low pressure setpoint signals used for blocking withdrawal movement of the control rod 14 when the pressure in the charging water header 34 is relatively low, at which low pressure, scram insertion of the control rod 14 is conventionally effected. The minimum scram pressure P.sub.m is preferably larger than the low pressure scram setpoint to allow the system 20 to charge the accumulators 60 and 46 without prematurely effecting scram. An exemplary minimum scram pressure P.sub.m is about 130 kg/cm.sup.2 g which is less than the charging pressure P.sub.c of about 156 kg/cm.sup.2 g for the exemplary CRD pump 24. Accordingly, the difference between these two pressures represents an acceptable pressure range for the scram pressure P.sub.s during which the system 20 may be operated in the normal mode. As described above, the makeup accumulator 60 may be suitably sized for delaying the drop of the scram pressure P.sub.s within this range to the minimum scram pressure P.sub.m which, y embodiment, may be about a week. Accordingly, the system 20 may be operated in the normal mode for about a week at a time, thusly reducing the expenditure of energy which would otherwise be required by operating the CRD pump 24 at its maximum speed and charging pressure P.sub.c in the charging mode, which reduces cost. The charging mode, accordingly, would occur about weekly for relatively short time periods to recharge the accumulators 60 and 46. Furthermore, continuous operation of the motor 54 and the CRD pump 54 at the reduced speed during the normal mode will produce less wear thereon, and therefore, reduced maintenance costs therefor. Upon initial startup of the reactor 10, the CRD pump 24 would be run at its high speed with the isolation valve 38 open to allow charging of the accumulators 60 and 46. When they are fully charged, the isolation valve 38 may be closed and the speed of the CRD pump 24 reduced to its long term operating speed in the normal mode. During subsequent operation, recharging of the accumulators 60 and 46 will occur automatically by the controller 58, or, the operator of the reactor 10 may monitor the pressure from the pressure sensor 64 to manually signal opening of the isolation valve 38 and increasing the speed of the CRD pump 24 in the charging mode for recharging the accumulators. Illustrated in FIG. 2 is an alternate embodiment of the pressurizing means 60 in the form of a conventional high pressure, low volume makeup pump 60a. The makeup pump 60a is conventionally operatively connected to the reservoir 32 for providing the makeup water 62 from the reservoir 32 into the charging line 26 during the normal mode to offset leakage of the scram water 22a therefrom. The makeup pump 60a may be predeterminedly sized substantially smaller than the CRD pump 24, for example having a driving motor thereof producing about 10 shaft horsepower. The makeup pump 60a is effective for providing the makeup water 62 into the charging line 26 downstream of the isolation valve 38 and upstream of the scram valves 44 into the header 34 at a relatively high pressure such as the charging pressure P.sub.c for offsetting leakage of the scram water 22a from the charging line 26 which would reduce the pressure in the scram accumulators 46. The size of the makeup pump 60a may be selected for matching the actual leakage from the charging line 26 to prevent the reduction of pressure of the charged accumulators 46. However, it is desirable to have a makeup pump 60a as small as possible for reducing the consumption of power for reducing costs. The makeup pump 60a will preferably operate continuously, and will be sized to allow the CRD pump 24 to run at its reduced speed mode for all normal operating conditions. Preferably, the CRD pump 24 would only have to be run at its high speed mode following a scram in order to recharge the accumulators 46. In either embodiment of the invention, an overall reduction in power consumption is obtained by operating the CRD pump 24 intermittently at its high speed and high discharge charging pressure P.sub.c. While there have been described herein what are considered to be preferred embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein, and it is, therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention.
	claims	1. An electron-beam size measuring apparatus comprising:electron beam irradiating means that irradiates an electron beam on a surface of a sample;detection means that detects electrons emitted from the sample;distance measurement means that measures the distance between the sample and a secondary electron control electrode of the detection means;a stage on which the sample is mounted; andcontrol means which adjusts the height of the stage so that the distance measured by the distance measurement means would be equal to a predetermined fixed distance, which applies a control voltage to the secondary electron control electrode of the detection means, the control voltage predetermined so as to allow the sample surface potential to become constant level when the sample is positioned at the fixed distance, and which causes the electron beam to be irradiated by applying a predetermined accelerating voltage. 2. The electron-beam size measuring apparatus according to claim 1, wherein the control voltage is a voltage at a time when a first measured value and a second measured value are equal to each other, the first measured value obtained by measuring a dimension of a calibration sample with the surface thereof not charged, the calibration sample made of the same material as that of the sample, and the second measured value being a value at a time when the measured value of the calibration sample does not vary any more, while the calibration sample is irradiated with the electron beam and is measured in dimension, alternately, from a state in which the surface of the calibration sample is charged at the beginning. 3. The electron-beam size measuring apparatus according to claim 1, wherein the stage includes holding means that does not electrically connect the sample thereto, and moving means that moves the sample up and down. 4. The electron-beam size measuring apparatus according to claim 1, wherein the control means causes the electron beam irradiating means to irradiate the entire surface of the sample with the electron beam. 5. The electron-beam size measuring apparatus according to claim 1, wherein the control means causes the electron beam irradiating means to irradiate, with the electron beam, an area to which a conductor on the sample is exposed. 6. The electron-beam size measuring apparatus according to claim 1, wherein the control means causes the electron beam irradiating means to adjust an electron irradiation amount of the electron beam to be larger than an irradiation amount of electrons at a time of measuring a dimension. 7. The electron-beam size measuring apparatus according to claim 1, wherein the control means measures a dimension of the sample after adjusting the potential of the surface of the sample to a fixed level. 8. A size measuring method with electron beams comprising the steps of:figuring out a control voltage to be applied to a secondary electron control electrode for adjusting the charge potential of the sample to become constant when the distance between a sample and the secondary electron control electrode is kept fixed, and also when an accelerating voltage for an electron beam to be irradiated on the sample is set to a predetermined value;adjusting the distance between the sample and the secondary electron control electrode to be the predetermined distance;irradiating the sample with an electron beam at the accelerating voltage by applying the control voltage to the secondary electron control electrode; andmeasuring a dimension of the sample after irradiating the electron beam. 9. The size measuring method with electron beams according to claim 8, wherein the control voltage is a voltage at a time when a first measured value and a second measured value are equal to each other, the first measured value obtained by measuring a dimension of a calibration sample with the surface thereof not charged, the calibration sample made of the same material as that of the sample, and the second measured value being a value at a time when the measured value of the calibration sample does not vary any more, while the calibration sample is irradiated with the electron beam and is measured in dimension, alternately, from a state in which the surface of the calibration sample is charged at the beginning. 10. The size measuring method with electron beams according to claim 8, wherein the electron beam is irradiated on the entire surface of the sample. 11. The size measuring method with electron beams according to claim 8, wherein the electron beam is irradiated on an area to which a conductor on the sample is exposed. 12. The size measuring method with electron beams according to claim 8, wherein an electron irradiation amount of the electron beam is larger than an irradiation amount of electrons at a time of measuring a dimension.
060268980	summary	FIELD OF INVENTION The within invention relates to a tubing head designed to accommodate a tubing rotator therein such that the tubing head may be retrofit with the tubing rotator. Further, the within invention relates to an apparatus for attachment to a wellhead for suspending and rotating a tubing string within a wellbore, the apparatus comprising a tubing head and a tubing rotator combined to form a single, integral unit. BACKGROUND ART A typical wellhead is often comprised of a casing head or a casing bowl which engages or is otherwise mounted to a casing string contained within a wellbore of a well at the surface. A tubing head or tubing bowl is mounted upon the upper surface of the casing head and provides a support mechanism for a tubing hanger. The tubing hanger is connected to or engages the upper end of the tubing string which is contained within the wellbore. Thus, the tubing hanger and the tubing string connected thereto are supported at the surface of the well by the tubing head. Alternately, the wellhead may not include a casing head. In this case, the tubing head is mounted directly to the casing string at the surface of the well. A reciprocating rod or tube or a rotating rod or tube is then run through the tubing string for production of the well. A typical wellhead may also further include a tubing rotator. Tubing rotators are used in the industry to suspend and rotate the tubing string within the wellbore. By rotating the tubing string, typical wear occurring within the internal surface of the tubing string by the reciprocating or rotating rod string is distributed over the entire internal surface. As a result, the tubing rotator may prolong the life of the tubing string. Further, the constant movement of the tubing string relative to the rod string may inhibit or reduce buildup of wax and other materials within the tubing string. Conventional tubing heads are not typically able to be retrofitted to accommodate the necessary structure of a tubing rotator, including the drive system for causing the rotation of the tubing string. Thus, the tubing head may require replacement in the event the operator of the well chooses to commence the use of a rotator subsequent to the initial completion of the well and the wellhead. Further, when a conventional tubing rotator is used in combination with a conventional tubing head, the rotator is typically mounted on top of the tubing head. This arrangement may increase the overall height of the wellhead and may result in the instability of the wellhead by weakening its overall structure. As well, in order to service the well, the tubing hanger and the connected tubing string must typically be removed from the well. However, any disturbance of the tubing string during servicing may lead to a blowout. To avoid this risk in a conventional well without a tubing rotator, the portion of the wellhead above the tubing head is typically removed and a blowout preventer is mounted to the tubing head. The tubing hanger with the attached tubing string are then removed through the blowout preventer. Where the wellhead includes a tubing rotator, the structure of the rotator tends to interfere with the installation of the blowout preventer. Thus, in order to service the well, the rotator, or at least a portion of it, must typically be removed from the tubing head. Removal of all or a portion of the rotator may require or result in disturbance of the tubing string, which may lead to a blowout. Further, when a rotator is in use in the wellhead, the tubing hanger is typically comprised of a swivel dognut assembly. The swivel dognut assembly is comprised of a rotatable mandrel, which is connected to and suspends the tubing string within the wellbore, and a drive system for rotating the mandrel which results in the rotation of the tubing string. The drive system is conventionally comprised of a system of gears which engages the mandrel either directly or indirectly to cause it to rotate. In order to remove these conventional rotators and tubing hangers for servicing of the well, the gear system must first be removed from the rotator such that the mandrel is no longer directly or indirectly engaged thereby. Where the gear system is not so removed, due to an error or oversight, the rotator and the wellhead may be seriously damaged resulting in the costly replacement of equipment, a loss of production during replacement of the equipment and a potential for the blowout of the well. As well, in order to service the well, a pup joint or servicing tool is typically threaded into the upper end of the inner rotatable mandrel of the swivel tubing hanger. However, upon the removal of the drive system for servicing of the well, the inner mandrel is typically able to freely rotate within the outer supporting structure of the tubing hanger. As a result, connection of the servicing tool may be problematic due to the difficulties encountered in obtaining and ensuring a secure connection between the servicing tool and the inner mandrel of the tubing hanger. This problem is typically addressed by the insertion of a key between the inner mandrel and the outer supporting structure of the tubing hanger during servicing of the well in order to inhibit the rotation of the inner mandrel. There is therefore a need in the industry for a tubing head capable of accommodating the functional structure or elements of a tubing rotator therein such that the tubing head may be retrofit and converted from its use as a conventional tubing head into its use as a combined tubing head and rotator. Further, there is a need for an apparatus which combines the functional elements of a tubing head and a tubing rotator in a single, integral unit. As well, there is a need for such a tubing head and apparatus that are relatively compact and that will facilitate the servicing of the well. More particularly, there is a need for such a tubing head and apparatus that permit the removal of the tubing string from the well therethrough without first requiring the removal of all or a portion of the tubing head or apparatus, including the drive system of the tubing rotator. Further, there is a need for such a tubing head and apparatus which permits the removal of the tubing string through a service blowout preventer mounted thereon without first moving the tubing string connected to the tubing rotator. Finally, there is a need for such an apparatus that facilitates the connection of a servicing tool to the components of the tubing rotator during the servicing of the well. DISCLOSURE OF INVENTION The present invention relates to a tubing head capable of accommodating the functional structure or elements of a tubing rotator therein such that the tubing head may be retrofit and converted from its use as a conventional tubing head into its use as a combined tubing head and rotator. Further, the present invention relates to an apparatus which combines the functional elements of a tubing head and a tubing rotator in a single, integral unit. As well, the present invention preferably relates to such a tubing head and apparatus that are relatively compact and that will facilitate the servicing of the well. In addition, the present invention relates to such a tubing head and apparatus which are configured such that the tubing string is removable from the well therethrough without first requiring the removal of all or a portion of the tubing head or apparatus, including the drive system of the tubing rotator. Further, the present invention preferably relates to such a tubing head and apparatus which are configured such that the tubing string is removable through a service blowout preventer mounted thereon without first moving the tubing string connected to the tubing rotator. Finally, the present invention preferably relates to such an apparatus which facilitates the connection of a servicing tool to the components of the tubing rotator of the apparatus during the servicing of the well. In a first aspect of the invention, the invention relates to a tubing head for accommodating a tubing rotator therein, the tubing head being of the type having an upper end, a lower end for attachment to a wellhead and an internal bore extending between the upper and lower ends, wherein the tubing rotator comprises a drive gear and a swivel tubing hanger for rotatably suspending a tubing string contained within a wellbore, the tubing hanger comprising an external surface for engaging the internal bore of the tubing head such that the tubing hanger may be suspended thereby and a driven gear for engaging the drive gear, the improvement which comprises: (a) the internal bore of the tubing head defining an internal surface for engaging the external surface of the tubing hanger such that the tubing hanger may be suspended by the tubing head; and PA1 (b) the tubing head defining a gear housing for containing the drive gear therein, wherein the gear housing communicates with the internal bore such that the drive gear may releasably engage the driven gear of the tubing hanger when the tubing hanger is suspended by the tubing head; PA1 (a) a tubing head having an upper end, a lower end for attachment to a wellhead and an internal bore extending between the upper and lower ends, wherein the internal bore of the tubing head defines an internal surface and wherein the tubing head further defines a gear housing which communicates with the internal bore; PA1 (b) a swivel tubing hanger for locating within the internal bore and for connecting to the tubing string, the tubing hanger comprising a driven gear and an external surface for engaging the internal surface of the tubing head such that the tubing hanger may be suspended by the tubing head; and PA1 (c) a drive gear for containing within the gear housing and for releasably engaging the driven gear of the tubing hanger; wherein the internal surface, the gear housing, the drive gear and the driven gear are configured such that when the drive gear is contained within the gear housing, the tubing hanger is located in the internal bore and the driven gear is engaging the drive gear, the tubing hanger is capable of being removed from the internal bore by pulling it through the upper end of the tubing head without first disengaging the drive gear from the driven gear. In a second aspect of the invention, the invention relates to an apparatus for attachment to a wellhead for suspending and rotating a tubing string contained within a wellbore, the apparatus comprising: wherein the internal surface, the gear housing, the drive gear and the driven gear are configured such that when the drive gear is contained within the gear housing, the tubing hanger is located in the internal bore and the driven gear is engaging the drive gear, the tubing hanger is capable of being removed from the internal bore by pulling it through the upper end of the tubing head without first disengaging the drive gear from the driven gear. In the first and second aspects, any configuration of the tubing head able to achieve the functions or purpose of the tubing head as described above may be used However, preferably, the internal bore of the tubing head defines a minimum diameter of the bore. Further, the gear housing is preferably configured such that when the drive gear is contained within the gear housing, it does not protrude into the internal bore within the minimum diameter. As well, the internal surface of the tubing head preferably defines a maximum diameter of the internal bore which is about equal to a maximum diameter of the tubing hanger. When a service blowout preventer is mounted on the upper end of the tubing head and the tubing hanger is located in the internal bore, the maximum diameter of the tubing hanger preferably permits the tubing hanger to be removed from the internal bore by pulling it through the blowout preventer in order to service the well. Further, in the preferred embodiment, the drive gear and the driven gear engage each other between the minimum diameter and the maximum diameter of the internal bore. The drive gear and the driven gear may be comprised of any compatible gears suitable for performing their functions or purpose and which engage each other between the minimum and maximum diameters of the internal bore. However, preferably, the drive gear is comprised of a worm and the driven gear is comprised of a worm gear. Further, in the preferred embodiment, the worm and the worm gear are non-enveloping in order to facilitate the removal of the tubing hanger from the internal bore without first disengaging the worm from the worm gear. The worm gear is comprised of a plurality of worm gear teeth and the worm is comprised of a plurality of worm teeth. These worm gear and worm teeth may have any shape or configuration permitting the removal of the tubing hanger from the internal bore without first disengaging the worm from the worm gear. In addition, the shape and configuration preferably facilitate the feeding of the worm gear onto the worm and the feeding of the tubing hanger into the internal bore of the tubing head. In the preferred embodiment, a lower end of each worm gear tooth is tapered inwardly towards a centre of the tooth in order to facilitate the feeding of the worm gear onto the worm. In addition, the lower end of each worm gear tooth is sloped downwardly from a top face to a bottom face of the tooth in order to facilitate the feeding of the tubing hanger into the internal bore of the tubing head. Finally, a crest of each worm tooth is tapered to facilitate the feeding of the worm gear onto the worm. The tubing head is preferably further comprised of any means, structure, mechanism or device for inhibiting the longitudinal movement of the tubing hanger in a direction toward the upper end of the tubing head. Preferably, the upwards longitudinal movement of the tubing hanger is inhibited by the tubing head which is comprised at least one adjustable holddown screw for engagement with the tubing hanger such that when the holddown screw is adjusted for engagement with the tubing hanger, longitudinal movement of the tubing hanger in a direction toward the upper end of the tubing head is inhibited. In the preferred embodiment, the tubing head is comprised of at least two holddown screws located adjacent the upper end of the tubing head. In addition, the tubing head is further preferably comprised of means for mounting the tubing head on the wellhead. Any means, mechanism, structure or device capable of and suitable for temporarily or permanently mounting or connecting the tubing head to the wellhead may be used. Preferably, the mounting means are capable of connecting the lower end of the tubing head on the wellhead. In addition, the mounting means may be suitable for mounting or connecting the lower end of the tubing head to any portion or component of the wellhead, but preferably, the mounting means are compatible with mounting the tubing head to a casing string or a casing head or an existing tubing head. For instance, when the wellhead is comprised of a casing string, the mounting means may be comprised of a mounting portion of the internal bore of the tubing head adjacent the lower end, which mounting portion is adapted for connection to the casing string. When the wellhead is comprised of a casing head or an existing tubing head, the mounting means may be comprised of a lower surface on the lower end of the tubing head, which lower surface is adapted for connection to the casing head or the existing tubing head. Preferably, in this case, the lower surface of the tubing head is comprised of a mounting flange. Finally, the tubing head is further preferably comprised of means for connecting the upper end of the tubing head to other wellhead equipment. Any means, mechanism, structure or device capable of and suitable for temporarily or permanently mounting or connecting the upper end of the tubing head to the other wellhead equipment may be used. The tubing hanger may be comprised of any swivel tubing hanger compatible with its use within the tubing head and which permits the functioning of the apparatus as described herein. However, preferably, the tubing hanger is further comprised of: a supporting member comprising the external surface of the tubing hanger; and a supported member rotatably supported within the supporting member such that the longitudinal movement of the supported member relative to the supporting member in a direction toward the lower end of the tubing head is inhibited, the supported member having an upper end and a lower end for connecting to the tubing string and wherein the supported member is associated with the driven gear such that rotation of the driven gear causes the supported member to rotate within the supporting member. The supported member may be associated with the driven gear in any manner or by any means, mechanism, structure or device which permits the functioning of the tubing hanger as described herein and which permits the drive gear to engage the driven gear. However, in the preferred embodiment, the driven gear is fixedly mounted about the supported member such that the driven gear extends from the supported member towards the gear housing of the tubing head for engagement with the drive gear. The tubing hanger further preferably comprises means for inhibiting the longitudinal movement of the supported member relative to the supporting member in a direction toward the upper end of the tubing head. Any means, structure, mechanism or device for inhibiting the upwards longitudinal movement of the supported member relative to the supporting member may be used. However, preferably, the inhibiting means is comprised of the abutment of the driven gear and the supporting member. Any means, mechanism, device or structure capable of supporting the supported member in the required manner which is compatible with the function of a the tubing hanger, may be used. However, preferably, the supported member is rotatably supported within the supporting member by at least one bearing located between the supported member and the supporting member such that the bearing is seated on the supporting member and the supported member is rotatably supported upon the bearing. Any bearing suitable for, and compatible with, this intended purpose or function may be used. For instance, the bearing may be comprised of a thrust bearing, a radial bearing, a tapered roller bearing or a combination thereof. In the preferred embodiment, the bearing is comprised of a thrust bearing in combination with a bushing sleeve.
043022855	claims	1. A neutron activation analysis installation comprising: a neutron generator, a target chamber of said neutron generator; a receiving and loading assembly; a transport means communicating said receiving and loading assembly with said target chamber; a test sample impurity concentration measuring unit; a through channel communicating said impurity concentration measuring unit with said receiving and loading assembly; a through lateral port in said channel; an irradiated sample surface layer removal unit located against said port on one side of said channel; an irradiated sample distribution assembly disposed against said port on the opposite side of said channel with respect to said surface layer removal unit; an air cylinder being the main part of said irradiated sample distribution assembly; a hollow rod in said air cylinder; a bar arranged along the axis of said hollow rod; a sample receiver rigidly fixed on the end of said bar; said bar disposed in a manner allowing its rotation about the longitudinal axis thereof and reciprocating motion through said port in said channel so that in one extreme position said bar does not reach said channel leaving it vacant, in the intermediate position of said bar said sample receiver is found in said channel blocking the latter and in the other extreme position of said bar said sample receiver passes through said port in said channel and gets into said surface layer removal unit. 2. An installation as claimed in claim 1, wherein a mechanism turning said bar about the axis thereof comprises: a piston contained within said hollow rod encompassing said bar and secured thereon in a manner allowing sliding motion along the latter; a screw slot in said rod; a carrier rigidly connected with said piston and installed in a manner allowing its motion through said slot. 3. An installation as claimed in claim 1, wherein said surface layer removal unit includes at least three communicating chambers arranged successively in the direction of reciprocating motion of said bar; the position of the last chamber in the direction of progressive motion of said bar corresponding to said extreme position of said bar: the member of the air locks arranged on the air cylinder being less by one than the number of said chambers. 4. An installation as claimed in claim 2, wherein said irradiated sample surface layer removal unit includes at least three communicating chambers arranged successively in the direction of reciprocating motion of said bar; the position of the last chamber in the direction of progressive motion of said bar corresponding to said extreme position of said bar; the number of the air locks arranged on the air cylinder being less by one than the number of said chambers.
054147425	claims	1. A leak-detection system for detecting a leaking container having a surface thereon and a material leaking therefrom, the material capable of adhering to the surface of the container as the material leaks from the container, comprising: (a) enclosure means surrounding the container for enclosing the container; (b) detector means associated with said enclosure means for detecting the leaking material; and (c) fluid injection means associated with said enclosure means for injecting a fluid into said enclosure means to remove the material adhering to the surface and to carry the material removed thereby to said detector means, so that said detector means detects the material leaking from the container. (a) enclosure means surrounding the container for enclosing the container; (b) detector means connected to said enclosure means for detecting the leaking material; (c) fluid injection means connected to said enclosure means for injecting a fluid into said enclosure means to remove the material adhering to the exterior surface and to carry the material removed thereby to said detector means so that said detector means detects the material leaking from the container; and (d) pressure relief means connected to the container for elevating the container for relieving the internal pressure in the container, so that the material is prevented from hiding-out in the container as the internal pressure is relieved. (a) an enclosure defining a cavity therein surrounding the container for enclosing the container, the cavity containing a fluid medium covering the exterior surface and defining an external pressure acting against the exterior surface; (b) a radiation detector in communication with the cavity defined by said enclosure for detecting the radioactive material leaking through the breach; (c) a gas injector in communication with the cavity defined by said enclosure for injecting a gas into the cavity to remove the radioactive material adhering to the exterior surface and to carry the radioactive material removed thereby to said radiation detector, so that said radiation detector detects the radioactive material leaking from the container in order to detect the leaking container; (d) an elevator connected to the container for elevating the container in the cavity, so that the external pressure acting against the exterior surface is reduced to relieve the internal pressure in the container and so that the radioactive material leaks through the breach as the internal pressure is relieved to prevent the radioactive material from hiding-out in the container. (a) a suction pump in communication with the cavity defined by said enclosure for suctioning the radio-active material therefrom; (b) a radiation-sensitive sensor in communication with the suction pump for sensing the radiation of the radioactive material suctioned by the suction pump, said sensor adapted to generate a sensor output signal in response to the radiation sensed thereby; (c) an analyzer connected to said sensor for receiving the sensor output signal and for providing an analysis of the sensor output signal, said analyzer adapted to generate an analyzer output signal associated with the analysis provided thereby; and (d) a controller connected to said analyzer for controlling said analyzer. (a) a stationary enclosure defining a cavity surrounding the fuel rod for enclosing the fuel rod therein, the cavity containing a liquid medium covering the exterior surface of the fuel rod and defining a liquid-free volume in the cavity, the liquid medium defining a hydrostatic pressure acting against the exterior surface of the fuel rod; (b) a radiation detector in communication with the liquid-free volume for detecting the radioactive fission product material leaking through the breach, said radiation detector including: (d) a movable elevator connected to said fuel rod for elevating the fuel rod in the cavity defined by said enclosure, so that the hydrostatic pressure acting against the exterior surface of the fuel rod is reduced to relieve the internal pressure in the fuel rod and so that the radioactive fission product material expands and thereafter leaks through the breach as the internal pressure is relieved to prevent the radioactive fission product material from hiding-out in the fuel rod. (a) enclosing the container by surrounding the container with an enclosure; (b) detecting the material leaking from the container by operating a detector associated with the enclosure; and (c) injecting a fluid into the enclosure for removing the material adhering to the exterior surface and for carrying the material to the detector, so that the detector detects the material leaking from the container. (a) enclosing the fuel rod by surrounding the fuel rod with an enclosure defining a cavity in the enclosure, the cavity containing a liquid medium therein covering the exterior surface of the fuel rod and defining an external pressure acting against the exterior surface of the fuel rod, the cavity defining a liquid-free volume in the cavity; (b) injecting a gas into the liquid medium by operating a gas injector in communication with the liquid medium so that a multiplicity of upwardly rising gas bubbles are generated in the liquid medium for removing the radioactive fission product material adhering to the exterior surface of the fuel rod and for carrying the radioactive fission product material removed thereby to the liquid-free volume; (c) detecting the radioactive fission product material leaking through the breach by operating a radiation detector in communication with the liquid-free volume; and (d) elevating the fuel rod in the cavity defined by the enclosure by operating an elevator connected to the fuel rod so that the external pressure acting against the exterior surface is reduced to relieve the internal pressure in the fuel rod and so that the radioactive fission product material expands and thereafter leaks through the breach as the internal pressure is relieved to prevent the radioactive fission product material from hiding-out in the fuel rod. (a) suctioning the radioactive fission product material from the liquid-free volume by operating a suction pump in communication with the liquid-free volume; (b) sensing the radiation of the radioactive fission product material suctioned by the suction pump by operating a radiation-sensitive sensor in communication with the suction pump, the sensor capable of generating a sensor output signal in response to the radiation sensed by the sensor; (c) providing an analysis of the sensor output signal by operating an analyzer connected to the sensor, the analyzer capable of receiving the sensor output signal and thereafter capable of generating an analyzer output signal associated with the analysis provided by the analyzer; and (d) controlling the analyzer by operating a controller connected to the analyzer. (a) withdrawing the fission product material from the liquid-free volume defined by the cavity by operating a recirculating assembly in communication with the liquid-free volume; and (b) returning the collected gas to the cavity by operating the recirculation assembly. 2. The leak-detection system of claim 1, further comprising recirculating means connected to said enclosure means and to said fluid injection means for recirculating the fluid through said enclosure means. 3. A leak-detection system for detecting a leaking container having an exterior surface thereon and a material leaking therefrom, the container having a predetermined internal pressure, the material capable of adhering to the exterior surface of the container as the material leaks from the container, comprising: 4. The leak-detection system of claim 3, further comprising recirculation means connected to said enclosure means and to said fluid injection means for recirculating the fluid through said enclosure means. 5. A leak-detection system for detecting a leaking container having a radioactive material leaking through a breach in an exterior surface of the container, the container having a predetermined internal pressure, the radioactive material capable of adhering to the exterior surface as the radioactive material leaks through the breach, comprising: 6. The leak-detection system of claim 5, wherein said radiation detector comprises: 7. The leak-detection system of claim 6, wherein said radiation detector further comprises a display connected to said analyzer for receiving the analyzer output signal and for displaying the analyzer output signal received thereby. 8. The leak-detection system of claim 5, further comprising a recirculation assembly in communication with the cavity defined by said enclosure and connected to said gas injector for recirculating the gas through said enclosure after being analyzed by said analyzer. 9. The leak-detection system of claim 5, further comprising a support frame connected to said elevator and to said enclosure for supporting said elevator and said enclosure. 10. A leak-detection system for detecting a leaking nuclear fuel rod having a radioactive fission product material leaking through a breach in an exterior surface of the fuel rod, the fuel rod having a predetermined internal pressure, the radioactive fission product material capable of adhering to the exterior surface of the fuel rod as the radioactive fission product material leaks through the breach, the leak-detection system comprising: 11. The leak-detection system of claim 10, further comprising a recirculation assembly in communication with the liquid-free volume defined by said enclosure and connected to said gas injection manifold for recirculating the fission product material through said enclosure. 12. The leak-detection system of claim 10, further comprising a support frame connected to said elevator and to said enclosure for supporting said elevator and said enclosure. 13. A leak-detection method for detecting a leaking container having a material leaking from an exterior surface thereof, the material capable of adhering to the exterior surface of the container, comprising the steps of: 14. The leak-detection method of claim 13, further comprising the step of recirculating the fluid through the enclosure. 15. A leak-detection method for detecting a leaking nuclear fuel rod having a radioactive fission product material leaking through a breach in an exterior surface of the fuel rod, the fuel rod having a predetermined internal pressure, the radioactive fission product material capable of adhering to the exterior surface as the radioactive fission product material leaks through the breach, the leak-detection method comprising the steps of: 16. The leak-detection method of claim 15, wherein said step of detecting the radioactive fission product material comprises the steps of: 17. The leak-detection method of claim 16, wherein said step of detecting the radioactive fission product material further comprises the step of displaying the analyzer output signal by operating display connected to the analyzer. 18. The leak-detection method of claim 15, further comprising the step of recirculating the gas through the enclosure. 19. The leak-detection method of claim 18, wherein said step of recirculating the gas through the enclosure comprises the steps of: 20. The leak-detection method of claim 15, further comprising the step of supporting the elevator and the enclosure by providing a support frame connected to the elevator and the enclosure.
	summary
	claims	1. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that a density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture substantially reduce at the same demagnification both in X and Y directions when the optical axis extends in Z directions and form an image on the substrate without forming any crossover between said character aperture and the substrate; and a second deflector which deflects the charged particle beams passing through said character aperture by means of an electrostatic field to scan the substrate with the charged particle beams. 2. A charged particle beam exposure system according to claim 1 , wherein said reducing projecting optical system includes multi-pole lenses the number of which is N 1 , N 1 being a natural number of 3 or more. claim 1 3. A charged particle beam exposure according to claim 2 , wherein said second deflector deflects the charged particle beams in the X directions and the charged particle beams in said Y directions independently of each other. claim 2 4. A charged particle beam exposure system according to claim 3 , wherein said N 1 is 4. claim 3 5. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that a density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture substantially reduce at the same demagnification both in X and Y directions when the optical axis extends in Z directions and form an image on the substrate without forming any crossover between said character aperture and the substrate, wherein said reducing projecting optical system includes four multi-pole lenses; and a second deflector which deflects the charged particle beams passing through said character aperture by means of an electrostatic field to scan the substrate with the charged particle beams, wherein said second deflector deflects the charged particle beams in the X directions and the charged particle beams in said Y directions independently of each other, and said four multi-pole lenses are controlled to form first through fourth electrostatic fields so that said first through fourth electrostatic fields sequentially form a divergent electrostatic field, a divergent electrostatic field, a convergent electrostatic field and a divergent electrostatic field in one direction of the X and Y directions and so as to sequentially form a convergent electrostatic field, a convergent electrostatic field, a divergent electrostatic field and a convergent electrostatic field in the other direction of the X and Y directions. 6. A charged particle beam exposure system according to claim 5 , wherein said second deflector includes a plurality of electrostatic deflectors. claim 5 7. A charged particle beam exposure system according to claim 6 , wherein said second deflector superimposes an electrostatic deflection field on said multi-pole lens field to deflect the charged particle beams. claim 6 8. A charged particle beam exposure system according to claim 7 , which further comprises a first main deflector which includes multi-pole electrodes, said first main deflector being provided between a second multi-pole lens and a third multi-pole lens of said first multi-pole lenses, claim 7 wherein said multi-pole lens is controlled to form first through fourth electrostatic fields so that said first through fourth electrostatic fields sequentially form a divergent electrostatic field, a divergent electrostatic field, a convergent electrostatic field and a divergent electrostatic field in the X directions and to sequentially form a convergent electrostatic field, a convergent electrostatic field, a divergent electrostatic field and a convergent electrostatic field in the Y directions, said third multi-pole lens and said fourth multi-pole lens serve as a second main deflector for superimposing an electrostatic deflection field on said multi-pole lens field, and said second deflector includes said first main deflector and said second main deflector, said second deflector deflecting the charged particle beams independently in said X and Y directions by deflecting the charged particle beams in the X directions by a first main deflection field formed by said first main deflector and a second main deflection field formed by said second main deflector and deflecting the charged particle beams in the Y directions by said second main deflection field. 9. A charged particle beam exposure system according to claim 8 , wherein said second deflector further includes a sub deflector downstream of said N 1 -th multi-pole lens. claim 8 10. A charged particle beam exposure system according to claim 9 , wherein said multi-pole lens is an electrostatic lens. claim 9 11. A charged particle beam exposure system according to claim 10 , wherein said electrostatic lens is a quadrupole lens. claim 10 12. A charged particle beam exposure system according to claim 11 , wherein said multi-pole lens has M (M=4N 2 , N 2 is a natural number of 2 or more) electrodes, adjacent N 2 electrodes thereof serving as a set of quadrupole lenses. claim 11 13. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture substantially reduce at the same demagnification both in X and Y directions when the optical axis extends in Z directions and form an image on the substrate without forming any crossover between said character aperture and the substrate, wherein said reducing projecting optical system includes four multi-pole lenses, and the inside diameter of said first multi-pole lens and said second multi-pole lens is a first inside diameter and the inside diameter of said third multi-pole lens and said fourth multi-pole lens is a second inside diameter which is greater than said first inside diameter; and a second deflector which deflects the charged particle beams passing through said character aperture by means of an electrostatic field to scan the substrate with the charged particle beams, wherein said second deflector deflects the charged particle beams in the X directions and the charged particle beams in said Y directions independently of each other. 14. A charged particle beam exposure system according to claim 13 , which further comprises a first shielding electrode which is provided in the vicinity of the top and bottom faces of said multi-pole lens in the Z directions. claim 13 15. A charged particle beam exposure system according to claim 14 , wherein the inside diameter of said first shielding electrode provided between the first multi-pole lens and the second multi-pole lens, of said first shielding electrodes, is a fourth inside diameter smaller than a third inside diameter which is the inside diameter of other first shielding electrode. claim 14 16. A charged particle beam exposure system according to claim 15 , wherein said first shielding electrode with said fourth inside diameter serves as a first alignment aperture for the charged particle beams or a first detector for the charged particle beams. claim 15 17. A charged particle beam exposure system according to claim 16 , which further comprises second shielding electrodes which are provided in the vicinity of the top and bottom faces of said first and second deflectors, respectively. claim 16 18. A charged particle beam exposure system according to claim 17 , wherein the inside diameter of said second shielding electrode provided in the vicinity of the top face of said first main deflector, of said second shielding electrodes, is a fifth inside diameter which is smaller than said third inside diameter. claim 17 19. A charged particle beam exposure system according to claim 18 , wherein said second shielding electrode with said fifth inside diameter serves as a second alignment aperture for the charged particle beams or a second detector for the charged particle beams. claim 18 20. A charged particle beam exposure system according to claim 19 , wherein each of the lens lengths of said multi-pole lenses is about 6 mm, said first inside diameter being about 5 mm, said second inside diameter being about 10 mm, and the optical length between said character aperture and the substrate being 110 mm or less. claim 19 21. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture form an image on the substrate without forming any crossover between said character aperture and the substrate; and a second deflector which deflects the charged particle beams passing through said character aperture by means of an electrostatic field to scan the substrate with the charged particle beams. 22. A charged particle beam exposure system according to claim 21 , wherein said reducing projecting optical system includes four multi-pole lenses which are controlled to form first through fourth electrostatic fields so that said first through fourth electrostatic fields sequentially form a divergent electrostatic field, a divergent electrostatic field, a convergent electrostatic field, and a divergent electrostatic field in one direction of X and Y directions and so as to sequentially form a convergent electrostatic field, a convergent electrostatic field, a divergent electrostatic field, and a convergent electrostatic field in the other direction of the X and Y directions. claim 21 23. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture form an image on the substrate without forming any crossover between said character aperture and the substrate; and a second deflector which deflects the charged particle beams passing through said character aperture by means of an electrostatic field in X directions and the charged particle beams in Y directions independently of each other to scan the substrate with the charged particle beams. 24. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which forms a multi-pole lens field so that the charged particle beams passing through said character aperture substantially reduce at the same demagnification both in X and Y directions when the optical axis extends in Z directions and form an image on the substrate without forming any crossover between said character aperture and the substrate; and a second deflector which includes an electrostatic deflector and deflects the charged particle beams passing through said character aperture by superimposing the electrostatic field on said multi-pole lens field to scan the substrate with the charged particle beams. 25. A charged particle beam exposure system comprising: a charged particle beam emitting device which generates charged particle beams with which a substrate is irradiated, said charged particle beam emitting device generating the charged particle beams at an accelerating voltage which is lower than that at which an influence of a proximity effect occurs, the proximity effect being a phenomenon in which at least one of a secondary charged particle and a reflected charged particle which is produced from the surface of the substrate irradiated with the charged particle beams influences an exposure extent of a pattern which is adjacent to a pattern to be written; an illumination optical system which adjusts a beam diameter of the charged particle beams so that density of the charged particle beams is uniform; a character aperture in which an aperture hole is formed in a shape corresponding to a desired pattern to be written; a first deflector which deflects the charged particle beams by an electrostatic field so that the charged particle beams have a desired sectional shape and travel towards a desired aperture hole and which returns the charged particle beams passing through said aperture hole to an optical axis thereof; a reducing projecting optical system which includes four multi-pole lenses which form a multi-pole lens field, respectively, so that the charged particle beams passing through said character aperture form an image on the substrate without forming any crossover between said character aperture and the substrate, said multi-pole lenses being controlled to form first through fourth electrostatic fields to sequentially form a divergent electrostatic field, a divergent electrostatic field, a convergent electrostatic field, and a divergent electrostatic field in X directions and to sequentially form a convergent electrostatic field, a convergent electrostatic field, a divergent electrostatic field, and a convergent electrostatic field in Y directions; and a second deflector which includes a first main deflector and a second main deflector and which deflects the charged particle beams passing through said character aperture independently in said X and Y directions to scan the substrate with the charged particle beams by deflecting the charged particle beams in the X directions by a first main deflection field formed by said first main deflector and a second main deflection field formed by said second main deflector and deflecting the charged particle beams in the Y directions by said second main deflection field, said first main deflector being provided between said second multi-pole lens and said third multi-pole lens, and said third multi-pole lens and said fourth multi-pole lens serving as said second main deflector to superimpose an electrostatic deflection field on said multi-pole lens field.
041347897	abstract	Refuelling of a nuclear reactor and especially a PWR is carried out in the steps which consist in removing and storing the reactor closure head, in moving the control rods from a bottom position to the top position and securing the rods to the upper internal structure, in removing and storing the assembly constituted by the upper internal structure and the control rods, in replacing the spent fuel and in re-positioning the upper internal structure and the closure head.
	abstract	A scanning apparatus which performs scan on an object with a charged particle beam includes: a blanking deflector configured to individually blank a plurality of charged particle beams based on control data; a scanning deflector configured to collectively deflect the plurality of charged particle beams to perform the scan; and a controller. The controller is configured to hold first data used to obtain error in a scanning amount and a scanning direction of the scanning deflector relative to a reference scanning amount and a reference scanning direction with respect to each of the plurality of charged particle beams, and to generate the control data based on the first data so that the scan is performed for a target region on the object.
	summary
042808723	abstract	In a fast reactor having a diagrid structure supported on the bottom wall of a reactor vessel containing the core and liquid metal coolant, a core catcher serves in the event of core melt-down to prevent hot debris carried down by the liquid metal from coming into contact with the vessel walls. The core catcher comprises a single collecting tray having a large area, a central chimney and a bearing shell extending parallel to the bottom wall of the reactor vessel. An enclosed space is formed between the bottom wall, the diagrid support structure and the diagrid and contains the collecting tray. Under melt-down conditions, the temperature differences produced by the molten fuel deposited on the tray and the presence of the central chimney have the effect of setting up a natural circulation of liquid metal and consequently of cooling the fuel.
	summary
048184705	summary	This invention relates to the ultrasound testing of steam separator hold down bolts in a boiling water nuclear reactor (BWR). STATEMENT OF THE PROBLEM BWRs are periodically refueled. As part of this refueling procedure, the reactor dome is removed, the steam dryer assembly lifted out of the reactor vessel and the cylindrical steam separator is then lifted out of the reactor vessel. The dome, dryer and separator are placed in a holding pool so that water shields any radio activity from working personnel. This invention relates to a problem that is unique to the steam separator and provides for inspection of the shroud hold down bolts when the steam separator is in the holding pool. When the reactor is assembled and operating, the steam separator must be held in position to a shroud overlying the reactor core. This holding of the steam separator in position is accomplished by the shroud hold down bolts. The shroud hold down bolts are relatively complex bolt members. These bolt members are elongate, extending from the top of the steam separator assembly to the bottom of the steam separator assembly a distance of about 13 to 17 feet. The bolts are manipulated and operated from the top, and fasten the steam separator to the shroud overlying the reactor core at the bottom. Because these bolts are well known in the prior art, they will be set forth herein only in sufficient detail so that the problems that they generate with respect to periodic inspections can be understood. The shroud hold down bolts are typically spaced at equal radial intervals around the cylindrical steam separator. Each bolt includes a central tension member and an outer compression sleeve member with both members extending substantially the entire length of the bolts. Because of the relative proximity of the bottom of the bolts to the top of the radioactive reactor core, the bottom of the bolts are highly radioactive. The lower portion of the inner tension member has a lug which is rectangular in plan on the bottom for engagement with a bracket on the shroud at the top of the core. This rectangular lug rotates from a radial alignment where release of the bolt from a mating shroud bracket can occur to a position normal to a radial alignment where attachment of the bolt at the rectangular lug to the shroud bracket can occur. When the rectangular lug is engaged with the bracket, the outer compression member bears down on the lower portion of the steam separator, places the inner member under tension from the shroud bracket and holds the steam separator to the rest of the reactor during operation. All manipulations relating to the tightening or the loosening of the bolts occurs from the very top of the bolts. This enables engagement and disengagement of the bolts to be remotely manipulated, typically in a submerged disposition, so that radio activity is not a threat to operating personnel. Tightening of the engaged bolts can be easily understood. The bolts are tightened and loosened from the top of the steam dryer assembly. Assuming that the lug is engaged with the bracket, the outer compression sleeve of the bolt is forced downwardly over the inner tension member. The outer compression member bears downwardly on the lower portion of the steam separator. At the same time, the inner tension member pulls upwardly into the bracket on the shroud at the top of the reactor core. The result is that the steam separator is held to the top of the shroud overlying the core. Loosening of the bolts is more complex. Adjacent the bottom of the bolts, attached to the outer compression member below the attachment at the bottom of the steam separator is a sleeve. This sleeve has a window. The purpose of the window is to maintain the lugs of the bolts in the open position when the bolts are fully loosened. The lower end of the inner tension member is transpierced with a shaft normal to the sleeve. This shaft extends through the window in the sleeve. The purpose of the shaft is to co-act with a notch in the window of the sleeve to maintain the shroud bolt with its lug in the open position once it is fully loosened. When the shroud bolt is fully loosened, the rectangular lug at the bottom of the tension member falls below the shroud bracket. When the rectangular lug falls below the shroud bracket, it is free to rotate. Rotation of the rectangular lug and the attached tension member occurs to a position where the lug is radially aligned with respect to the shroud bracket. With such radial alignment, release from the shroud bracket can occur. Likewise, when the tension member and its rectangular lug rotate, the shaft in the window likewise rotates. This rotation of the shaft in the window continues until the rectangular lug is radially aligned and the transpiercing and protruding shaft engages the notch in the window of the sleeve. Once engagement to the notch in the window of the sleeve occurs, the rectangular lug at the bottom of the tension member is maintained in a position of radial alignment where release from the shroud bracket can occur. Assuming that all shroud bolts are fully loosened and their respective lugs retained in the radially aligned position, lifting the steam separator from the shroud overlying the core can occur. Movement of the steam separator to the holding pool takes place. Unfortunately, such shroud hold down bolts crack. The bolts crack on the inner tension member adjacent the lug, usually under the sleeve. They are subject to a metallurgical cracking phenomena known as inter granular stress crack corrosion. Simply stated, the oxygen in the water of the reactor combined with both the material and the tension on the bolts can cause cracking to occur. This cracking is intermittent and highly unpredictable. Further, the cracking defect is latent in at least two respects. First, inter granular stress crack corrosion (IGSCC) is hard to locate by observation--for example an under water TV camera. Second, the most susceptible location for the IGSCC has been found to be a location underneath the locking sleeve at the bottom of the bolt. Conventional inspection techniques are not desirable. Any inspection technique that involves removal and manipulation of the highly radioactive bolts is prohibitively expensive. Further, since the presence of the cracking is highly intermittent, routine inspection capability is desired for checking against this shroud bolt defect. The reader will understand that the complete understanding of the latent defect is relatively complex. Consequently, insofar as understanding of the problem to be solved constitutes invention, invention is claimed. SUMMARY OF THE PRIOR ART Ultra sonic testing is known. Typically, piezoelectric transducers are directly placed by hand upon a member to be tested. A sonic signal is imparted to the member. The transducer listens for a returned and reflected signal. Once the signal is returned analysis of the tested member can be made. Such ultra sound waves when transducing a rod such as the inner tension member have three types of waves traveling through the rod. These waves include longitudinal waves, refracted waves, and shear waves. It is by the analysis of these wave forms, that defects can be located. Since the analysis of such wave forms is well known in the prior art, further discussion will not be added here. SUMMARY OF THE INVENTION An apparatus for the remote examination of peripheral shroud hold down bolts on steam separators used in boiling water reactors (BWRs) is disclosed. The shroud hold down bolts surround the generally cylindrical steam separator at the outside circumference and are generally coextensive in length with the steam separator length, being in the order of 150 to 205 inches in length. During reactor outages, all bolts--between 24 and 48 in number--have rectangular holding lugs at the bottom of the hold down bolts radially aligned with respect to the steam separator to clear mating brackets on a shroud overlying the reactor core. When all bolts have their lugs radially aligned for release the steam separator with its attached bolts is moved to a holding pool and remains immersed in water to protect maintenance personnel from ambient radioactivity. The testing apparatus normally is used while the steam separator is in the holding pool with its respective lugs radially aligned. The testing apparatus includes a depending pole having attached at the bottom thereof an aluminum shoe. The shoe has a flat, upwardly exposed bottom and opens to one side at gathering surfaces to receive the lower ends of the shroud bolts. The upwardly exposed bottom of the shoe defines an aperture through which an upwardly exposed piezoelectric device is exposed for direct contact with the bottom of the bolt. An overlying clamp member is provided to clamp the lug onto the bottom of the shoe for test. The clamp member defines a receiving slot to receive the shaft of the bolt immediately overlying the rectangular lug. This clamp member is positioned at the slot on the shaft overlying the rectangular lug and thereafter moved down to and towards the lug by a pneumatic cylinder. The clamp member slides over the shaft at the slot into contact with the top of the lug. The clamp member clamps the lug end of the bolt securely onto the upwardly exposed piezoelectric device on the upwardly exposed bottom of the shoe. A piezoelectric ultrasonic test is then run from the bottom and radioactive portion of the bolt to and towards the top of the bolt. Testing for longitudinal sound waves, refracted sound waves and shear sound waves for inter granular stress corrosion cracking can occur despite the radioactive and remote under water location of the bolts. OTHER OBJECTS AND ADVANTAGES An object of this invention is to set forth a test protocol for a reactor steam separator shroud bolt without necessitating removal of the bolt. An advantage of the disclosed protocol is that regular testing of the bolts can occur concurrently with reactor outages concurrent to refueling. Further, no removal or disassembly of the steam separator is required for the disclosed test. Further, it has been found that the outer compression member, sleeved about the inner tension member, does not interfere with the desired testing. In short, a highly advantageous and economical ultrasonic test is disclosed.
	summary
	abstract	The process of the present application differs substantially from the prior art, as it facilitates the deliberate extraction of electrons from atoms and molecules during the production of positive ions, as compared with occasionally and accidentally knocking them away. It is an energy efficient process for the extraction and capture of electrons, production of positive ions and negative ions, the construction of molecules and the selective decomposition of molecules. These results are accomplished by the forcible extraction of electrons from the object molecules and atoms. The present process is superior to any other intended for the production of positive ions and the composition and the decomposition of molecules, because it not only simplifies the process, but it also speeds the process, allowing a continuous stream or beam of particles to be so converted to positive ions. Additionally, the present process demonstrates its superiority to any other because it is extremely efficient, in that, once the system is fully charged, it requires only a small maintenance energy to sustain operation. Furthermore, by the reversal of electric polarity, the process allows the production of a continuous stream or beam of negative ions.
055725635	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a mirror unit (reflecting-mirror unit), for utilizing X-rays or the like having a short wavelength, in an exposure apparatus, which is used for manufacturing semiconductor integrated circuits or the like, and an exposure apparatus including the mirror unit. 2. Description of the Related Art Among X-ray exposure apparatuses for exposing a resist, coated on a wafer and provided in the proximity of a pattern on a mask, with X-rays emanating from an illuminating light source, apparatuses which utilize synchrotron orbit radiation (SOR) light as an X-ray light source have been proposed. The synchrotron radiation light is obtained from an SOR apparatus which emits light on an orbital plane of electrons. While the light from the SOR apparatus has a large beam path in a direction parallel to the orbital plane of the electrons, the light has a very small spread, such that the divergence angle of the light is approximately a few mrad (milliradians), in a direction perpendicular to the orbital plane of the electrons. Accordingly, in order to obtain an exposure region of a few centimeters, which is required for an exposure apparatus, the synchrotron radiation light must be spread in the direction perpendicular to the orbital plane of the electrons. Various methods have been proposed for that purpose. In one method, a plane mirror swings around an axis perpendicular to the direction of the radiation light and parallel to the orbital plane of the electrons. In another method, reflected light is spread in a direction perpendicular to the orbital plane of the electrons by a convex mirror. A conventional mirror supporting device in a method of obtaining an exposure region using a convex mirror is disclosed in Japanese Patent Laid-open Application (Kokai) No. 5-100096 (1993) filed by the assignee of the present application. FIG. 13 is a partially-cutaway schematic perspective view of a conventional exposure apparatus. FIG. 14 is an enlarged cross-sectional view of a mirror unit shown in FIG. 13. As shown in FIGS. 13 and 14, a supporting plate 103, on which a mirror 101 is mounted via a mirror holder 102, is provided within a vacuum chamber 100, so that the entire mirror 101 is provided within the vacuum chamber 100. The supporting plate 103 has a threaded hole 104, and is supported on a mirror supporter 107, which is present outside the vacuum chamber 100, via an internal flange 111, and a supporting rod 106 including an exhaust port 109. The internal flange 111 is connected to the vacuum chamber 100 via a bellows 105, and the mirror supporter 102 is supported on the supporting plate 103 using bolts (not shown). The mirror supporter 107 is positioned by being driven by a driving motor 117, and the tilt of the mirror supporter 107 is adjusted by a tilting plate 116 provided on a reference frame 115. Reference numeral 118 represents a guide for guiding the mirror supporter 107, and reference numerals 119a and 119b represent adjusting screws for finely adjusting the tilt of the mirror supporter 107. A pipe 108 for cooling the mirror is inserted within the supporting rod 106. The pipe 108 for cooling the mirror communicates with a cooling channel 112 formed in the mirror holder 102. Reference numeral 113 represents an O-ring for sealing a connecting portion between the pipe 108 for cooling the mirror and the cooling channel 112. In order to prevent attenuation of synchrotron radiation light, the mirror 101 is provided in a vacuum. While light having longer wavelengths of light incident upon the mirror 101 is reflected by the mirror 101, light having shorter wavelengths is absorbed by the mirror 101, and the energy of the light is converted into heat. The temperature of the mirror 101 is raised by the heat, and the shape of the reflecting surface of the mirror 101 is deformed by thermal expansion, thereby causing uneven exposure. Accordingly, cooling means, comprising the pipe 108 for cooling the mirror, the cooling channel 112 and the like, is provided for the mirror 101 in order to conduct the heat to the outside. The cooling channel 112 is doubly sealed in order to prevent cooling water from leaking into the vacuum. The mirror 101 is indirectly cooled by cooling the mirror holder 102, which includes the cooling channel 112. Since the interface between the mirror holder 102 and the mirror 101 is in the vacuum, thermal contact resistance is produced. However, the above-described conventional approach has the following problems. That is, in order to cool the mirror provided within the vacuum chamber, it is necessary to provide the mirror holder, in which the cooling channel for circulating cooling water is provided, and the cooling-water pipe (the pipe for cooling the mirror) within the vacuum chamber. In order to facilitate positioning of the mirror, the mirror is coupled together with the mirror holder, on which the mirror is mounted. Accordingly, every time the mirror is exchanged, the pipe for cooling the mirror must be connected within the vacuum chamber. This causes very inferior operability for exchanging the mirror, and provides for inferior operability overall. Since leakage of cooling water within the vacuum chamber greatly degrades the degree of vacuum of the vacuum chamber, sufficient countermeasures must be provided in order to prevent leakage of the cooling water. As a result, the configuration of the vacuum chamber becomes complicated, thereby impairing the ease of maintenance and increasing the cost of the apparatus. In addition, an interface between the mirror and the cooling member (mirror holder) within the vacuum chamber produces thermal contact resistance, thereby reducing the cooling efficiency. Accordingly, there is room for improving the cooling efficiency. SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems. It is an object of the present invention to provide a mirror unit having a small size, an excellent cooling efficiency, ease of exchange, and an excellent maintenance capability, and an exposure apparatus which includes the mirror unit. According to one aspect, the present invention, which achieves the above-described object, relates to a mirror unit, comprising a mirror having a reflecting surface, a holding member for supporting the mirror and an airtight chamber incorporating the mirror, supported by the holding member, in an airtight state. One of the mirror and the holding member constitutes a portion of a side wall of the airtight chamber. The mirror unit can be suitably used in an exposure apparatus which uses a synchrotron radiation light source or the like as a light source. According to another aspect, the present invention relates to an exposure apparatus, comprising a light source for generating a radiation beam, a mirror unit including a mirror for reflecting the radiation beam, and an exposure unit for exposing a substrate with the reflected radiation beam. The mirror unit comprises a mirror having a reflecting surface, a holding member for supporting the mirror and an airtight chamber incorporating the mirror, supported by the holding member, in an airtight state. One of the mirror and the holding member constitutes a portion of a side wall of the airtight chamber. The foregoing and other objects, advantages and features of the present invention will become more apparent from the following description of the preferred embodiments taken in conjuction with the accompanying drawings.
054540216	summary	BACKGROUND OF THE INVENTION This invention relates to an x-ray mirror and material such as a total reflection mirror and a multilayer mirror reflective in the x-ray wavelength region. In a catoptric system wherein the wavelength of the x-ray region, 0.1 .ANG. to 200 .ANG., is employed, a total reflecting mirror, a multilayer mirror, and so on are used depending on the use and the wavelength. If radiation is incident at a small oblique angle, the mirror of the catoptric system has an increased area and on the other hand the mirror of an optical system for a focusing and an imaging mirror has a reduced aperture and thereby an increased aberration. Therefore, it is preferable that the critical angle of x-ray radiation to the mirror surface in total reflection be large. As regards reflecting material, high density substances such as Au and Pt are used because the critical angle of total reflection is in proportion to the density of the reflecting material. Au and Pt are chemically quite stable, and are thereby utilized for the reflecting surface because of the excellence of their reflecting property. In these reflecting mirrors, materials such as Au and Pt are deposited on a surface of a support substrate made of a material such as quartz glass, monocrystalline silicon, and SiC which can be polished to a very level form, by physical or chemical vapor deposition such as vacuum deposition and sputtering, or plating. X-rays have a short wavelength, which is about 1/10-1/1000 of that of visible light. So, in order to obtain highly efficient reflectance in this wavelength region, the roughness of the reflecting surface and of the interface with the reflecting material support substrate must be reduced to about 1/10-1/1000 of that for visible light. Also in a substrate, such as one made of quartz glass, polished to have a level surface, the roughness of the film surface could be increased during deposition. Particularly, substances such as Pt and Au are low in Debye temperature and thereby the mobility of atoms at room temperature is large. As a result, crystal grains grows during vacuum deposition and sputtering, which will cause the roughness of the surface to increase. Further, a film 100-1000 .ANG. thick is deposited to form a total reflecting mirror. The film thickness of one layer of a multilayer mirror is between 10 .ANG. and 100 .ANG.. If the film is formed by the above-mentioned method, the density of the film tends to be reduced by about 5-30% as compared to that of a bulk material with the above film thickness. Therefore, x-ray reflecting performance can not be sufficiently obtained. SUMMARY OF THE INVENTION An object of the present invention is to reduce the surface roughness of a Pt film formed by the above deposition method and provide a reflecting material for an x-ray mirror which has a density almost equal to that of a pure Pt film, which is superior in reflecting property and which is chemically stable. The above and other objects are achieved, according to the present invention, by providing a reflecting material constituted by a film of an alloy whose composition is expressed by the general formula Pt.sub.1-x M.sub.x, for a mirror surface of an x-ray mirror so as to reduce the surface roughness without significantly reducing the film density. However, M is one or more of the following substances; Mo, Ru, Rh, Pd, Ta, W, and Au. Preferably, x satisfies the equation; 0.005.ltoreq..times..ltoreq.0.10. If x is expressed as a percentage, then x is between 0.5% and 10% and the formula is expressed as Pt.sub.100-x M.sub.x. When M, as defined above, is added to Pt in a proportion of 0.5-10%, the crystal grain size of an alloy film according to the present invention becomes much smaller than that of a conventional pure Pt film. Further, dispersion of the crystal grain size and surface roughness both decrease. However, the film density does not decline significantly since the quantity of the additive is small. Hence, x-ray reflecting performance is improved. If M is added in a total proportion of more than 10%, surface roughness increases and film density decreases. Consequently the x-ray reflecting performance declines.
	summary
	description	This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 2006-275543 filed in Japan on Oct. 6, 2006, the entire contents of which are hereby incorporated by reference. The present invention relates to a mesh for holding a sample when the sample is observed by a microscope and a method of observing a rubber slice used as the sample by holding the rubber slice by the mesh, and more particularly to a mesh capable of observing a rubber slice in a stretch process and the rubber slice both in the stretch process and a contraction process. In observing a sample with a microscope such as a transmissive electron microscope (TEM), after the sample is thinned with a cutting device, the thinned sample is fixed to a sample-supporting material called a mesh. After the mesh is fixed to the exclusive sample holder, the sample is observed. Normally, a disk-shaped mesh 1 having a diameter of about 3 mm has reticulate openings 2, narrow groove-shaped openings 3, and a single hole 4 as shown in FIG. 10 so that the mesh 1 is capable of transmitting electron beams therethrough. As shown in FIG. 11, a thinned sample 4 is fixed to an upper surface of a central portion of the mesh 1 having openings 3 formed therethrough. It is necessary to thin the sample to such an extent that the sample is capable of transmitting electron beams therethrough. It is known that the sample is thinned by using a device called a microtome and that a specific portion of the sample is thinned by using a focused ion beam processing method (FIB processing). In Japanese Patent Application Laid-Open No. 11-329325, a mesh having a specific configuration suitable for the FIB processing is proposed. When the sample is made of rubber, observing a rubber slice undergoing a stretch process and the rubber slice undergoing the stretch process and thereafter a contraction process (return step) is useful for analyzing breakage, damage, deterioration, and wear of rubber and the mechanism of the generation of hysteresis loss and is also useful for making a combined design based on these analyses. It is almost impossible to stretch a conventional mesh to which the sample is fixed, which makes it impossible to observe the rubber slice in a stretched state. Even though the mesh is forcibly stretched, it has a slight stretched amount and remains deformed as a result of the stretching. Thus it is impossible to return the rubber slice stretched on the mesh to its original state and observe the rubber slice in the contraction process (return step). Patent document: Japanese Patent Application Laid-Open No. 11-329325 The present invention has been made in view of the above-described problems. It is an object of the present invention to provide a mesh allowing a rubber slice to be observed in a stretch process and in addition both in the stretch process and a contraction process and a method of observing the rubber slice by using the mesh. To solve the above-described problem, the first invention provides a mesh supporting a rubber slice in a stretch process so that the rubber slice can be observed by a microscope, wherein an upper surface of a central portion of the mesh is set as a placing region to which the rubber slice is fixed; left and right sides of the mesh sandwiching the placing region therebetween are set as left and right to-be-fixed portions to be fixed to sample holder separation portions respectively to be moved in a stretch direction; and a slit for opening use is formed by cutting the mesh in a required length from an outer edge thereof disposed between the left and right to-be-fixed portions in a direction orthogonal to the stretch direction or a direction inclined thereto. In this construction, when the to-be-fixed portions are moved in a separation direction by moving the sample holder separation portions, the slit for opening use is opened toward the outer edge of the mesh to stretch the mesh in the stretch direction so that the rubber slice, left and right sides of which have been fixed to the to-be-fixed portions respectively is stretched. In the above-described construction, the slit for opening use is formed by cutting the mesh in the required length from a portion of its periphery disposed between its left and right to-be-fixed portions in the direction orthogonal to the stretch direction or the direction inclined thereto. Therefore by separating the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively from each other and moving the sample holder separation portions in the stretch direction, the mesh is uniformly stretched in the stretch direction while the slits for opening use is being opened, and the rubber slice fixed to the mesh is also stretched, as the mesh is stretched. Accordingly by only moving the sample holder separation portions to which the left and right sides of the mesh have been fixed in the stretch direction, it is possible to stretch the rubber slice at any desired degree of stretching and directly observe the state of the rubber slice at any desired degree of stretching. Thereby it is possible to observe the change of the state (morphology change) of the rubber slice in the stretch process. The dimension, position, number, and cutting direction of each slit for opening use is not restricted specifically respectively, provided that the rubber slice on the mesh can be stretched by extending the mesh in the stretch direction, but appropriately set according to the configuration of the opening of the mesh, the configuration of the rubber slice fixed onto the mesh, and the fixing position of the rubber slice. But to allow the slits for opening use to be uniformly extended in the left-to-right direction about the center of the mesh, it is preferable that the left side of the slit for opening use and the right side thereof are disposed symmetrically with respect to the center of the mesh. To extend the mesh in the stretch direction by opening the slit for opening use, it is preferable to form a plurality of the slits for opening use from upper and lower outer edges of the mesh with the upper and lower slits for opening use alternating with each other. The second invention provides a mesh supporting a rubber slice in a stretch process and a contraction process so that the rubber slice can be observed by a microscope. An upper surface of a central portion of the mesh is set as a placing region, having an opening, to which the rubber slice is fixed; left and right sides of the mesh sandwiching the placing region therebetween are set as left and right to-be-fixed portions to be fixed to sample holder separation portions to be moved in a stretch direction; and a slit for dividing use is formed by cutting the mesh from an outer edge thereof disposed between the left and right to-be-fixed portions toward the rubber slice-placing region in a direction orthogonal to the stretch direction or a direction inclined thereto. In this construction, when the to-be-fixed portions are moved in a separation direction by moving the sample holder separation portions, the rubber slice, left and right sides of which have been fixed to the to-be-fixed portions respectively divided by the slit for dividing use is stretched; and when the to-be-fixed portions are moved from a stretched position in an approach direction by moving the sample holder separation portions, the rubber slice is contracted. In the above-described construction, the mesh has the slit for dividing use formed from a portion of its periphery disposed between the left and right to-be-fixed portions of the mesh to be fixed to the sample holder separation portions respectively toward the rubber slice-placing position of the mesh in the direction orthogonal to the stretch direction of the rubber slice or the direction inclined thereto. Therefore by moving the sample holder separation portions which are provided on the sample holder and to which the left and right sides of the mesh have been fixed respectively in the stretch direction, the mesh is divided into the left and right parts in the stretch direction and moved away from each other. The rubber slice fixed to the left and right parts of the mesh is stretched uniformly in the stretch direction owing to the division of the mesh and move-away of the left and right parts thereof. Thus by only moving the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively in the stretch direction, it is possible to stretch the rubber slice at any desired degree of stretching without deforming the mesh and directly observe the state of the rubber slice at any desired degree of stretching. Thereby it is possible to observe the change of the state (morphology change) of the rubber slice in the stretch process. When the sample holder separation portions are moved in the contraction direction in which the left and right to-be-fixed portions are approached to each other, the divided left and right parts of the mesh approach to each other and finally can be restored to the original undivided state without the mesh remaining strained. Therefore it is possible to restore the rubber slice to the state before it is stretched and observe the state of the rubber slice not only in the stretch process but also in the contraction process (return process). As described above, when the slit for dividing use is formed in the direction orthogonal to the stretch direction or the direction inclined thereto, it is possible to stretch the rubber slice in the stretch direction by dividing the mesh. But to form the slit for dividing use in the direction orthogonal to the stretch direction is simplest and allows the rubber slice to be uniformly stretched in the stretch direction. When the slit for dividing use is formed by inclining it to the stretch direction, it is especially preferable to incline the slit for dividing use not less than 10 degrees to the stretch direction. A reticulate opening or a narrow groove-shaped opening is formed in the rubber slice-placing region. The slit for opening use or the slit for dividing use is formed in a peripheral portion of the mesh surrounding the reticulate opening or the narrow groove-shaped opening by cutting the mesh from the outer edge thereof. As described above, the mesh may have the reticulate opening or the narrow-groove-shaped opening formed at the rubber slice-placing position. In the case of the mesh having the reticulate opening formed therethrough, unless the slit for opening use or the slit for dividing use is formed not only in the peripheral portion of the mesh constructing the peripheral frame thereof but also in the peripheral portion of thread surrounding the reticulate opening, it is often difficult to extend the mesh in the stretch direction or divide the mesh into the left and right parts by opening the slit for opening use. In the case of the mesh having the narrow-groove-shaped opening formed therethrough, by forming one slit for opening use at each of upper and lower positions of the mesh sandwiching the narrow-groove-shaped opening therebetween, it is possible to greatly extend the mesh in the stretch direction. The slit for dividing use is formed by traversing the placing region through the opening. For example, by only forming one slit for dividing use at the upper and peripheral portions of the mesh surrounding the narrow-groove-shaped opening, the mesh can be divided into left and right parts. In forming the slit for dividing use through the mesh, when the mesh is moved in the stretch direction to divide it into the left and right parts, an opening is generated between the separated left and right parts of the mesh. Therefore the reticulate opening and the narrow-groove-shaped opening do not necessarily have to be formed in the placing region. The mesh of each of the first and second inventions can be used especially preferably for a transmissive electron microscope (TEM) and a scan type electron microscope (SEM) and in addition for a scan type probe microscope (SPM), a laser microscope, and an optical microscope. The third invention provides a method of observing a rubber slice, wherein the rubber slice fixed to the rubber slice-placing region of the mesh is stretched by moving the sample holder separation portions to which left and right sides of the mesh of the first invention have been fixed respectively in a stretch direction so that the rubber slice in a stretch process is observed by a microscope. In the third invention, by using the mesh of the first invention through which the slit for opening use is formed by cutting the mesh, the rubber slice is stretched by opening the slit for opening use and extending the mesh in the stretch direction. Therefore as the mesh is extended, the mesh remains deformed to some extent. Thus the third invention is not suitable for observing the rubber slice in the contraction process but suitable for observing the rubber slice in the stretch direction. The fourth invention provides a method of observing a rubber slice, wherein by moving sample holder separation portions to which left and right sides of the mesh of the second invention have been fixed respectively in a stretch direction, the rubber slice fixed to a rubber slice-placing region of the mesh is stretched to observe the rubber slice in a stretch process by a microscope, and thereafter by moving the sample holder separation portions in a contraction direction, the rubber slice fixed to the rubber slice-placing region of the mesh is contracted so that the rubber slice in a contraction process is observed by a microscope. In the fourth invention, by dividing the mesh of the second invention through which the slit for dividing use is formed into two parts and moving the two parts away from each other, the rubber slice is stretched. Thus the mesh does not remain deformed. Therefore it is possible to observe the rubber slice not only in the stretch process but also in the contraction process (return process), which is useful for analyzing the breakage, damage, deterioration, and wear of rubber, the mechanism of reinforcing a polymer, a filler, and the like, and the analysis of the mechanism of the generation of hysteresis loss, and for making a combined design based on these analyses. It is preferable to form the slit for opening use of the mesh and the slit for dividing use thereof used in the method of the third and fourth inventions of observing the rubber slice by cutting the mesh with razor, surgical knife, cutter or the like after the rubber slice is fixed to the upper surface of the central portion of the mesh. Thereby it is easy to handle the mesh because the mesh is not divided into a large number of pieces before the mesh is stretched and possible to fix the rubber slice to the mesh in a stable state. As described above, according to the first invention, the slit for opening use is formed by cutting the mesh in the required length from the outer edge thereof disposed between its left and right to-be-fixed portions in the direction orthogonal to the stretch direction or the direction inclined thereto. Therefore by moving the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively in the stretch direction, the mesh is uniformly stretched in the stretch direction while the slits for opening use is being opened, and the rubber slice fixed to the mesh is also stretched, as the mesh is stretched. Accordingly by moving the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively in the stretch direction, it is possible to stretch the rubber slice at any desired degree of stretching and directly observe the state of the rubber slice, as the third invention provides. According to the second invention, the mesh has the slit for dividing use formed from a portion of its periphery disposed between the left and right to-be-fixed portions of the mesh to be fixed to the sample holder separation portions respectively toward the rubber slice-placing position of the mesh in the direction orthogonal to the stretch direction of the rubber slice or the direction inclined thereto. Therefore by moving the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively in the stretch direction, the mesh is divided into the left and right parts in the stretch direction. The rubber slice fixed to the left and right parts of the mesh is stretched uniformly in the stretch direction owing to the division of the mesh and the move-away of the left and right parts thereof. Thus by only moving the sample holder separation portions to which the left and right sides of the mesh have been fixed respectively in the stretch direction, it is possible to stretch the rubber slice at any desired degree of stretching without deforming the mesh and directly observe the rubber slice in the stretch process. When the sample holder separation portions are moved in the contraction direction, the divided left and right parts of the mesh approach to each other and finally can be restored to the original undivided state without the mesh remaining strained. Therefore it is possible to restore the rubber slice to the state before it is stretched and observe the state of the rubber slice not only in the stretch process but also in the contraction process (return process), as the fourth invention provides. The embodiments of the present invention are described below with reference to the drawings. FIGS. 1 through 5 show the first embodiment of the present invention. A mesh 11 of the first embodiment has narrow groove-shaped openings 11a in a placing region 11b where a rubber slice 10 is placed and slits 12a, 12b for dividing use communicating with the narrow groove-shaped openings 11a. That is, after the rubber slice 10 to be used as a sample shown in FIG. 2 is fixed to the mesh-placing region 11b disposed on an upper surface of the center of the mesh 11 which has three narrow groove-shaped openings 11a at the center thereof, as shown in FIGS. 3 and 4, the slits 12a, 12b for dividing use are sequentially formed on the mesh 11 by using a cutting blade (razor in the first embodiment). Making detailed description, initially the thinned rubber slice 10 (1 mm (length)×2 mm (width)×200 nm (thickness)) is made from a rubber composition having components mixed at ratios shown in table 1 by using a microtome (not shown, commercial name: Ultramicrotome EM VC6, produced by LEICA Inc.). The rubber slice 10 is placed on and fixed to the mesh-placing region 11b which is disposed on the upper surface of the center of the mesh 11 (diameter: 3 mm) which has the three narrow groove-shaped openings 11a (11a-1, 11a-2, and 11a-3) shown in FIG. 1 by using an exclusive loop (not shown) with the rubber slice 10 straddling over the three narrow groove-shaped openings 11a (FIG. 2). TABLE 1Mixing amountCompounding components(part by weight)Styrene butadiene rubber100Carbon black (N220)70Sulfur1.5Zinc oxide3Accelerator B1 As shown in FIG. 4, the mesh 11 is placed on a sample holder 13. Both left and right sides (to-be-fixed portion 11d, 11e) of the mesh 11 are fixed to hold-down plates 13a-1, 13b-1 of sample holder separation portions 13a, 13b by screws 13a-2, 13b-2. The slits 12a, 12b for dividing use are formed by cutting upper and lower centers of a peripheral frame 11c surrounding the narrow groove-shaped opening 11a of the mesh 11 in a direction orthogonal to a stretch direction (left-to-right direction) of the rubber slice 10 by using a cutting blade (not shown). In this manner, the mesh of the first embodiment is obtained. That is, the slits 12a, 12b for dividing use are formed by cutting the peripheral frame 11c continually with the central opening 11a-2 of the three narrow groove-shaped openings 11a. As described above, the slits 12a, 12b for dividing use are formed at the upper and lower peripheral portions of the central opening 11a-2 of the mesh 11. The slit 12a for dividing use, the opening 11a-2, and the slit 12b for dividing use are traversed through a placing portion where the rubber slice 10 is placed to form a division line SL. Thereby the mesh 11 is divided into left and right parts 11A, 11B. The slits 12a, 12b for dividing use are located at the upper and lower positions in the drawings. Because the mesh 11 is horizontally disposed, the slits 12a, 12b for dividing use are located at front and rear sides of the horizontally disposed opening 11a-2. As described above, the left and right parts 11A, 11B of the mesh 11 formed by dividing the mesh 11 at the division line SL formed as the boundary are fixed to the sample holder separation portions 13a, 13b respectively. Thus when the sample holder separation portions 13a, 13b are separated from each other by moving them in the stretch direction, the width of the division line SL gradually increases. As a result, the rubber slice 10 whose left and right sides have been fixed to the left and right parts 11A, 11B of the mesh 11 are stretched in the left-to-right direction in the drawing. In the process of observing the rubber slice 10 with a microscope, the sample holder 13 to which the mesh 11 has been fixed is set on a transmissive electron microscope (not shown) (H7100 produced by Hitachi Co., Ltd., acceleration voltage 100 KV) to observe the rubber slice 10 having a degree of stretching at 0%. Thereafter the rubber slice 10 is stretched by moving the sample holder separation portion 13b of both sample holder separation portions 13a, 13b to which the left and right sides 11d, 11e of the mesh 11 have been fixed respectively in the stretch direction (direction shown by an arrow A) to observe the rubber slice 10 having the degree of stretching at 50%, 100%, and 150% in a stretch process. After the rubber slice 10 in the stretch process is observed, the left and right parts 11A, 11B of the mesh 11 are approached to each other by moving the sample holder separation portion 13b in a direction shown with an arrow B to contract the rubber slice 10 so that the rubber slice 10 having the degree of stretching at 100%, 50%, and 0% in a contraction process (return process) is observed. As described above, the mesh 11 of the present invention has the slits 12a, 12b for dividing use formed from a portion of its periphery disposed between the left and right to-be-fixed portions 11d, 11e of the mesh 11 to be fixed to the sample holder separation portions 13a, 13b respectively toward the rubber slice-placing position 11b of the mesh 11 in the direction orthogonal to the stretch direction (left-to-right direction) of the rubber slice 10. Therefore by moving the sample holder separation portion 13b of the sample holder separation portions 13a, 13b to which the left and right sides 11d, 11e of the mesh 11 have been fixed respectively in the stretch direction (the direction shown by the arrow A), the mesh 11 is divided into the left and right parts 2A, 2B. The rubber slice 10 fixed to the left and right parts 2A, 2B of the mesh 11 is stretched uniformly in the stretch direction owing to the division and move-away of the mesh 11. Thus by only moving the sample holder separation portion 13b of the sample holder separation portions 13a, 13b to which the left and right sides 11d, 11e of the mesh 11 have been fixed respectively in the stretch direction, it is possible to stretch the rubber slice 10 at a desired degree of stretching without deforming the mesh 11 and directly observe the rubber slice 10 in the stretch process. By moving the sample holder separation portion 13b in the contraction process (direction shown with an arrow B) subsequently to the stretch process, the left and right parts 2A, 2B of the mesh 11 formed by dividing the mesh 11 are approached to each other and finally can be restored to the original undivided state without the mesh 11 remaining strained. Therefore it is possible to restore the rubber slice 10 to the state before it is stretched and observe the state of the rubber slice 10 not only in the stretch process but also in the contraction process (return process). The result of the observation of the rubber slice 10 in the stretch process and the contraction process (return process) is as described below. That is, at 0% in the degree of stretching, the aggregation of a filler was observed. As the rubber slice 10 was stretched, initially, aggregated units of filler particles started to deform. When the degree of stretching exceeded 100%, deformation of each particle was observed. Separation was observed in a filler having a large stress concentration and on the interface of a polymer. It was also revealed that the filler did not stretch uniformly but stepwise changes occurred according to each strain. When the degree of stretching was returned to 0% in the contraction process, a process of return to the original aggregated structure was observed. FIGS. 6(A) through 6(C) show modifications of the first embodiment. In FIG. 6(A), an opening is not formed on the mesh 11 at the position where the rubber slice is placed, but only one slit 12-1 for dividing use is formed on the mesh 11 in the direction orthogonal to the stretch direction. In FIG. 6(B), only one slit 12-2 for dividing use is formed on the mesh 11 by inclining it at an angle of α of 10 degrees to the stretch direction. By providing the mesh 11 with the slit for dividing use, an opening is generated between divided parts of the mesh. Thus the opening does not necessarily have to be formed. In the mesh 11 shown in FIG. 6(C), the peripheral frame 11c holds reticulate lines 100 consisting of fibers to form narrow groove-shaped openings 100a. In the mesh 11, slits 12-3 for dividing use are formed through the peripheral frame 11c and the reticulate lines 100. FIG. 7 shows a second embodiment. A mesh 14 of the second embodiment has one narrow groove-shaped opening 14a formed by cutting a lower side of a peripheral frame 14c. One slit 15 for dividing use is formed at an upper side of the peripheral frame 14c to form the division line SL of the narrow groove-shaped opening 14a and the slit 15 for dividing use. After left and right sides 14d, 14e of the mesh 14 are fixed to the sample holder separation portions 13a, 13b, respectively with the rubber slice 10 fixed to the mesh 14, the slit 15 for dividing use is formed in the direction orthogonal to the stretch direction (left-to-right direction). In the second embodiment, by the movement of the sample holder separation portion 13b in the stretch direction, the mesh 14 is divided into left and right parts, and without deforming the mesh 14, the rubber slice 10 can be stretched uniformly in the stretch direction. Therefore similarly to the first embodiment, the rubber slice 10 in the stretch process and the contraction process (return process) can be observed. FIG. 8 shows a third embodiment. In a mesh 16 of the third embodiment, slits 17a, 17b, and 17c for opening use are alternately formed at upper and lower positions of a peripheral frame 16c surrounding a narrow groove-shaped opening 16a in the direction orthogonal to the stretch direction (left-to-right direction) of the rubber slice 10 to such an extent that the slits 17a, 17b, and 17c for opening use do not communicate with the narrow groove-shaped opening 16a. The slits 17a, 17b, and 17c for opening use are formed after the left and right sides 16d, 16e of the mesh 16 are fixed to the sample holder separation portions 13a, 13b respectively with the rubber slice 10 fixed to the mesh 16. Other constructions of the third embodiment are similar to those of the first embodiment. According to the above-described construction, the mesh 11 has the slits 17a, 17b, and 17c for opening use formed vertically and alternately on the peripheral frame 16c disposed between the left and right to-be-fixed portions 16d, 16e of the mesh 16 to be fixed to the sample holder separation portions 13a, 13b respectively in the direction orthogonal to the stretch direction (left-to-right direction). Therefore by moving the sample holder separation portion 13b of the sample holder separation portions 13a, 13b to which the left and right sides 16d, 16e of the mesh 16 have been fixed respectively in the stretch direction (the direction shown by the arrow A), the mesh 16 is stretched in the stretch direction, while the slits 17a, 17b, and 17c for opening use are being opened, and the rubber slice 10 fixed to the mesh 16 is also stretched, as the mesh 16 is stretched. Thus by only moving the sample holder separation portion 13b of the sample holder separation portions 13a, 13b to which the left and right sides 16d, 16e of the mesh 16 have been fixed respectively in the stretch direction, it is possible to stretch the rubber slice 10 at a desired degree of stretching and directly observe the rubber slice 10 in the stretch process. When the sample holder separation portions 13a, 13b are moved to each other in the approach direction after they are moved away from each other in the stretch direction, the rubber slice 10 is strained unless the shrinkage factor of the mesh 16 and that of the rubber slice 10 are equal to each other. Therefore it is impossible to use the mesh 16 having the slit for opening use to observe the rubber slice 10 in the contraction process. When the shrinkage factor of the mesh 16 having the slit for opening use is approximately equal to that of the rubber slice 10, the mesh 16 having the slit for opening use can be used in the contraction process. FIGS. 9(A) and 9(B) show modifications of the third embodiment. In the mesh 16 of FIG. 9(A), a large number of narrow groove-shaped openings 16a is formed side by side in the central portion of the mesh 16 in the left-to-right direction, and slits for opening use 17 are formed alternately at upper and lower portions of the narrow groove-shaped openings 16a. In the mesh 16 of FIG. 9(B), openings are not formed, but a slit for opening use 17e is formed by cutting the mesh 16 from an upper peripheral edge of the mesh 16, whereas a slit for opening use 17f is formed by cutting the mesh 16 from a lower peripheral edge of the mesh 16 with a sphere formed at a leading end of each of the slits 17e, 17f. By spherically forming the leading end thereof, it is possible to prevent the mesh 16 from being twisted when the mesh 16 is stretched. In any of the above-described embodiments, after the rubber slice is fixed to the mesh, the slit is formed. But if the position where the slit for opening use is formed does not interfere with the region of the mesh 16 where the rubber slice 10 is placed, the slit may be formed through the mesh 16 before the rubber slice 10 is placed on and fixed to the mesh 16. The mesh of the present invention is preferably used to hold the rubber slice in observing the state of the rubber slice in the stretch process and the contraction process. In addition to the rubber slice, the mesh of the present invention can be also used to observe a sample to be stretched, for example, a film made of resin in the stretch direction and the contraction process. The mesh of the present invention is preferably used as a sample-holding material in observing a sample by a scan type electron microscope, a transmissive electron microscope, a scan type probe microscope, a laser microscope, and an optical microscope.
046997563	description	DETAILED DESCRIPTION OF THE INVENTION In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are to be construed as limiting terms. In General Referring now to the drawings, and particularly to FIG. 1, there is shown an elevational view of a fuel assembly, represented in vertically foreshortened form and being generally designated by the numeral 10. The fuel assembly 10 basically includes a lower end structure or bottom nozzle 12 for supporting the assembly on the lower core plate (not shown) in the core region of a reactor (not shown), and a number of longitudinally extending guide tubes or thimbles 14 which project upwardly from the bottom nozzle 12. The assembly 10 further includes a plurality of transverse grids 16 axially spaced along the guide thimbles 14 and an organized array of elongated fuel rods 18 transversely spaced and supported by the grids 16. Also, the assembly 10 has an instrumentation tube 20 located in the center thereof and an upper end structure or top nozzle 22 attached to the upper ends of the guide thimbles 14. With such an arrangement of parts, the fuel assembly 10 forms an integral unit capable of being conventionally handled without damaging the assembly parts. As mentioned above, the fuel rods 18 in the array thereof in the assembly 10 are held in spaced relationship with one another by the grids 16 spaced along the fuel assembly length. Each fuel rod 18 includes nuclear fuel pellets 24 and the opposite ends of the rod are closed by upper and lower end plugs 26,28 to hermetically seal the rod. Commonly, a plenum spring 30 is disposed between the upper end plug 26 and the pellets 24 to maintain the pellets in a tight, stacked relationship within the rod 18. The fuel pellets 24 composed of fissile material are responsible for creating the reactive power of the nuclear reactor. A liquid moderator/coolant such as water, or water containing boron, is pumped upwardly through the fuel assemblies of the core in order to extract heat generated therein for the production of useful work. To control the fission process, a number of control rods 32 are reciprocally movable in the guide thimbles 14 located at predetermined positions in the fuel assembly 10. Specifically, the top nozzle 22 includes a rod cluster control mechanism 34 having an internally threaded cylindrical member 36 with a plurality of radially extending flukes or arms 38. Each arm 38 is interconnected to a control rod 32 such that the control mechanism 34 is operable to move the control rods 32 vertically in the guide thimbles 14 to thereby control the fission process in the fuel assembly 10, all in a well-known manner. Control Rod with Axially Inhomogeneous Absorber Material Turning now to FIG. 2, there is shown the improved control rod of the present invention, generally designated 40, which is adapted to be used in EOL leading up to reactor shutdown. For example, at the fifteen year control rod changeover of some reactor cores, the control rods 32 used in earlier core cycles would be replaced by the control rod 40 of the present invention. The improved control rod 40 which employs axially inhomogeneous absorber material basically includes an elongated hollow tubular member 42 having upper and lower opposite ends 44,46 and a hermetically sealed chamber 48 defined within the tubular member between its opposite ends. The lower end 46 is the leading end, whereas the opposite upper end 44 is the trailing end of the member 42 upon insertion of the control rod 40 into the fuel assembly 10. Further, the control rod 40 includes a first neutron absorber material 50, preferably in the form of pellets of boron carbide, contained in the chamber 48 and located nearer to the upper trailing end 44 than to the lower leading end of the tubular member 42. Also, a second neutron absorber material 52, preferably in the form of pellets of silver-indium-cadmium, is contained in the chamber 48 and located nearer to the lower leading end 46 than to the upper trailing end 44 of the tubular member 42. The first neutron absorber material 50 (boron carbide) has a higher neutron absorption cross section absorbing capacity than that of the second neutron absorber material 52 (silver-indium-cadmium), specifically approximately twenty-five percent higher. Further, the second neutron absorber material 52 is greater in quantity than that of the first neutron absorber material 50. In particular, the quantities of the first and second neutron absorber materials 50,52 are represented by the respective lengths thereof. The length of the second material 52 is approximately three times longer than that of the first material 50. That is, the first absorber material 50 extends the upper approximately twenty-five percent of the combined length of the absorber material within the tubular member chamber 48, whereas the second absorber material 52 extends the lower approximately seventy-five percent of the combined length. Thus, the second neutron absorber material 52 has a length approximately three times longer than that of the first neutron absorber material 50. Like other control rods, the tubular member 42 of the improved control rod 40 is formed by an elongated, thin-walled metallic cladding or tube 54 having respective upper and lower end plugs 56,58 for sealing the opposite upper and lower ends 44,46 of the member 42. The upper end plug 56 has an upwardly extending integrally formed stem section with an externally threaded end 60 for connection to the control mechasism 34. The lower end plug 58 is cone-shaped. The absorber material pellets 52,50 which, as seen in FIG. 2, preferably have the same diameter, are slidably disposed within the chamber 48 and rest on the lower end plug 58 in a tandemly arranged stack. A plenum spring 62 is interposed between the upper end of the pellet stack and the upper end plug 56 to maintain an axial spaced relationship therebetween to define a space within the tubular member 42 for receiving gases generated by the pellets 50,52 as they absorb neutrons in the control reaction. Since the boron carbide absorber material is just in the upper twenty-five percent of the absorber material, there is essentially no concern with boron carbide swelling, since it never enters the core until the reactor is at low power or shutdown. Also, there will be no impact on rodded peaking factor at high power level either because (a) rods are not allowed to be inserted deeply, and (b) the same material, i.e., silver-indium-cadmium in this case, is not changed from what is used previously for a particular reactor. It is thought that the improved control rod of the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.
	claims	1. A target assembly for a nuclear reactor, the target assembly comprising:a solid annulus comprising uranium, and defining an outer circumference and an inner circumference, the inner circumference defining a volume within the solid annulus;a solid target material within the volume of the annulus, the solid target material consisting essentially of non-uranium material and comprising at least one of Mo, P, S, Ir, Au, Re, and/or Cr;the solid target material consisting of a plurality of longitudinally stacked nuclear fuel pellets;at least one liner arranged along the inner circumference of the solid annulus, the at least one liner operable to absorb thermal neutrons and allow epithermal and fast neutrons to selectively pass to the target material during irradiation;wherein the solid target material spans the volume defined by the at least one liner; andwherein the solid annulus is configured to be distinct from and removably coupled to the solid target material following irradiation. 2. The target assembly of claim 1 further comprising one or more reflector components arranged along a perimeter of one or both of the solid target material and solid annulus. 3. The target assembly of claim 2 wherein the one or more reflector components comprise beryllium (Be) or lead (Pb). 4. The target assembly of claim 2 wherein the one or more reflector components, in at least one cross section, defines a thickness less than about 1 cm. 5. The target assembly of claim 1 wherein the at least one liner comprises one or more of boron, boron carbide, boron nitride, and cadmium. 6. The target assembly of claim 1 further comprising cladding over at least a portion of a surface of one or both of the solid annulus and solid target material. 7. The target assembly of claim 6 wherein the cladding comprises one or more of zirconium, zircalloy and stainless steel. 8. The target assembly of claim 1 wherein the solid annulus comprises uranium having an enrichment of 235U of less than about 20%. 9. The target assembly of claim 1 wherein the solid annulus comprises an alloy of uranium and erbium. 10. The target assembly of claim 1 wherein the solid annulus comprises UZrH. 11. The target assembly of claim 1 wherein the solid annulus and solid target material are disposed within a can wall. 12. The target assembly of claim 1 configured as an element to be coupled with a plurality of other elements in a single assembly. 13. The target assembly of claim 1 wherein in at least one cross section the distance between the inner and outer circumference of the solid annulus is from about 100 μm to about 1 cm. 14. The target assembly of claim 1 wherein the solid annulus defines a length extending between opposing openings to the volume, the length being less than about 38 cm.
	abstract	An apparatus for imaging a field of view, according to an embodiment of the present invention, comprises an x-ray source positioned adjacent to the field of view, a source mask located between the x-ray source and the field of view having at least one source aperture defined therethrough, and an emission detector, such as a gamma camera, adjacent to the field of view. The apparatus may allow substantially concurrent x-ray imaging and gamma imaging of the field of view.
	summary
	summary
054992770	abstract	An enhanced decay heat removal system for removing heat from the inert gas-filled gap space between the reactor vessel and the containment vessel of a liquid metal-cooled nuclear reactor. Multiple cooling ducts in flow communication with the inert gas-filled gap space are incorporated to provide multiple flow paths for the inert gas to circulate to heat exchangers which remove heat from the inert gas, thereby introducing natural convection flows in the inert gas. The inert gas in turn absorbs heat directly from the reactor vessel by natural convection heat transfer.
	description	This is a Divisional Application of U.S. patent application Ser. No. 15/457,030, filed Mar. 13, 2017, now U.S. Pat. No. 10,643,754, issued May 5, 2020, which claims priority to U.S. Provisional Patent Application No. 62/308,188, filed on Mar. 14, 2016, titled “Burnable poison operated reactor using gadolinium loaded alloy for nuclear thermal propulsion passive reactivity control”; and U.S. Provisional Patent Application No. 62/308,191, filed on Mar. 14, 2016, titled “Hydrogen pressure operated system for passive reactivity adjustment,” the entire disclosures of which are incorporated by reference herein. This invention was made with government support under Contract No. SBIR 2015-I NNX15CC62P awarded by the National Aeronautics and Space Administration (NASA). The government has certain rights in the invention. The present subject matter relates to examples of nuclear thermal propulsion systems and nuclear reactor systems. The present subject matter also encompasses passive reactivity control of nuclear thermal propulsion reactors. Conventional chemical based propulsion systems commonly deployed in rockets rely on an oxidizer, such as oxygen, to generate a chemical reaction in order to create thrust. Nuclear thermal propulsion (NTP) systems have the potential to deliver thrust values that far exceed chemical based fuels. Typically, this is done by heating a propellant, typically low molecular weight hydrogen, to over 2,6000 Kelvin by harnessing thermal energy from a nuclear reactor. NTP is an appealing technology with prospects for becoming the propulsion system of choice for human missions beyond low earth orbit. Numerous mission architectures call NTP the preferred approach for a 2030s human Mars mission for its ability to produce significant amounts of thrust while operating at a high specific impulse. The design of NTP systems dates back to the Nuclear Engine for Rocket Vehicle Applications (NERVA) work done by NASA. The NERVA design typically consists of a small nuclear fission reactor, turbopump assembly (TPA), nozzle, radiation shield, assorted propellant lines, pressure vessel, and support hardware. Thermal energy gained by the propellant during an expansion cycle is used to power the rocket. In conventional NTP designs, control drums are used to adjust reactor reactivity. Unfortunately, reactivity control of NTP reactors through the use of the control drums can be problematic in terms of operating requirements and effect on the performance of the propulsion system. Hence, there is room for further improvement in NTP systems and devices that incorporate such NTP systems. The passive control technologies disclosed herein simplify the control of an NTP system and improve the overall performance during operation. With some of the passive control technologies, little to no active mechanical movement of circumferential control drums will be required for the majority of NTP operation. The passive control technologies mitigate the effect of the build-up of 135Xe, a powerful neutron poison, during operation. While the technologies disclosed are utilized with low-enriched uranium (LEU) NTP systems (e.g., graphite composite fuel and tungsten (W) CERMET fuel), the technologies have application to any moderated NTP system, including highly-enriched uranium (HEU) graphite composite fueled NTP reactor systems. An LEU system has 20% or lower 235U. A ceramic and metal matrix (CERMET) fuel can include (U, PuO2), (enriched U, UO2), or other fuels. In an example, a nuclear thermal propulsion system comprises a nuclear reactor core. The nuclear reactor core includes an array of fuel elements and an array of tie tubes adjacent the array of fuel elements. Each tie tube includes a propellant supply passage to flow a propellant, an inner tie tube layer surrounding the propellant supply passage, a moderator sleeve surrounding the inner tie tube layer, a propellant return passage surrounding the moderator sleeve, and an outer tie tube layer surrounding the propellant return passage. A burnable poison can be dispersed in the nuclear reactor core. For example, the burnable poison is dispersed in the array of fuel elements or the array of tie tubes. The burnable poison can include Gadolinium (Gd). The Gd can be dispersed in an alloy that forms the outer tie tube layer. The propellant can be hydrogen. The Gd dispersed in the outer tie tube layer alloy can be in a quantity greater than 0 parts per million (ppm) and less than one-thousand (1,000) ppm. The Gd in the outer tie tube layer alloy can be a natural isotopic composition or an enriched 157Gd isotope. The outer tie tube layer alloy can further include nickel, chromium, and iron. The outer tie tube layer alloy can further include molybdenum, niobium, cobalt, manganese, copper, aluminum, titanium, silicon, carbon, sulfur, phosphorus, and boron. The outer tie tube layer alloy can also be formed of zirconium or zirconium carbide. The array of fuel elements can include a graphite composite fuel formed of low-enriched uranium (LEU) having 20% or lower 235U. The array of fuel elements can include a tungsten ceramic and metal matrix (CERMET) fuel formed of low-enriched uranium (LEU) having 20% or lower 235U. The moderator sleeve can include a solid hydride. The Gd dispersed in the outer tie tube layer alloy can be in a quantity of 20 parts per million (ppm) to 200 ppm. Each tie tube can further comprise an inner gap between the inner tie tube layer and the moderator sleeve, a graphite insulation layer surrounding the outer tie tube layer, a medial gap between the outer tie tube layer and the graphite insulation layer, an outer gap surrounding the graphite insulation layer, a graphite sleeve surrounding the outer gap, and a coating formed of zirconium carbide or niobium carbide surrounding the graphite sleeve. The graphite insulation layer can include zirconium carbide (ZrC), titanium carbide, silicon carbide, tantalum carbide, hafnium carbide, ZrC—ZrB2 composite, or ZrC—ZrB2—SiC composite. The propellant supply passage, the inner tie tube layer, the moderator sleeve, the propellant return passage, and the outer tie tube layer can be radially arranged. A respective radial wall thickness of the outer tie tube layer can be less than the inner tie tube layer. The array of fuel elements can be interspersed with the array of tie tubes and each of the tie tubes can be in direct or indirect contact with at least one fuel element. A plurality of circumferential control drums can surround the array of fuel elements and the array of tie tubes to change reactivity of the nuclear reactor core. In one example, the burnable poison can include Gadolinium (Gd) and the Gd can be dispersed in an alloy that forms the inner tie tube layer. In on example, the burnable poison can include Gadolinium (Gd) and the Gd can be dispersed in each of the fuel elements. In one example, the moderator sleeve can be formed of zirconium hydride and the burnable poison can include Gadolinium (Gd). The Gd can be dispersed in the zirconium hydride that forms the moderator sleeve. In one example, the nuclear reactor core can further comprise at least one wire formed of an alloy that is housed inside the nuclear reactor core and separate from the array of fuel elements and the array of tie tubes. The burnable poison can include Gadolinium (Gd). The Gd can be dispersed in the at least one alloy wire. The nuclear thermal propulsion system can further comprise a propellant tank to store the propellant, a nuclear reactor core inlet directly or indirectly connected to the nuclear reactor core, and a propellant line directly or indirectly connected to the propellant tank to flow the propellant to the nuclear reactor core inlet. The nuclear thermal propulsion system can further comprise a propellant density control valve system directly or indirectly connected between the propellant line and the nuclear reactor core inlet to regulate density of the propellant flowing into the nuclear reactor core. The nuclear thermal propulsion system can further comprise a turbopump assembly comprising at least one turbopump that includes a turbine and a pump. The pump can be configured to cool the nuclear reactor core during a burn cycle by flowing the propellant from the propellant tank through the propellant line to the propellant density control valve system, and then through the nuclear reactor core inlet. The nuclear reactor core inlet can include a tie tube inlet to flow the propellant to the array of tie tubes and can be directly or indirectly connected to the propellant density control valve system and a respective propellant supply passage of a respective tie tube in the array of tie tubes. The pump can be further configured to flow the propellant through the tie tube inlet, through the respective propellant supply passage of the respective tie tube in the array of tie tubes, and then through a respective propellant return passage of the respective tie tube. The nuclear thermal propulsion system can further comprise a propellant heating line directly or indirectly connected to the turbine and the respective propellant return passage of the respective tie tube and a second propellant density control valve system directly or indirectly connected to the turbine and the nuclear reactor core inlet to regulate density of the propellant flowing back to the nuclear reactor core inlet. The pump can be configured to flow the propellant returned by the respective propellant return passage to the turbine via the propellant heating line. The turbine can be configured to flow the propellant back to the second propellant density control valve system and the nuclear reactor core inlet. The nuclear reactor core inlet can further include a fuel element inlet to flow the propellant to the array of fuel elements and can be directly or indirectly connected to the second propellant density control valve system and a respective propellant passage of a respective fuel element of the array of fuel elements. The turbine can be configured to flow the propellant to the second propellant density control valve system, through the fuel element inlet, and then through the respective propellant passage of the respective fuel element of the array of fuel elements. The nuclear thermal propulsion system can further comprise a pressure vessel housing the nuclear reactor core that can be directly or indirectly connected to the propellant density control valve system. The pressure vessel can include a pressure vessel inlet connected to the periphery of the pressure vessel that is outside of the nuclear reactor core and a pressure vessel outlet to return the propellant passing through the periphery of the pressure vessel. The nuclear thermal propulsion system can further comprise a propellant heating line directly or indirectly connected to the turbine and the pressure vessel outlet. The pump can be further configured to flow the propellant to the pressure vessel inlet, through the periphery of the pressure vessel, and then flow the returned propellant from the pressure vessel outlet to the turbine via the propellant heating line. The nuclear thermal propulsion system can further comprise a nozzle, a plurality of control drums, a neutron reflector, and a second propellant density control valve system. The second propellant density control valve system can be directly or indirectly connected between the propellant line and the pressure vessel inlet to regulate density of the propellant flowing into the nozzle, the periphery of the pressure vessel, the neutron reflector, and the plurality of control drums. The propellant density control valve system can include a regulator valve to adjust density of the propellant passing through the regulator valve from an initial density when entering the regulator valve to a regulated density when exiting the regulator valve. The propellant density control valve system can also include an actuator to actuate the regulator valve by adjusting the regulated propellant density upwards during each subsequent burn cycle to maintain constant reactivity at a beginning of each of the subsequent burn cycles. The actuator can be electric, mechanical, thermal, magnetic, or a combination thereof. The propellant density control valve system can further include a flow control circuit to control speed of the actuator. The flow control circuit can be a bleed-off circuit, a meter-out circuit, or a meter-in circuit. The regulator valve and the actuator can form a solenoid valve or an electrohydraulic servovalve. The regulator valve and the actuator can form the solenoid valve and the solenoid valve can be controlled by electric signals conveyed from an external computer, a digital circuit, an analog circuit, or a combination thereof. The propellant can be hydrogen and the regulator valve can be configured to adjust density of the hydrogen from the initial density to the regulated density by varying pressure between 100% and 200% of nominal hydrogen pressure, inclusive, to increase reactivity of the nuclear reactor core. The nominal hydrogen pressure can be 5 to 15 megapascals (MPa). Additional objects, advantages and novel features of the examples will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The objects and advantages of the present subject matter may be realized and attained by means of the methodologies, instrumentalities and combinations particularly pointed out in the appended claims. In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant teachings. However, it should be apparent to those skilled in the art that the present teachings may be practiced without such details. In other instances, well known methods, procedures, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present teachings. The various examples disclosed herein relate to passive control technologies that enable criticality control of a nuclear thermal propulsion (NTP) system with little to no active mechanical movement of circumferential control drums. By minimizing or eliminating the need for active mechanical movement of the circumferential control drums during an NTP burn, the passive control technologies simplify controlling an NTP reactor core and increase the overall performance of the NTP system. Moreover, each of the four passive control technologies are generally compatible with existing design requirements of an NTP system. A first passive control technology includes employing burnable neutron poisons, such as Gd, B-10, and Cd, in the nuclear reactor core to counter the negative reactivity insertion from the xenon (135Xe) build-up during operation. This first passive technology is referred to as Burnable-poison Operating a Reactor with Gadolinium alloy (BORGalloy). For example, a burnable poison is loaded in an outer tie tube layer of a tie tube. A second passive control technology includes tuning hydrogen pressure, for example, in the tie tube system to compensate for reactivity changes. This second passive technology is referred to as variable hydrogen density—HYPOSPRA. A third passive control technology includes extending the wait time between burn cycles (bcs) when the nuclear reactor core is shutdown or merging burn cycles. For example, in a mission to Mars, the wait time between a Trans Martian Injection 1 (TMI1) burn cycle and a Trans Martian Injection 2 (TMI2) burn cycle is varied based on fuel type to optimize reactivity. Alternatively, the TMI1 and TMI2 burn cycles can be merged by having a single TMI burn cycle. A fourth passive control technology is enhancement of temperature feedback mechanisms, such as designing the start-up and shut-down sequence to take advantage of the enhanced temperature feedback and doppler broadening of the LEU fuel in order to minimize control drum movement. For example, start up and operation can be accomplished by turning the control drums to a single predetermined angle and relying on passive temperature feedback to ensure reactor stability and the power cycle for small-scale reactivity control. This fourth passive control technology is referred to temperature feedback for simplified open-loop start-up sequences. The four disclosed passive control technologies can be used alone or in combination with one another. In combination with BORGalloy and HYPOSPRA, extending the wait time between burn cycles or merging burn cycles can solve the issues associated with control drum movement during burn. A combination of BORGalloy, HYPOSPRA, and the temperature feedback mechanism can eliminate active control drum movement, for example, from a Trans Martian Injection 1 (TMI1) burn, a Mars Orbital Injection (MOI) burn, and a Trans Earth Injection (TEI) burn; and reduce the active control drum movement needed for a Trans Martian Injection 2 (TMI2) burn. In this implementation, BORGalloy counters the effects of fissile depletion and xenon build-up during full power operation, HYPOSPRA enables the use of a single initial control drum position shared for all burns, and the enhanced temperature feedback ensures that the reactor is thermally and neutronically stable. In one-burn TMI architectures and architectures with a long wait between burn cycles, such as TMI1 and TMI2, the active control drum movement can be completely eliminated. When implemented in the NTP system, the passive control technologies provide: (1) minimal control drum movement from a set point; (2) increased performance by providing minimal loss of efficiency in the NTP system (e.g., as measured by the specific impulse); (3) ease of integration with existing NTP reactor design requirements; and (4) minimal increase in reactor mass. The specific impulse (Isp) is the total impulse (or change in momentum) delivered per unit of propellant consumed and is dimensionally equivalent to the generated thrust divided by the propellant flow rate. The propellant is any compound and can be hydrogen (molecular weight 2), helium (molecular weight 4), or water (H2O), for example. The propellant is typically stored in liquid form in a propellant tank. While the reactivity control technologies are designed for NTPs, the technologies can also be applied to terrestrial nuclear systems. More specifically, the reactivity control technologies can be applied to terrestrial nuclear systems that need to be small and compact and have to operate in remote locations for extended periods of time where increased reliability throughout the reactor's lifetime is necessary. The reactivity control technologies can also be applied to space nuclear systems for power production by enabling an extension of nuclear reactor core lifetime without requiring a large control system and suppressing fluctuations in reactivity. This can be advantageous in space where there is a need for large amounts of power in support of missions to planetary bodies, asteroids, or space stations, or where there is an absence of sunlight or other energy sources to supply energy. Reference now is made in detail to the examples illustrated in the accompanying drawings and discussed below. FIG. 1 illustrates an example of a nuclear thermal propulsion (NTP) system 100 that depicts an internal nuclear reactor core 110, a propellant line 120, a control drum 130, and other components of the assembly. In the example, the NTP system 100 is a type of nuclear reactor that operates on the principle of an expansion cycle which pumps a propellant, such as a hydrogen, through a propellant line 120 and the expansion cycle is driven by a turbopump assembly (TPA) 140. Pumps and turbines in the TPA 140 move the propellant through propellant piping 120 and the propellant becomes superheated in the nuclear reactor core 110 and expands to a gas. The NTP system 100 uses the nuclear reactor core 110, such as a compact fission reactor core that includes nuclear fuel, to generate many megawatts of thermal power (MWt) required to heat a propellant to high exhaust temperatures for rocket thrust. As shown, NTP system 100 includes an internal shield 160 and an external shield 150 to protect against the release of nuclear radiation from the nuclear reactor core 110, including against the release of neutron and gamma radiation to prevent excessive radiation heating and material damage. The internal shield 160 is located within the pressure vessel of NTP system 100 and the internal shield 160 includes interior propellant coolant channels to allow a propellant flow through. Internal shield 160 is positioned between the nuclear reactor core 110 and other components of the NTP system 100. External shield 150 includes two stacked discs and an outer radial portion. The two stacked discs of external shield 150 are typically surrounded by the outer radial portion which is cylindrically shaped or tapered. The internal and external shields 150 and 160 can be formed of lead and borated aluminum titanium hydride. Nuclear reactor core 110 is a nuclear fission reactor that includes an array of fuel elements and array of tie tubes adjacent the array of fuel elements. In the example, the array of fuel elements are interspersed with the array of tie tubes and each of the tie tubes is in direct or indirect or contact with at least one fuel element of the nuclear reactor core 110. The nuclear reactor core 110 provides thermal energy to drive the turbopump assembly (TPA) 140 and includes tie tubes to extract additional thermal energy to provide power to the TPA 140. A plurality of circumferential control drums 130 may surround the array of fuel elements and the array of tie tubes to change reactivity of the nuclear reactor core 110 by rotating the control drums 130. In the example, at least one neutron reflector 185 surrounds the nuclear reactor core 110 to regulate the neutron population of the nuclear reactor core 110. Multiple control drums 130 may be positioned in an area of the neutron reflector 185 to regulate the neutron population and reactor power level during operation. Operating the NTP system 100 during its various phases (startup, full thrust, and shutdown) is carried out by controlling the propellant, such as hydrogen, that is supplied via the TPA 140, to reach a desired reactor power level of the nuclear reactor core 110. Although not shown in FIG. 1, the TPA 140 is supplied with propellant from a propellant tank. The TPA 140 includes one or more turbopumps. In the example of FIG. 1, two turbopumps are shown; whereas, a single turbopump is shown in FIG. 2. A turbopump is a propellant pump with two main components: a rotodynamic pump and a driving gas turbine. The pump and turbine can be mounted on the same shaft, or sometimes geared together. The TPA 140 produces a high-pressure fluid for feeding the nuclear reactor core 110 and cooling the components of the NTP system 100. When the propellant is superheated to a gas in the nuclear reactor core 110, the propellant accelerates and is exhausted for expansion in a thrust chamber comprised of a nozzle 170 and a nozzle skirt extension 180. The thermal expansion of the propellant through the nozzle 170 and the nozzle skirt extension 180 provides thrust. Some of the superheated propellant can be used to turn a turbine of the TPA 140 to drive the pump. Of note, some of the superheated propellant may be returned, for example bleeded from the nuclear reactor core 110 via a bypass, to turn the turbine of the TPA 140 to drive the pump. Subsequently, the expansion cycle repeats. The generated thrust propels a vehicle that houses, is formed integrally with, connects, or attaches to the NTP system 100, such as a rocket, drone, unmanned air vehicle (UAV), aircraft, spacecraft, missile, etc. The vehicle can include various control nozzles for steering and other components. To minimize or even eliminate the need for movement of the control drums 130 during an expansion (i.e., burn) cycle, a burnable poison, such as Gadolinium (Gd), is dispersed in the array of fuel elements or the array of the tie tubes of the nuclear reactor core 110. The fuel elements and tie tubes are assembled together in the nuclear reactor core 110. Alternatively or additionally, the burnable poison (e.g., Gd) is dispersed elsewhere in other components inside the nuclear reactor core 110 that are separate from the array of fuel elements and the array of the tie tubes. For example, one or more wires may be added to the nuclear reactor core 110 that are formed of an alloy with a dispersed burnable poison, such as the Gd alloy described with respect to inner tie tube layer 820 and outer tie tube layer 850 of FIG. 8. The alloy wire is housed inside the nuclear reactor core 110. The amount of Gd dispersed in the alloy wire or other component of the nuclear reactor core 110 depends on the thickness of the component, enrichment of the Gd, and the fuel material. In an example, the Gd dispersed in the component of the nuclear reactor core 110 is in a quantity greater than 0 parts per million (ppm) and less than or equal to one-thousand (1,000) ppm, for example, the quantity of Gd can be: 10 ppm to 20 ppm, 10 ppm to 30 ppm, 10 ppm to 70 ppm, 10 ppm to 80 ppm, 10 ppm to 100 ppm, 10 ppm to 200 ppm, 10 ppm to 300 ppm, 20 ppm to 30 ppm, 20 ppm to 70 ppm, 20 ppm to 80 ppm, 20 ppm to 100 ppm, 20 ppm to 200 ppm, 20 ppm to 300 ppm, 30 ppm to 70 ppm, 30 ppm to 80 ppm, 30 ppm to 100 ppm, 30 ppm to 200 ppm, 30 ppm to 300 ppm, or greater than 0 ppm and less than 1,000 ppm. By having a low composition (loading) of Gd in the component, low self-shielding properties of Gd can be achieved. Also during the expansion cycle, the propellant stored in a propellant tank (element 201 in FIG. 2) is drawn through the nuclear reactor core 110 to cool the nuclear reactor core 110. A propellant density control valve system (shown in FIG. 2) adjusts the density of the propellant to maintain relatively constant reactivity across multiple burn cycles. Although not shown, the NTP system 100 can include a burn cycle (bc) controller to set, monitor, and control a time length of burn cycles, number of burn cycles, and shutdown period length between burn cycles (i.e., wait time). For example, the burn cycle controller controls a subsequent burn cycle by monitoring elapsed time after a prior burn cycle and comparing the elapsed time length against a minimum wait time threshold and initiating the subsequent burn cycle via the nuclear reactor core 110 only upon determining that the minimum wait time threshold is satisfied or exceeded. Such a burn cycle controller is operable to control burn cycles by directly or indirectly adjusting movement of the turbopump assembly 140 and the control drums 130. The burn cycle controller can control burn cycles by automatically adjusting burn cycle time length, number of burn cycles, wait times between burn cycles, or merge burn cycles in response to determining: (i) an amount of xenon build-up (i.e., accumulated xenon) in the nuclear reactor core 110 after an initial burn cycle; and (ii) depletion time necessary to reduce the xenon build-up to a sufficient level (e.g., zero or nearly zero) during a subsequent burn cycle. The determination of the xenon build-up amount and the depletion time can be made based on a calculation, such as by computer simulation or estimation, or empirical measurements. Alternatively or additionally, an operator can set the burn cycle time length, the number of burn cycles, the wait time between burn cycles, or merge the burn cycles via the burn cycle controller after determining the xenon build-up amount and the depletion time. The burn cycle controller also includes a temperature feedback mechanism. Burn cycle controller is discussed in further detail with respect to FIGS. 17-21. FIG. 2 is a flow diagram of the nuclear thermal propulsion system 100 of FIG. 1 during a burn (i.e., expansion) cycle. As explained in more detail below, the depicted NTP system 100 includes multiple propellant density control valve systems (PDCVS) 240, 250, 260 that control the density of the propellant to maintain relatively constant reactivity over multiple burn cycles. Although three PDCVSs 240, 250, 260 are shown, the implemented NTP system 100 may not include a PDCVS 240, 250, 260 at all or include one, two, or more of the illustrated PDCVSs 240, 250, 260. When a PDCVS 240, 250, 260 is not used, reactivity control can be achieved by employing passive reactivity control technologies disclosed herein, for example, gadolinium loading. During the burn cycle, the propellant (e.g., liquid hydrogen: LH2) flows from a propellant tank 201 to the turbopump assembly (TPA) 140. Although the TPA 140 is shown as a single turbopump in FIG. 2, the NTP system 100 typically includes more than one turbopump, for example, two turbopumps as shown in FIG. 1. The propellant is moved by the pump (P) of the turbopump assembly 140 and is split into two cooling flow paths in this example. The first cooling flow path 210 cools the nozzle 170, pressure vessel (element 330 in FIG. 3), neutron reflector (element 185 in FIG. 1), and control drums 130A-B. A propellant density control valve system (PDCVS) 250 can be in the first cooling flow path 210 to adjust the density of the propellant that is flowed to nozzle 170, pressure vessel (element 330 in FIG. 3), neutron reflector (element 185 in FIG. 1), and control drums 130A-B. Because of the transition of the propellant from a liquid to a gas state during the burn cycle, density is controlled by varying the hydrogen pressure in the propellant loop as per the ideal gas law (PV=nRT) where a percentage change in pressure is accompanied by a corresponding percentage change in density. The second cooling flow path 220 cools the tie tubes (elements 320A-N in FIG. 3) of the nuclear reactor core 110. PDCVS 240 can be in the second cooling flow path 220 to adjust the density of the propellant that is flowed to the tie tubes (elements 320A-N in FIG. 3) of the nuclear reactor core 110. In one example, when the propellant density is varied in the tie tubes and associated systems by varying percentages from 100% to 200% of nominal propellant density (equivalent to the same percentages from nominal propellant pressures), the reactivity of the nuclear reactor core 110 is noticeably increased. Alternatively, the TPA 140 itself can adjust the density of the propellant. The cooling flow paths 210, 220 are then merged and the propellant (e.g., heated hydrogen gas) is used to drive the turbine (T) of TPA 140 in a heating flow path 230 as depicted in FIG. 3. A PDCVS 260 can be in the heating flow path 230 to adjust the density of the propellant that is flowed to the fuel elements (310A-N in FIG. 3) of the nuclear reactor core 110. The propellant, which is now turbine exhaust (e.g., hydrogen gas—H2) is then routed back into the pressure vessel (element 330 in FIG. 3) and the internal shield 160 of nuclear reactor core 110. Next, the propellant enters propellant passages (elements 410A-N in FIGS. 4-5, 7) in fuel elements (310A-N in FIG. 3) of the nuclear reactor core 110. Consequently, the propellant absorbs thermal energy produced from the fission of the nuclear fuel and is superheated to high exhaust temperatures (e.g., 2550° to 29500 K), then expanded out a nozzle 170 and nozzle skirt extension 180 with a high area (e.g., 300:1) for thrust generation. Each PDCVS 240, 250, 260 can include a valve and an actuator. Each PDCVS 240, 250, 260 can be electronically or mechanically operated by one or more actuators that activate a valve mechanically, electronically, or using a combination thereof. The valve in each PDCVS 240, 250, 260 can be spring loaded to one position and electrically actuated to another position to adjust valve position and hence propellant density via electric signals from a computer. Mechanically activated valves can be advantageous for control of liquid propellant flows; whereas, electrically activated valves can be used for lighter loads, such as gaseous propellant flows. For example, the valve of each PDCVS 240, 250, 260 is controlled by the actuator via mechanical energy, such as hydraulic fluid pressure, pneumatic pressure, thermal energy, or magnetic energy. The actuator can be controlled by external mechanical energy or electronic circuitry, for example, the actuator can be driven by electric current control signals from a computer, microcontroller, digital or analog circuit, etc. The actuator can be a solenoid, variable displacement pump, electric motor, hydraulic cylinder, pneumatic, screw jack, ball screw, hoist, rack and pinion, wheel and axle, chain drive, servomechanism, stepper motor, piezoelectric, shape-memory, electroactive polymer, thermal bimorph, etc. In one example, the actuator is an internally piloted solenoid valve that acts directly on the valve. The valve and the actuator can collectively form a solenoid valve or a servovalve, such as an electrohydraulic servo valve. It may be advantageous for each PDCVS 240, 250, 260 to include multiple actuators, such as a solenoid driven by conveyed electric control signals that, in turn, acts on other actuators, such as a larger rack and pinion actuator, that in turns controls a pneumatically actuated valve, for example. As shown, the NTP system 100 comprises a propellant tank 110 to store the propellant, a nuclear reactor core inlet 231 directly or indirectly connected to the nuclear reactor core 110, a propellant line 120 directly or indirectly connected to the propellant tank to flow the propellant to the nuclear reactor core inlet 231, and a propellant density control valve system 240 or 260 directly or indirectly connected between the propellant line 120 and the nuclear reactor core inlet 231 to regulate density of the propellant flowing into the nuclear reactor core 110. NTP system 100 further comprises a turbopump assembly (TPA) 140 comprising at least one turbopump that includes a turbine (t) and a pump (p). The pump (p) is configured to cool the nuclear reactor core 110 during a burn cycle by flowing the propellant from the propellant tank 201 through the propellant line 120 to the propellant density control valve system 240 and then through the nuclear reactor core inlet 231. As shown, the nuclear reactor core inlet 231 includes a tie tube inlet 235 to flow the propellant to the array of tie tubes (elements 320A-N in FIG. 3) and is directly or indirectly connected to the propellant density control valve system 240 and a respective propellant supply passage (element 810 in FIG. 8) of a respective tie tube (element 320 in FIG. 8) in the array of tie tubes (elements 320A-N in FIG. 3). The pump (p) may be further configured to flow the propellant through the tie tube inlet 235, through the respective propellant supply passage (element 810 in FIG. 8) of the respective tie tube (element 320 in FIG. 8) in the array of tie tubes (elements 320A-N in FIG. 3), and then through a respective propellant return passage (element 840 in FIG. 8) of the respective tie tube (element 320 in FIG. 8). The NTP system 100 further comprises a propellant heating line 225 directly or indirectly connected to the turbine (t) and the respective propellant return passage (element 840 in FIG. 8) of the respective tie tube (element 320 in FIG. 8). As depicted, the NTP system 100 further comprises a second propellant density control valve system 260 directly or indirectly connected to the turbine (t) and the nuclear reactor core inlet 231 to regulate density of the propellant flowing back to the nuclear reactor core inlet 231. The pump (p) may be configured to flow the propellant returned by the respective propellant return passage (element 840 in FIG. 8) to the turbine (t) via the propellant heating line 225. The turbine is configured to flow the propellant back to the second propellant density control valve system 260 and the nuclear reactor core inlet 231 as shown. In the example, the nuclear reactor core inlet 231 further includes a fuel element inlet 245 to flow the propellant to the array of fuel elements (elements 310A-N in FIG. 3) and is directly or indirectly connected to the second propellant density control valve system 260 and a respective propellant passage (element 410A-N in FIGS. 4-5, 7) of a respective fuel element (element 310 in FIGS. 4-5, 7) of the array of fuel elements (elements 310A-N in FIGS. 3-4). The turbine (t) may be configured to flow the propellant to the second propellant density control valve system 260, through the fuel element inlet 245, and then through the respective propellant passage (element 410A-N in FIGS. 4-5, 7) of the respective fuel element (element 310 in FIGS. 4-5, 7) of the array of fuel elements (elements 310A-N in FIGS. 3-4). NTP system 100 may further comprise a pressure vessel (element 330 in FIG. 3) housing the nuclear reactor core 110 that is directly or indirectly connected to the propellant density control valve system 240 or 260. The pressure vessel (element 330 in FIG. 3) includes a pressure vessel inlet 255 connected to the periphery volume of the pressure vessel (element 330 in FIG. 3) that is outside of the nuclear reactor core 110. The pressure vessel (element 330 in FIG. 3) may include a pressure vessel outlet 295 to return the propellant passing through the periphery of the pressure vessel (element 330 in FIG. 3). The depicted NTP system 100 further comprises a propellant heating line 225 directly or indirectly connected to the turbine (t) and the pressure vessel outlet 295. The pump (p) may be further configured to flow the propellant to the pressure vessel inlet 255, through the periphery of the pressure vessel (element 330 in FIG. 3), and then flow the returned propellant from the pressure vessel outlet 295 to the turbine (t) via the propellant heating line 225. As shown, the NTP system 100 further comprises a nozzle 170, a plurality of control drums 130A-B, a neutron reflector (element 185 in FIG. 1), and a second propellant density control valve system 250 directly or indirectly connected between the propellant line 120 and the pressure vessel inlet 255 to regulate density of the propellant flowing into the nozzle 170, periphery of the pressure vessel (element 330 in FIG. 3), neutron reflector (element 185 in FIG. 1), and control drums 130A-B. In our example, each of the propellant density control valve systems 240, 250, 260 includes a regulator valve to adjust density of the propellant passing through the regulator valve from an initial density when entering the regulator valve to a regulated density when exiting the regulator valve. Each of the propellant density control valve systems 240, 250, 260 also includes an actuator to actuate the regulator valve by adjusting the regulated propellant density upwards during each subsequent burn cycle to maintain constant reactivity at a beginning of each of the subsequent burn cycles. The actuator can be electric, mechanical, thermal, magnetic, or a combination thereof. The propellant density control valve systems 240, 250, 260 can further include a flow control circuit to control speed of the actuator and the flow control circuit is a bleed-off circuit, meter-out circuit, or meter-in circuit. The regulator valve and the actuator of each of the propellant density control valve systems 240, 250, 260 can form a solenoid valve or an electrohydraulic servovalve. In an example, the regulator valve and the actuator form the solenoid valve and the solenoid valve is controlled by electric signals conveyed from an external computer, a digital circuit, an analog circuit, or a combination thereof. The propellant can be hydrogen and the regulator valve can be configured to regulate the density of the hydrogen by adjusting the percentages between 100% and 200% of nominal hydrogen density (equivalent to the same percentages from nominal hydrogen pressures) to increase reactivity of the nuclear reactor core 110. This density adjustment range can be inclusive or exclusive of the 100% or 200% endpoints (include 100% and 200% or exclude 100% and 200%). For example, the regulator valve is configured to adjust density of the hydrogen from an initial density to a regulated density by varying pressure between 100% and 200% of nominal hydrogen pressure, inclusive, to increase reactivity of the nuclear reactor core 110. The nominal hydrogen pressure can be 5 to 15 megapascals (MPa), and more specifically can be 8 MPa. FIG. 3 is a cross-sectional view 300 of the nuclear reactor core 110 and components, including an array of fuel elements 310A-N and an array of tie tubes 320A-N bundled together. As shown in FIG. 3, the fuel elements 310A-N and tie tubes 320A-N are typically hexagonally shaped elements. A beryllium barrel 340 surrounds the bundled collection that includes the array of fuel elements 310A-N and the array of tie tubes 320A-N of the nuclear reactor core 110. As depicted, the control drums 130 then surround the beryllium barrel 340 and reside on the perimeter or periphery of a pressure vessel 330. The pressure vessel 330 can be comprised of other components, including cylinders, piping, and storage tanks that transfer the propellant, such as hydrogen gas. The beryllium barrel 340 includes partially hexagonally shaped filler elements which surround the perimeter of the fuel elements 310A-N and tie tubes 320A-N that make up the nuclear reactor core 110. Typically the control drums 130, fuel elements 310A-N, and tie tubes 320A-N are the same length; however, it should be understood that the lengths can differ depending on the implementation. A portion of the nuclear reactor core 110 is encircled as element 305 and this nuclear reactor core portion 305 is magnified in FIG. 4. FIG. 4 is an enlarged plane view of a portion of the nuclear reactor core 110 of FIG. 3. The nuclear reactor core portion 305 depicts an array of fuel elements 310A-N interspersed with an array of tie tubes 320A-N. In the example, each fuel element 310A-N is in contact with three tie tubes 320A-N; however, it should be understood that fuel elements on the periphery of the nuclear reactor core 110 typically contact fewer tie tubes 320A-N. Six fuel elements 310A-N surround each tie tube 320A-N. The ratio of fuel elements 310A-N to tie tubes 320A-N can be adjusted. The fuel elements 310A-N and tie tubes 320A-N are hexagonally shaped elements. As shown, each tie tube 320 includes two tie tube layers 600 (inner and outer layers), a moderator sleeve 630, a graphite sleeve, and a coating 690. The coating 690 of the tie tube 320 can be formed of zirconium carbide (ZrC). Each fuel element 310 includes propellant passages 410A-N. FIG. 5 is an illustration of a fuel element 310 of the nuclear reactor core 110. The fuel element 310 is formed of a nuclear fuel, such as a uranium and graphite fuel. In the example, the fuel element 310 includes nineteen propellant passages 410A-N that are equally spaced opening or holes to allow the propellant to pass through a respective channel in the nuclear reactor core 110 and into a thrust chamber (not shown). In other words, the propellant passages 410A-N are the flow path for the propellant to pass through the fuel element 310 in the nuclear reactor core 110. Although not shown, the thrust chamber is typically positioned at the bottom of the nuclear reactor core 110. The propellant passages 410A-N in the fuel element 310 are approximately 2.54 mm in diameter. It should be understood that the number of propellant passages 410A-N in the fuel element 310 and size (e.g., diameter) can be varied. The external surfaces of the fuel element 310 and the propellant passages 410A-N have a deposited coating 520, such as ZrC. FIG. 6 is an illustration of a tie tube 320 of the nuclear reactor core 110. The tie tube 320 provides in-core cooling and structural support for the nuclear reactor core 110. As shown, tie tube 320 houses two tie tube layers 600 (inner and outer layers), a moderator sleeve 630, a graphite insulation layer 665, and a graphite sleeve 685 surrounded by a coating (element 690 in FIG. 4 and element 890 in FIG. 8). The moderator sleeve 630 is a neutron moderator mass, typically formed of a solid hydride (ZrH, YH, LiH, etc.), such as zirconium hydride (e.g., ZrH1.8), that thermalizes fast neutrons resulting from nuclear fission events. Because the quantity of thermal energy obtained by cooling the nozzle (element 170 in FIGS. 1-2) and control drum (element 130 in FIGS. 1-2) is inadequate, the nuclear reactor core 110 includes the tie tube 320 to extract additional thermal energy from the nuclear reactor core 110. A cooled propellant, such as hydrogen, passes through the center of the tie tube 320 via a propellant supply passage (element 810 in FIG. 8). The propellant is then returned via an outer annular flow path through the tie tube 320 via a propellant return passage (element 840 in FIG. 8). Hence, the tie tube 320 behaves as a dual pass heat exchanger. FIG. 7 is a cross-sectional view of the fuel element 310 of FIGS. 4 and 5. The length of the cross-section of the fuel element 310 is approximately 1.913 cm. The fuel element 310 includes a fuel matrix 730 that has a hexagonally shaped cross-section and is formed of (UC—ZrC)C composite material. Nineteen propellant passages 410A-N with an approximately 2.54 mm diameter opening are formed as channels in the fuel matrix 730 as depicted. A zirconium carbide (ZrC) coating 520 is deposited on the fuel matrix 730. A burnable poison, such as Gd can be dispersed inside the fuel matrix 730, which can be advantageous in terms of self-shielding, particularly for a graphite composite matrix based fuel type. FIG. 8 is a cross-sectional view of the tie tube 320 of FIGS. 4 and 6 that depicts inner and outer tie tube layers and other layers of the tie tube 320. At approximately 1.913 cm, the length (L) of the cross-section of the tie tube 320 is the same or similar to the fuel element 310. As shown, the tie tube 320 includes a propellant supply passage 810 to flow a propellant, an inner tie tube layer 820 surrounding the propellant supply passage 810, a moderator sleeve 830 surrounding the inner tie tube layer 820, a propellant return passage 840 surrounding the moderator sleeve 830, and an outer tie tube layer 850 surrounding the propellant return passage 840. The layers of the tie tube 320 are radially or annularly arranged, including the propellant supply passage 810, the inner tie tube layer 820, the moderator sleeve 830, the hydrogen return passage 840, and the outer tie tube layer 850, etc. In this example, the inner tie tube layer 820 has an approximately 0.521 mm outer diameter and a 1.02 mm thick radial wall. The moderator sleeve 830 has an approximately 0.533 mm inner diameter and an approximately 1.168 mm outer diameter. The outer tie tube layer 850 has an approximately 1.410 mm outer diameter and an approximately 0.54 mm thick radial wall. Hence, the respective radial wall thickness of the outer tie tube layer 850 is less than the inner tie tube layer 820. As shown, the tie tube 320 also includes an inner gap 860 (e.g., a first gap) that is an approximately 0.13 mm space between the inner tie tube layer 820 and the moderator sleeve 730. The tie tube 320 also includes a graphite insulation layer 865 surrounding the outer tie tube layer 850. The graphite insulation layer 865 is pyrolytic graphite thermal insulation (e.g., zirconium carbide) and has an approximately 1.613 mm outer diameter and an approximately 1.410 mm inner diameter. Tie tube 320 also includes a medial gap 870 that is an approximately 0.13 mm space (e.g., a second gap) between the outer tie tube layer 850 and the graphite insulation layer 865. The tie tube 320 also includes an outer gap 880 (e.g., third gap) that is an approximately 0.13 mm space surrounding the graphite insulation layer 865. The graphite insulation layer 865 is formed of zirconium carbide (ZrC), but ZrC can be replaced or supplemented with other materials besides zirconium carbide, such as titanium carbide, silicon carbide, tantalum carbide, hafnium carbide, ZrC—ZrB2 composite, or ZrC—ZrB2—SiC composite. It should be understood that the tie tube 320 can be formed with an arbitrary number of gaps, such as one gap, two gaps, or more than three gaps. Alternatively, the tie tube 320 can be formed with no gaps at all, for example, the inner gap 860, the medial gap 870, and the outer gap 800 may not be present. As shown, a graphite sleeve 885 surrounds the outer gap 880, and a coating 890 formed of zirconium carbide or niobium carbide surrounds the graphite sleeve 885. The graphite sleeve 885 has an approximately 1.626 mm inner diameter. The inner tie tube layer 820 and outer tie tube layer 850 can be formed of a variety of alloys, including austenitic nickel-chromium based superalloys known as Inconel. An alloy that forms the outer tie tube layer 820 may be supplemented with a burnable poison that includes Gadolinium (Gd) and the Gd is dispersed in the alloy that forms the outer tie tube layer 850. Alternatively or additionally, an alloy that forms the outer tie tube layer 820 is supplemented with a burnable poison that includes Gadolinium (Gd) and the Gd is dispersed in the alloy that forms the inner tie tube layer 720. The Gd dispersed in the inner or outer tie tube layer alloys can be in a quantity of greater than 0 parts per million (ppm) and less than or equal to one-thousand (1,000) ppm, for example, 20 parts per million (ppm) to 200 ppm, or 20 ppm to 30 ppm. The amount of Gd dispersed in the Gd alloy depends on the thickness of the component, the enrichment of the Gd, and the fuel material. By having a low composition of Gd in the inner or outer tie tube layer alloys, low self-shielding properties of Gd are advantageously obtained. Inconel alloys are oxidation and corrosion-resistant materials well suited for service in extreme environments subjected to high pressure and kinetic energy. When heated, Inconel forms a thick and stable passivating oxide layer protecting the surface from further attack. Different Inconels have widely varying compositions, but all are predominantly nickel, with chromium as the second element. In one example, Inconel 718 is used, which comprises nickel (50.0-55.0%), chromium (17.0-21.0%), iron (balance), molybdenum (2.8-3.3%), niobium (4.75-5.5%), cobalt (1.0%), manganese (0.35%), copper (0.2-0.8), aluminum (0.65-1.15%), titanium (0.3%), silicon (0.35%), carbon (0.08%), sulfur (0.015%), phosphorus (0.015%), and boron (0.006%) in varying percentages by mass. Other Inconels can be used, such as Inconel 600, 617, 625, 690, and X-750, which include subsets of the elements found in Inconel 718 and in different percentages by mass. The burnable poison can be dispersed in various locations or layers of the tie tube 320, including the moderator sleeve 830, the inner tie tube layer 820, and the outer tie tube layer 850. Of these locations, the outer tie tube layer 850 may be selected as the location of choice due to thinness of the outer tie tube layer 850 relative to the inner tie tube layer 820 and the moderator sleeve 830, as well as the reduced role of the outer tie tube layer 850 as a structural element when compared with the inner tie tube layer 820. The thinness of the outer tie tube layer 850 reduces the spatial self-shielding of the burnable poison and the lack of need to provide structural support reduces the worry that additions of Gd to the material reduces strength of the outer tie tube layer 850 below acceptable levels. As noted in FIG. 7 above, while the fuel matrix is promising in terms of self-shielding, particularly for the graphite composite fuel type matrix, the outer tie tube 850 of tie tube 320 can be advantageous because of the reduced cost compared to the exponential increase in development costs associated with nuclear fuel development. Also, the spacing size of the gaps 860, 870, and 880 can vary depending on the implementation of the tie tube 320. The outer tie tube layer 850 can also be formed of or supplemented with zirconium or zirconium carbide. Baseline Nuclear Fuel Cores FIG. 9 is a table of two reference cores based on two fuel types, Superb Use of Low Enriched Uranium (SULEU) 910 utilizing (U,Zr)C in a graphite composite matrix and the Space Capable Cryogenic Thermal Engine (SCCTE) 920 utilizing UO2 in a tungsten (W) ceramic and metal matrix (CERMET), that includes configuration and performance details. Although the examples disclosed herein relate to passive reactivity control systems applied to two baseline LEU-NTP cores that include SULEU 910 and SCCTE 920, it should be understood that different fuel cores can be used. Other fuel cores that can be used include coated UC2 in graphite; (U, Zr, X)C where X=Ta, W, Hf advanced tricarbide; (U, Zr)C (binary) (U, Zr, Nbc)C (ternary) carbide type fuels, UO2 in a refractory metal matrix such as Mo, Os, or Nb; or coated U-compounds in a refractory carbide matrix such as SiC, ZrC, or NbC. The first core, SULEU 910, is a graphite composite fueled core, that is a solid hydride moderated (ZrH, YH, LiH, etc.) LEU nuclear thermal propulsion concept. The second core, SCCTE 920, is a LEU CERMET fueled core, that is an LEU W—UO2, solid hydride moderated (ZrH, YH, LiH, etc.) LEU nuclear thermal propulsion concept. Although various solid hydride moderators can be used to form the moderator sleeve of the tie tubes to moderate the fuel elements of the SULEU 910 and SCCTE 920 cores, in an example, the moderator sleeve of the tie tubes includes ZrHx and more specifically ZrH1.8. Both SULEU 910 and SCCTE 920 are mass optimized systems designed for a 2030s human Mars mission with the same thrust and Isp. The SULEU 910 and SCCTE 920 cores are designed using the SPACE code (a variant of the SPOC code) and identified through a brute force optimization where thousands of core configurations are generated and then analyzed for their performance. The core configurations, core details, and performance specifications of SULEU 910 and SCCTE 920 are provided in FIG. 8. SCCTE 920 was originally presented at the 2015 Winter American Nuclear Society along with the details of the optimization method in Eades M. J, Deason W. R., Patel V. K., “SCCTE: An LEU NTP Concept with Tungsten Cermet Fuel,” Winter American Nuclear Society Meeting 2015, Washington D.C. (November 2015), the contents of which is incorporated by reference in its entirety as if fully set forth herein. The same optimization method was also used for SULEU 910 and was presented at the Nuclear and Emerging Technology for Space 2016 conference in Venneri P. F., Eades M. J. “A Point Design for a LEU Composite NTP system: Superb Use of Low Enriched Uranium (SULEU),” Nuclear and Emerging Technologies for Space 2016, Huntsville, Ala. (February, 2016), the contents of which is incorporated by reference in its entirety as if fully set forth herein. FIG. 10 is a graph illustrating reactivity over time of the two reference cores of FIG. 9. Specifically, FIG. 10 presents how reactivity changes for the SULEU 910 and SCCTE 920 reactors over a timeline of a DRA 5 style mission to Mars. These curves were produced with computational tools, including customized code and Monte Carlo reactor physics codes such as MCNP 6.1 and Serpent 2 for neutronic analysis. Four burn cycles are shown which are Trans Martian Injection 1 (TMI1), Trans Martian Injection 2 (TMI2), Mars Orbital Injection (MOI), and Trans Earth Injection (TEI). The TMI1, TMI2, MOI, and TEI are shown in FIGS. 13-18 as a first burn cycle (bc), a second burn cycle, a third burn cycle, and a fourth burn cycle, respectively. A number of phenomena can be seen in the graph of FIG. 10. During full power operation there are two factors which result in the reduction of reactivity which consequently requires the rotation of the control drums to maintain a critical reactor: fissile material depletion (235U) and fission product production (notably the powerful fission products 135Xe). The combination of these two factors, results in the noticeable reduction in reactivity during the full power burns. The most noticeable feature in FIG. 10, however, is the large negative reactivity insertion between TMI1 and TMI2 and the resulting reactivity surge during TMI2. This is caused by the fission product 135I which then decays (6.6 hour Half-life) into 135Xe (9.1 hour Half-life) causing the 135Xe to buildup and producing the large negative reactivity insertion. FIG. 11 is a graph illustrating a specific impulse (Isp) penalty associated with turning a control drum for a nuclear reactor core that utilizes the SCCTE core. FIG. 12 is a graph illustrating a specific impulse (Isp) penalty associated with turning a control drum for the SULEU core. In existing NTP designs, such as for SCCTE and SULEU cores, the reactivity changes noted in FIG. 10 are resolved by rotating the radial control drums. This, however, introduces a number of issues. First of all there is a loss of Isp associated with circumferential control drum movement from a designed nominal position of the control drums. The Isp loss stems from the need for each propellant coolant channel in an NTP reactor to be orificed to the power deposited in that channel in order to achieve the desired propellant coolant exit temperature. When the circumferential control drums rotate, the spatial power deposition changes and renders the careful channel orificing ineffective as it no longer aligns with the spatial power deposition. This then ensures that certain elements will be receiving more power than they were orificed for which then requires that the entire core power be reduced in order to prevent these elements from exceeding their maximum allowable temperatures and to maintain the desired thrust level. Beyond losing Isp, actively turning control drums during operation is very complicated. A nested closed loop control system with control drums and rocket power cycle is enormously complex. Furthermore, actively turning control drums introduces a failure mechanism to the reactor as control drums can get stuck or over insert reactivity. Burnable Poison—BORGalloy FIG. 13 is a graph of SULEU core burnup using different gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 during multiple Trans Martian Injection (TMI) burns. FIG. 14 is a graph of SCCTE core burnup using different gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 during multiple TMI burns. In order to counter the drop in reactivity found during full power operation due to fuel depletion and fission product accumulation, a burnable neutron poison is introduced into the nuclear reactor core, for example, in an active region of the nuclear reactor core. A burnable neutron poison is an isotope that has a large neutron absorption cross-section that is converted into non neutron-absorbing isotope with the absorption of a neutron. As the neutron poison is depleted, there is a resulting increase in the core reactivity. When done correctly, the amount of the neutron poison is selected or tailored to match the reactivity reduction from the fissile depletion and fission product build-up of the nuclear fuel. In an example, a BORGalloy (Burnable-poison Operating a Reactor with Gadolinium alloy) is utilized. The burnable poison selected is 157Gd, which is dispersed in minute quantities in the outer tie tube. The 157Gd poison is selected because of its extremely high absorption cross-section and its conversion to an isotope that has a comparatively much lower absorption cross-section. In contrast, 157Gd has a thermal absorption cross-section that it is between 2 and 4 orders of magnitude lower. Although 157Gd is used in the disclosed examples, it should be understood that other Gd isotopes can be used, including stable isotopes of 154Gd, 155Gd, 156Gd, 158Gd and 160Gd, and even less stable isotopes, such as 152Gd and 150Gd. It should also be understood that Gd in its natural isotopic composition or an enriched Gd isotope, such as enriched 157Gd, can be utilized. When the burnable poison is introduced into the nuclear reactor core such that it has minimal self-shielding (maximum exposure to the core's neutron flux), the burnable poison can be rapidly depleted and result in an appreciable change in reactivity. Additionally, the low self-shielding ensures that the depletion rate remains relatively constant for all burns, removing the need to replace the burnable poison at the beginning of each burn. While poison loaded materials exist in civilian nuclear power, such poison loaded materials are designed to compensate for fissile depletion only and have a much larger poison loading, enhancing self-shielding rather than reducing it. Various locations were explored including the moderator sleeve of the tie tube, the inner and outer tie tube layers of the tie tube, and the fuel matrix. Of these, the outer tie tube was selected as the location of choice. This is due to the thinness and reduced role of the outer tie tube layer as a structural element when compared with the inner tie tube layer. The thinness of a component (e.g. the outer tie tube layer) reduces the spatial self-shielding of the burnable poison and the lack of need to provide structural support reduces the worry that additions of Gd to the material will reduce its strength below acceptable levels. While the fuel matrix is promising in terms of self-shielding, particularly for a graphite composite matrix, the outer tie tube layer can be preferred in terms of compatibility with existing requirements. For example, introducing Gd into the fuel matrix of each of the fuel elements results in an exponential increase in development costs. As shown in FIGS. 13 and 14, with the identification of 157Gd as the burnable poison, it was then implemented into both baseline cores of SULEU and SCCTE to flatten the reactivity profile during full power operation. The results for various Gd loadings are presented in FIGS. 13 and 14 for SULEU and SCCTE, respectively. Through the variation of the Gd content, it is possible to achieve a near flat reactivity change during full power operation for the TMI1, MOI, and TEI for both cores. Specifically, 20 parts per million (ppm) for SULEU and 30 ppm for SCCTE of enriched Gd achieve near flat reactivity profiles for TMI1, MOI, and TEI. Multiple burn cycles are shown in both FIGS. 13 and 14. More specifically, four burn cycles are shown. The first burn cycle (bc) 1310, 1410 is referred to as the Trans Martian Injection 1 (TMI1) burn; the second burn cycle 1320, 1420 is referred to as the Trans Martian Injection 2 (TMI2) burn; the third burn cycle 1330, 1430 is referred as the Mars Orbital Injection (MOI) burn; and the fourth burn cycle 1340, 1440, is referred to herein as the Trans Earth Injection (TEI) burn. During the first burn cycle 1310, 1410 (TMI1) that spans a twenty minute period, the NTP system leaves Earth's surface and the reactor is on during which period of time the reactivity is relatively static and xenon builds up. After the initial twenty minute operation period of the first burn cycle 1310, 1410, the reactor is then shut down and the reactivity slowly decreases for a five hour period as a result of xenon decay. During this five hour reactor shutdown period, the NTP system is in an elliptical orbit around the Earth. During the second burn cycle 1320, 1420 (TMI2) that spans a fifteen minute period, the reactor is then turned back on to enter a Martian intercept orbit to slingshot out of Earth's orbit and towards the Martian intercept orbit at which point a large increase in reactivity is seen. Initially, during the second burn cycle 1320, 1420, there is very rapid depletion of the remaining xenon as a result of the remaining xenon being burned up. As a result of the xenon being burnt up during the second burn cycle 1320, 1420, the reactivity increases significantly towards the end of the second burn cycle and becomes relatively static. After the second burn cycle 1320, 1420, the reactor is powered down and remains off for a 200 day period as the NTP system approaches Mars. During a third burn cycle 1330, 1430 (MOI) after the 200 day Mars approach period, the reactor burns for five minutes to enter Martian orbit. The reactor is then powered off for a 500 day period in Martian orbit. After 500 days in Martian orbit, the reactor burns for another five minute period during a fourth burn cycle 1340, 1440 (TEI) to leave the Martian orbit and enter a Earth intercept trajectory. Subsequent burn cycles (not shown) can be used to enter a stable Earth orbit and be reused for subsequent missions. As discussed above, an effect of the use of the Gd burnable poison is an increased change in initial reactivity. This difference is due to the depletion of the poison, which while mitigated somewhat by the depletion of fissile material, can be significant. Without proper mitigation, this can result in the core requiring distinctly different start-up control drum positions that will in turn result in different performance characteristics for each burn. Despite this, the reactivity during all of the burn cycles shown in FIGS. 13 and 14 is generally well controlled and remains relatively static despite the initial accumulation of xenon. By controlling the spatial self-shielding, a linear depletion rate of the Gd neutron poison is attained that matches the production of xenon-135 (stable and meta-stable states) with other fission products and the depletion of the fissile material. The result is that a flat reactivity profile is attained without any operator input, removing the need for radial control drum movement during operation of the burn cycles. As shown in FIG. 13, towards the end of the five hour reactor shutdown period between the first burn cycle 1310 and second burn cycle 1320, SULEU reaches the lowest reactivity level when the Gd loading is 0 ppm. In contrast, a 60 ppm Gd loading has the highest reactivity towards the end of this five hour reactor shutdown period. During the second burn cycle 1320, a 0 ppm Gd loading results in the lowest reactivity towards the end of the second burn cycle 1320 while a 60 ppm Gd loading provides the highest reactivity. Although a 60 ppm Gd loading has the highest reactivity during the burn cycles 1310, 1320, 1330, and 1340 for SULEU fuel, a 20 ppm Gd loading can be optimal by offering the best compromise level to provide a relatively low reactivity of SULEU fuel during the five hour reactor shutdown period between the first burn cycle 1310 and second burn cycle 1320, yet provide a relatively high reactivity during the first, second, third, and fourth burn cycles 1310, 1320, 1330, and 1340. As shown in FIG. 14, towards the end of the five hour reactor shutdown period between the first burn cycle 1410 and the second burn cycle 1420, SCCTE reaches the lowest reactivity level when the Gd loading is 0 ppm. In contrast, a 70 ppm Gd loading has the highest reactivity towards the end of this five hour reactor shutdown period. During the second burn cycle 1420, a 0 ppm Gd loading results in the lowest reactivity towards the send of the second burn cycle 1420 while a 70 ppm Gd loading provides the highest reactivity. Although a 70 ppm Gd loading has the highest reactivity during the burn cycles 1410, 1420, 1430, and 1440 for SCCTE fuel, a 30 ppm Gd loading can be optimal by offering the best compromise level to provide a relatively low reactivity of SCCTE fuel during the five hour reactor shutdown period between the first burn cycle 1410 and the second burn cycle 1420, yet provide a relatively high reactivity during the first, second, third, and fourth burn cycles 1410, 1420, 1430, and 1440. While the effectiveness of the dispersed Gd can deteriorate over time as the Gd is slowly depleted, it has been shown in FIGS. 13-14 that the dispersed Gd is more than able to operate successfully for a manned mission to Mars using NTP. Variable Hydrogen Density—HYPOSPRA FIG. 15 is a graph of SULEU core burnup using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2. FIG. 16 is a graph of SCCTE core burnup using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2. To date, NTP reactors (HEU and LEU) have had only one method by which to control the reactivity of the reactor: the radial control drums in the reflector region. As has been previously shown, this is known to result in power peaking changes in the core which are then directly correlated with changes in the exit core temperature and the rocket performance of the system. However, as demonstrated in FIGS. 15 and 16, adjusting the hydrogen density in the tie tube elements can control the reactivity of the core. In addition, hydrogen density adjustments can be done in combination with Gd loadings. This reactivity control method effectuated by the NTP system 100 of FIGS. 1-2 works because of two parallel changes to the neutronic environment. First of all, increasing the density reduces radial and axial neutron leakage by acting both as a neutron reflector (axially) and thermalizing the neutron spectrum and reducing the average neutron path length. Second, by thermalizing the neutron spectrum, the fission cross-section of the core is increased, further bringing the average neutron spectrum out of the epithermal region and enhancing the fission to neutron absorption cross-section ratio of the core and enhancing the neutron economy. The combination of these two factors and the fact that the cores are under moderated results in a noticeable reactivity insertion when the hydrogen density is increased uniformly throughout the core and the opposite when it is reduced. When the hydrogen density is varied in the tie tubes and associated systems by varying percentages from 100% to 200% nominal hydrogen density (equivalent to the same percentages from nominal hydrogen pressures), the reactivity of the core is noticeably increased. The nominal hydrogen pressure can be 5 to 15 megapascals (MPa), and more specifically be 8 MPa. The slope of the line is referred to as the worth of the hydrogen pressure, that is the change in $ of reactivity per change in percent pressure. For the two cores, the hydrogen worth is 0.026 $/% change for SULEU and 0.007 $/% change for SCCTE. These are later reported in FIG. 21. This propellant density control system can have two unique modes of operation. First, the propellant density control system can be passive in the sense that no operator control is required. Second, the propellant density control system can, alternatively or additionally, be an active reactivity control system that requires an operator to provide input to manually adjust the hydrogen density similar to an operator providing input to manually radially rotate control drums. The propellant density control system has a valve system that can include an adjustable inlet or outlet valves to actively control hydrogen density in the tie tube, for example, the propellant density control valve system (e.g., element 240 in FIG. 2) of the NTP system 100 shown in FIGS. 1-2. The propellant density control valve system (e.g., element 240 in FIG. 2) provides constant reactivity insertion during each burn. By having a different hydrogen pressure for each burn, the reactivity loss from the depletion of fissile material and, if BORGalloy is implemented, the depletion of the burnable poison, can be compensated for at the beginning of each burn. This means that the starting position for full power operation is made to be consistent for TMI1, MOI, and TEL As a result, an open loop reactor control system as the initial startup position can be made to be consistent for all burns. This can be clearly seen in FIGS. 15 and 16 for SULEU and SCCTE respectively, where the optimized BORGalloy depletions runs have been adjusted by varying the hydrogen pressure and having a consistent initial reactivity. Multiple burn cycles are shown in both FIGS. 15 and 16. During the first burn cycle 1510, 1610 (TMI1) that spans a twenty minute period, the NTP system leaves Earth's surface and the reactor is on during which period of time the reactivity is relatively static and xenon builds up. After the initial twenty minute operation period of the first burn cycle 1510, 1610, the reactor is then shut down and the reactivity slowly decreases for a five hour period as a result of xenon decay. During this five hour reactor shutdown period, the NTP system is in an elliptical orbit around the Earth. During a second burn cycle 1520, 1620 (TMI2) that spans a fifteen minute period, the reactor is then turned back on to enter a Martian intercept orbit to slingshot out of Earth's orbit and towards the Martian intercept orbit at which point a large increase in reactivity is seen. Initially, during the second burn cycle 1520, 1620, there is very rapid depletion of the remaining xenon as a result of the remaining xenon being burned up. As a result of the xenon being burnt up during the second burn cycle, 1520, 1620 the reactivity increases significantly towards the end of the second burn cycle 1520, 1620 and becomes relatively static. After the second burn cycle 1520, 1620, the reactor is powered down and remains off for a 200 day period as the NTP system approaches Mars. During a third burn cycle 1530, 1630 (MOI) after the 200 day Mars approach period, the reactor burns for five minutes to enter Martian orbit and land on Mars. As shown, the reactivity is relatively static during the third burn cycle 1530, 1630. The reactor is then powered off for a 500 day period on the surface of Mars. After 500 days on the surface of Mars, the reactor burns for another five minute period during a fourth burn cycle 1540, 1640 (TEI) to leave the Martian surface and enter Martian elliptical orbit. Subsequent burn cycles (not shown) are used to enter into an Earth intercept trajectory, enter Earth orbit, and land back on Earth. In FIG. 15, the reactivity profile of SULEU during four burn cycles is plotted using SULEU without any Gd loadings and hydrogen pressure correction (default SULEU). Also plotted is the reactivity profile of SULEU with a Gd loading of 20 ppm (SULEU & BORGalloy). Finally, the reactivity profile of SULEU with a combination of a Gd loading of 20 ppm and hydrogen pressure correction is plotted (SULEU, BORGalloy & Press. Correct.). As shown, the reactivity of SULEU is well controlled and optimal when using the combination of Gd loading and hydrogen pressure correction. In FIG. 16, the reactivity profile of SCCTE during four burn cycles is plotted using SCCTE without any Gd loadings and hydrogen pressure correction (default SCCTE). Also plotted is the reactivity profile of SCCTE with a Gd loading of 30 ppm (SULEU & BORGalloy). Finally, the reactivity profile of SCCTE with a combination of a Gd loading of 30 ppm and hydrogen pressure correction is plotted (SCCTE, BORGalloy & Press. Correct.). As shown, the reactivity of SCCTE is well controlled and optimal when using the combination of Gd loading and hydrogen pressure correction. Varying the hydrogen density compensates for the change in reactivity of the nuclear reactor core due to the depletion of fissile material and poisons in the nuclear reactor core without perturbing the radial power profile of the nuclear reactor core. In the example, the hydrogen propellant is introduced into the tie tubes of the nuclear reactor core at different pressures and an empirical measurement of the hydrogen density in the tie tube elements of the nuclear reactor core is made. The nominal hydrogen density is determined to range from 5 to 15 megapascals (MPa), and more specifically 8 MPa. By increasing the hydrogen density, the reactivity is increased and by reducing the hydrogen density the reactivity is decreased. Applying this uniformly to the nuclear reactor core allows for reactivity insertion and removals without changing the power profile of the nuclear reactor core. By adjusting the pressure in the tie tubes of the nuclear reactor core and maintaining a constant pressure during the burn, a constant reactivity insertion that is able to accurately compensate for any change in initial reactivity between burns is achieved. Accordingly, the moderating capabilities of hydrogen results in a corresponding change in reactivity of the nuclear reactor core when the hydrogen concentration in the nuclear reactor core is changed without affecting radial power distribution of the nuclear reactor core. When combined with other reactivity controls, such as burnable poisons in the nuclear reactor core, the control drum movement can be minimized to the point where control drums are used only for start-up and shut-down and consistently return to the same position. The power cycle of the nuclear reactor core is adapted to allow for variable tie tube hydrogen pressure. Adjusting Wait Time Between Burn Cycles or Merging Burn Cycles FIG. 17 is a graph of minimum wait time between periods of full-power operation for the SULEU core using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2. FIG. 18 is a graph of minimum wait time between periods of full-power operation for the SCCTE core using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2. One method to reduce the effect of xenon on the core reactivity is to increase the wait time between burns or eliminate the second burn. Four burn cycles are shown in both FIGS. 17 and 18 beginning with the TMI1 burn (first burn cycle 1710, 1810). The effect of this can already be seen in the lack of impact the build-up of xenon has on the Mars Orbital Injection (MOI) burn (third burn cycle 1730, 1830) and Trans Earth Injection (TEI) burn (fourth burn cycle 1740, 1840), both of which occur months after the previous burn. In particular, MOI occurs 200 days after the TMI2 burn (second burn cycle 1720, 1820) and TEI occurs 500 days after MOI. In both of these cases, MOI in the third burn cycle 1730, 1830 and TEI in the fourth burn cycle 1740, 1840, ample time is allowed for the xenon to fully decay away and be absent from the core at start-up. In the current mission profile, however, the TMI2 burn (elements 1320, 1420 in FIGS. 13-14) occurs 5 hours after TMI1 (elements 1310, 1410 in FIGS. 13-14), placing it near the point of highest accumulation of 135Xe. Consequently, the core has two major issues that need to be resolved. First, it requires a significant positive reactivity insertion in order to be made critical (˜$8 for SULEU due to its thermal spectrum and ˜$2 for SCCTE). Second, during TMI2 burn (elements 1320, 1420 in FIGS. 13-14) the core undergoes a non-negligible reactivity transient as the xenon is depleted. This transient is an increase in the core reactivity whose rate of increase is directly proportional to the reactor power. Needless to say, this is significantly faster than any desired transient. To resolve this, it is possible to extend the wait between the two burns as shown in FIGS. 17-18. Ideally, the wait time would be greater than 3 days, the time needed for the xenon to be almost completely decayed away. However, due to the need to minimize time in orbit around the Earth for manned missions (Van Allen radiation belts), the time between the two burns, that is the first burn cycle 1710, 1810 for TMI1 and the second burn cycle 1720, 1820 for TMI2 needs to be minimized. In FIGS. 17 and 18, the minimum wait times between the two burns to achieve a reasonable initial reactivity insertion for start-up and a controllable reactivity transient during operation are identified. For SULEU fuel, this optimized minimum wait time is a 72 hour time period between the first burn cycle 1710 for TMI1 and the second burn cycle 1720 for TMI2. For SCCTE fuel, the optimized minimum wait time is a 48 hour time period between the first burn cycle 1810 for TMI1 and the second burn cycle 1820 for TMI2. The results of an increased wait from 5 hours to 72 hours between TMI1 and TMI2 is shown in FIG. 17 for SULEU fuel. And FIG. 18 depicts the results of an increased wait from 5 hours to 48 hours between TMI1 and TMI2 for SCCTE fuel. When compared with FIGS. 15-16, it can be seen that the results are vastly improved using the optimized minimum wait time. The best result in terms of maintaining constant reactivity over subsequent burn cycles and a high sustained reactivity compromise level during burn cycles is attained using a combination of hydrogen pressure correction control, gadolinium (Gd) loading, and minimum wait time features of the NTP system 100 of FIGS. 1-2. When just the combination of Gd loading and minimum wait time are used, the highest reactivity is achieved. Just varying the wait time alone resulted in relatively constant reactivity over subsequent burn cycles. Control of the minimum wait time between burns is effectuated by the NTP system 100 of FIGS. 1-2 and the NTP system 100 includes a burn cycle controller, such as a computer that includes reactor control software, a digital or analog circuit, a mechanical timer switch, or a combination thereof. For example, the burn cycle controller can be implemented via a digital or analog circuit or software programming instructions stored in a memory that are executed by a processor of the computer that regulate or monitor an adjustable timer circuit or programming instructions and the adjustable timer circuit or programming instructions allow the minimum wait time between burns to be set to a minimum wait time between burns. In response to determining that the minimum wait time between burns has elapsed, the burn cycle controller of the NTP system 100 enables the various components of the NTP system 100 of FIGS. 1-2 to carry out the next burn (i.e., expansion) cycle. If the minimum wait time between burns has not elapsed, the burn cycle controller of the NTP system 100 does not allow the various components of the NTP system 100 of FIGS. 1-2 to carry out the next burn (i.e., expansion) cycle. The burn cycle controller can be overridden by an operator for safety reasons, for example. FIG. 19 is a graph of minimum wait time between periods of full-power operation for the SULEU core using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2 in a single Trans Martian Injection (TMI) burn. FIG. 20 is a graph of minimum wait time between periods of full-power operation for the SCCTE core using optimized gadolinium loadings dispersed in an alloy that forms the outer tie tube layer of the tie tube of FIG. 8 and hydrogen pressure correction control by the NTP system 100 of FIGS. 1-2 in a single TMI burn. Both FIGS. 19-20 show another approach to resolve the issue of buildup of xenon between TMI1 and TMI2. In the graphs of FIGS. 19-20, the NTP system 100 of FIGS. 1-2, including the burn cycle controller, has adjusted the mission profile control to have a single TMI burn that occurs during the first burn cycle 1910, 2010; MOI during the second burn cycle 1920, 2020; and TEI during the third burn cycle 1930, 2030. The approach shown is to do a one burn TMI in the first burn cycle 1910, 2010 much like how the TEI is one burn in the third burn cycle 1930, 2030 of FIG. 19-20. However, the length of the single burn cycle for the combined TMI in the first burn cycle 1910, 2010, is longer than the two separate burn cycles that were used previously in the separate TMI1 and TMI2 burns. A one burn TMI 1910, 2010 has a greater gravity loss term than a 2 burn TMI, but it can be seen in FIGS. 19-20 that a one burn TMI significantly reduces the effects of xenon build up. The result of a one burn TMI1 and TMI2 are shown in FIGS. 19 and 20 for SULEU and SCCTE as elements 1910, 2010, respectively. When compared with FIGS. 15-16, it can be seen that the results are vastly improved using a merged TMI burn cycle (TMI1 and TMI2). As shown, the best result in terms of holding constant reactivity over subsequent burn cycles and a high sustained reactivity compromise level during burn cycles is achieved using a combination of hydrogen pressure correction control, gadolinium (Gd) loading, and the merged TMI burn features of the NTP system 100 of FIGS. 1-2, including the burn cycle controller. When the combination of Gd loading and merged TMI burn cycle are used, the highest reactivity is achieved. Just merging the TMI burn cycle resulted in somewhat constant reactivity over subsequent burn cycles, but not as well as the combination with hydrogen pressure correction control and gadolinium (Gd) loading. Control of the number and length of burns, for example, of the first burn cycle 1910, 2010 is effectuated by the NTP system 100 of FIGS. 1-2. As noted above, the NTP system 100 of FIGS. 1-2 includes a burn cycle controller, such as a computer that includes reactor control software, a digital or analog circuit, a mechanical timer switch, or a combination thereof. For example, the burn cycle controller allows a mission profile to be set by adjusting the number of burn cycles, a respective length of each of the burn cycles, and a respective shutdown period between each of the burn cycles. The burn cycle controller can be implemented via a digital or analog circuit or software programming instructions stored in a memory that are executed by a processor of the computer that are operable to set a cycle length timer to the length of each burn cycle, set a counter to the number of burn cycles, and set one or multiple shutdown timers to the shutdown period between a number of respective burn cycles. The burn cycle controller regulates and monitors the number, length of burn cycles, and the shutdown periods that have been set. If the respective burn cycle has not elapsed, the burn cycle controller of the NTP system 100 continues to carry out the respective burn cycle. In response to determining that the respective burn cycle has elapsed, the burn cycle controller of the NTP system 100 disables the various components of the NTP system 100 of FIGS. 1-2. The subsequent burn cycle is carried out after the shutdown period that was previously set between the prior burn cycle and the next burn cycle in the mission profile elapses. Of note, if the minimum wait time between burns has not elapsed as previously described, the burn cycle controller of the NTP system 100 does not allow the various components of the NTP system 100 of FIGS. 1-2 to carry out the next burn (i.e., expansion) cycle. As noted previously, the burn cycle controller can be overridden by an operator for safety reasons, for example. Temperature Feedback for Simplified Start-Up Procedure One of the objectives of a passively controlled NTP is to have an open-loop start up sequence. The ultimate goal is to have the operator turn the control drums to a predetermined position, and that the reactor will naturally increase in temperature until it stabilizes at a well-defined temperature without further operator input. An element of closed loop control will still be present as the power is then increased by increasing the propellant coolant flow rate through the core and will require appropriate valving of the rocket as is the case with most modern rocket engines. Hence, the core can have a series of built-in negative reactivity coefficients that as reactor power and temperature increase, the excess reactivity of the core will decrease to the point where a stable temperature is reached. FIG. 21 is a table of reactivity coefficients for SULEU and SCCTE cores. In the presented reference SULEU and SCCTE cores, with an examination of the fuel and moderator temperature reactivity coefficients, such a start-up sequence can be achieved. The principal reactivity feedback mechanisms for SULEU and SCCTE are reported in FIG. 21. The enhanced thermal feedback coefficients stem from the fact that LEU-NTP systems have an enhanced fuel temperature feedback from the large fraction of 238U in the fuel. With the increase in temperature, the 238U undergoes spectrum Doppler broadening and enhances its neutron absorption, resulting in negative reactivity insertion. With this in mind, a moderated LEU-NTP system can be designed with inherent negative feedback to ensure stability at the desired operating temperature. The burn cycle controller discussed above can be operable to directly or indirectly monitor current operating temperature of the nuclear reactor core 110 of the NTP system 100 FIGS. 1-2 to provide temperature feedback, and then adjust the nuclear reactor core 110 during the start-up sequence. However, the large hydrogen worth of moderated NTP systems can result in unstable systems. While the significant negative reactivity feedback of the fuel helps to significantly mitigate the issue, it does not single handedly resolve the issue. In order to ensure the viability of an open loop start-up sequence, the NTP system can be designed such that the hydrogen density in the tie tubes is sufficiently decoupled from the core power, for example, using the NTP system 100 of FIGS. 1-2. This ensures that the dominant temperature feedback mechanisms for the core are the negative fuel and moderator temperature feedback. It will be understood that the terms and expressions used herein have the ordinary meaning as is accorded to such terms and expressions with respect to their corresponding respective areas of inquiry and study except where specific meanings have otherwise been set forth herein. Relational terms such as first and second and the like may be used solely to distinguish one entity or action from another without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” “includes,” “including,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises or includes a list of elements or steps does not include only those elements or steps but may include other elements or steps not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “a” or “an” does not, without further constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. Unless otherwise stated, any and all measurements, values, ratings, positions, magnitudes, sizes, and other specifications that are set forth in this specification, including in the claims that follow, are approximate, not exact. Such amounts are intended to have a reasonable range that is consistent with the functions to which they relate and with what is customary in the art to which they pertain. For example, unless expressly stated otherwise, a parameter value or the like may vary by as much as ±10% from the stated amount. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various examples for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, the subject matter to be protected lies in less than all features of any single disclosed example. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter. While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present concepts.
050826204	abstract	A recirculation system for a boiling water reactor includes a plurality of circumferentially spaced impeller-driven reactor internal pumps disposed in a downcomer for pumping a first portion of reactor coolant, and a plurality of circumferentially spaced fluid-driven jet pumps disposed in the downcomer for pumping a remaining portion of the coolant in the downcomer. In an exemplary embodiment, the jet pumps are driven by a portion of feedwater provided to the reactor.
	abstract	A single-element ultrasonic sensor includes a single transducer element and transmits an ultrasonic wave on the basis of a pulse wave. An ultrasonic array sensor includes a plurality of transducer elements and receives an ultrasonic reflected wave. A pulsar supplies the pulse wave to the single element ultrasonic sensor. A receiver receives electric signals from the transducer elements included in the ultrasonic array sensor. An amplification and conversion unit amplifies the electric signals received from the transducer elements included in the ultrasonic array sensor, converts the electric signals into digital signals, and arranges the digital signals in a serial order so as to generate a serial digital signal. An image generator generates an image on the basis of the serial digital signal.
	claims	1. A method for treating a tumor of a patient with positively charged particles in a treatment room, comprising the steps of:providing an initial radiation treatment plan;a main controller implementing the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from a synchrotron, along a beam transport line, through a nozzle system proximate the treatment room, and into the tumor;concurrent with said step of implementing, imaging the tumor to generate a current image, said step of imaging further comprising the step of:generating a positron emission tomogram of the tumor while the positively charged particles are being delivered to the patient;upon detection of movement of the tumor relative to surrounding constituents of the patient using the current image, said main controller automatically generating an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan; andrepeating said steps of implementing, imaging, and generating an updated treatment plan at least n times, where n is a positive integer of at least one. 2. The method of claim 1, said step of imaging further comprising the step of:calculating a beam path of an individual proton, of the positively charged particles, using output of a first detector sheet positioned between the patient and a scintillation detector positioned on an opposite side of the patient relative to an entry point of the individual proton into the patient. 3. The method of claim 1, further comprising the step of:an unsupervised computer implemented algorithm automatically providing at least changes in the updated treatment plan relative to a prior version of the current radiation treatment plan and proceeding with said step of repeating. 4. The method of claim 1, further comprising the step of:said unsupervised computer implemented algorithm automatically proceeding with said step of repeating without an explicit real-time provided approval input to continue. 5. A method for treating a tumor of a patient with positively charged particles in a treatment room, comprising the steps of:providing an initial radiation treatment plan;a main controller implementing the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from a synchrotron, along a beam transport line, through a nozzle system proximate the treatment room, and into the tumor;concurrent with said step of implementing, imaging the tumor to generate a current image;upon detection of movement of the tumor relative to surrounding constituents of the patient using the current image, said main controller automatically generating an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan, said step of automatically generating an updated treatment plan further comprising the step of:an unsupervised computer implemented algorithm using a set of computer coded inputs to automatically generate the updated treatment plan the updated treatment plan requiring an unplanned for, in the original radiation treatment plan, movement of said nozzle system; andrepeating said steps of implementing, imaging, and generating an updated treatment plan at least n times, where n is a positive integer of at least one. 6. The method of claim 5, further comprising the step of:a coded algorithm automatically generating the original radiation treatment plan using inputs comprising all of:a set of images of the tumor;dose distribution parameters;patient motion parameters; anda known geometry of a dynamically movable treatment room object. 7. The method of claim 6, further comprising the steps of:using output from a fiducial marker system, comprising a fiducial marker and a fiducial detector, in said step of automatically generating the updated radiation treatment plan, said output generated using detected photons, the photons passing from said fiducial marker to said fiducial detector; andautomatically increasing energy of particles extracted from said synchrotron to yield a radiation treatment plan energy of the positively charged particles after loss of energy passing through the movable treatment room object. 8. A method for treating a tumor of a patient with positively charged particles in a treatment room, comprising the steps of:providing an initial radiation treatment plan;a main controller implementing the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from a synchrotron, along a beam transport line, through a nozzle system proximate the treatment room, and into the tumor;concurrent with said step of implementing, imaging the tumor to generate a current image;upon detection of movement of the tumor relative to surrounding constituents of the patient using the current image, said main controller automatically generating an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan; andrepeating said steps of implementing, imaging, and generating an updated treatment plan at least n times, where n is a positive integer of at least one,the updated treatment plan directing an originally unplanned for, in the original radiation treatment plan, movement of said nozzle system. 9. The method of claim 8, further comprising the step of:the updated treatment plan directing a disconnect of said nozzle system from said beam transport line and a connection of said nozzle system to a second beam transport line. 10. A method for treating a tumor of a patient with positively charged particles in a treatment room, comprising the steps of:providing an initial radiation treatment plan;a main controller implementing the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from a synchrotron, along a beam transport line, through a nozzle system proximate the treatment room, and into the tumor;concurrent with said step of implementing, imaging the tumor to generate a current image;upon detection of movement of the tumor relative to surrounding constituents of the patient using the current image, said main controller automatically generating an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan; andrepeating said steps of implementing, imaging, and generating an updated treatment plan at least n times, where n is a positive integer of at least one,the updated treatment plan directing rotational movement of a gantry about the patient, said gantry comprising a counterweight counter balance comprising a first moment of force within ten percent of a second moment of force of elements of said gantry on an opposite side of an axis of rotation of said gantry. 11. An apparatus for treating a tumor of a patient with positively charged particles in a treatment room, comprising:a synchrotron connected to a nozzle system, proximate the treatment room, by a beam transport line;a main controller provided an initial radiation treatment plan, said main controller configured to implement the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from said synchrotron, along said beam transport line, through said nozzle system and into the tumor;an imaging system configured to, concurrent with implementation of the current radiation treatment plan by said main controller, image the tumor to generate a current image, said imaging system further comprising:a positron emission tomography system, rotatable about the patient, comprising a source and a detector continually out of a path of the positively charged particles;said main controller configured to, upon detection of movement of the tumor relative to adjacent constituents of the patient using the current image, automatically generate an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan; andsaid main controller configured to repeat the implementation of the current radiation treatment plan, use the current image, and generate an updated treatment plan at least n times, where n is a positive integer of at least one. 12. The apparatus of claim 11, said imaging system further comprising:a first sheet, positioned between said nozzle system and the patient, configured to emit first photons upon a proton, of the positively charged particles, traversing said first sheet;a second sheet, positioned between said first sheet and the patient, configured to emit second photons upon the proton traversing said second sheet; anda scintillation detector system positioned on an opposite side of the patient from the nozzle system configured to detect the proton. 13. The apparatus of claim 12, said imaging system further comprising:an X-ray system configured to co-rotate and co-translate with said positron emission tomography system. 14. The apparatus of claim 12, further comprising:a gantry configured to rotate about an axis of rotation, said gantry comprising a counterweight counter balance, on a first side of the axis of rotation, comprising a first moment of force within ten percent of a second moment of force of elements of said gantry on an opposite side of the axis of rotation. 15. An apparatus for treating a tumor of a patient with positively charged particles in a treatment room, comprising:a synchrotron connected to a nozzle system, proximate the treatment room, by a beam transport line;a main controller provided an initial radiation treatment plan, said main controller configured to implement the initial radiation treatment plan, as a current radiation treatment plan, using the positively charged particles delivered from said synchrotron, along said beam transport line, through said nozzle system and into the tumor;a gantry configured to rotate about an axis of rotation passing within one meter of the patient during use, said gantry comprising:all movable counterweight elements, on a first side of the axis of rotation comprising a first combined moment of force; andall movable gantry elements, on a second side of the axis of rotation opposite the first side of the axis of rotation, comprising a second moment of force within ten percent of the first moment of force; andan imaging system configured to, concurrent with implementation of the current radiation treatment plan by said main controller, image the tumor to generate a current image;said main controller configured to, upon detection of movement of the tumor relative to adjacent constituents of the patient using the current image, automatically generate an updated treatment plan, the updated treatment plan becoming the current radiation treatment plan; andsaid main controller configured to repeat the implementation of the current radiation treatment plan, use the current image, and generate an updated treatment plan at least n times, where n is a positive integer of at least one.
	claims	1. A core spray sparger T-box clamp for a sparger T-box in a shroud of a nuclear reactor pressure vessel, the sparger T-box clamp comprising:an anchor plate configured to be substantially aligned with a closed end of the T-box;a carrier plate slidably secured to an upper section of the anchor plate and configured to be latched to an upper side of the T-box, wherein the carrier plate extends horizontally from the anchor plate and the carrier plate includes a fastener extending downwardly and configured to be latched to the upper side of the T-box;a saddle bracket engaged with a lower section of the anchor plate and configured to be slidably engaged with a lower side of the T-box, wherein the saddle bracket extends horizontally from the anchor plate and the saddle bracket includes a fastener extending upwardly and configured to be latched to the lower side of the T-box and the saddle bracket is separated from the carrier plate by a distance greater than a distance between the upper side and the lower side of the T-box, anda pair of clamp blocks on opposite sides of the anchor plate, slidably secured to the anchor plate and each block configured to be fixed to a respective sparger pipe coupled to the T-box. 2. A core spray sparger T-box clamp as in claim 1 wherein the fastener of the carrier plate includes a first locating pin configured to extend into the upper side of the T-box and the fastener of the saddle bracket includes a second locating pin configured to extend into the lower side of the T-box, wherein the first pin is parallel to the second pin. 3. A core spray sparger T-box clamp as in claim 2 wherein the first locating pin and the second locating pin are vertical. 4. A core spray sparger T-box clamp as in claim 1 wherein the carrier plate further comprises a tongue adapted to slide into a slot in the anchor plate. 5. A core spray sparger T-box clamp as in claim 4 wherein the tongue is parallel to the fastener of the carrier plate. 6. A core spray sparger T-box clamp as in claim 1 wherein the carrier plate includes a horizontal arm having an arched lower surface conforming to an upper portion of a cylindrical sidewall of the T-box, wherein the cylindrical sidewall includes the upper side and the lower side of the T-box. 7. A core spray sparger T-box clamp as in claim 1 wherein the saddle bracket includes a horizontal plate having an arched upper surface conforming to a lower portion of a cylindrical sidewall of the T-box, wherein the cylindrical sidewall includes the upper side and the lower side of the T-box. 8. A core spray sparger T-box clamp as in claim 1 further comprising a bearing plate extendable from the anchor plate and configured to be biased against a cover plate of the T-box. 9. A core spray sparger T-box clamp as in claim 8 further comprising bearing bolts connecting the anchor plate to the bearing plate. 10. A core spray sparger T-box clamp as in claim 7 wherein the saddle bracket includes at least one cap screw extending through the bracket and into a threaded aperture in the anchor plate. 11. A core spray sparger T-box clamp for a sparger T-box in a shroud of a nuclear reactor pressure vessel, the sparger T-box clamp comprising:an anchor plate configured to substantially align with a cover plate welded to an end of the T-box;a bearing plate extendable horizontally from the anchor plate and configured to abut the end of the T-box;a carrier plate slidably secured to an upper side of the anchor plate and configured to be latched to an upper region of a sidewall of the T-box, wherein the carrier plate extends horizontally from the anchor plate and wherein the carrier plate includes a latch extending towards the upper region and configured to latch to the upper region of the sidewall, anda saddle bracket attached to a lower side of the anchor plate, and said saddle bracket is configured to be latched to a lower region of the sidewall of the T-box, wherein the saddle bracket is parallel to the carrier plate and is separated from the carrier plate by a distance greater than a distance between the upper region and the lower region of the sidewall, and wherein the saddle bracket includes a latch extending towards the lower region and configured to latch to the lower region of the sidewall. 12. A core spray sparger T-box clamp as in claim 11 wherein the latch of the carrier plate is a first locating pin configured to extend into the upper region of the sidewall of the T-box and the latch of the saddle bracket is a second locating pin configured to extend into the lower region of the sidewall, wherein the first locating pin is parallel to the second locating pin. 13. A core spray sparger T-box clamp as in claim 11 wherein the saddle bracket includes an arc shaped surface conforming to a lower sidewall surface of the T-box. 14. A core spray sparger T-box clamp as in claim 1 further comprising a bearing plate bolt coupled to the bearing plate and extending through a threaded aperture in the anchor plate.
	summary
	claims	1. An SAXS (Small Angle X-ray Scattering) system for x-ray scattering analysis of a sample, the SAXS system comprising:an x-ray source for generating a beam of x-rays propagating along a transmission axis in a beam transmission direction;a beam forming element disposed downstream of said x-ray source, said beam forming element structured and positioned to collect x-rays emitted from said x-ray source and to generate a beam of defined divergence and monochromatism;a first hybrid slit disposed downstream of said beam forming element, said first hybrid slit having a first aperture; anda second hybrid slit disposed downstream of and spaced apart from said first hybrid slit, said second hybrid slit having a second aperture, wherein at least one of said first and said second hybrid slits defines a shape of a cross section of said beam incident on the sample by means of at least three hybrid slit elements, each hybrid slit element comprising a single crystal substrate bonded to a base with a taper angle α≠0, wherein said single crystal substrates of said hybrid slit elements limit said first or second aperture, said hybrid slit elements being staggered with an offset along said transmission axis, wherein each hybrid slit element is adjustable in said beam transmission direction; andan x-ray detector for detecting x-rays originating from the sample, wherein each of said at least three hybrid elements defining the shape of the cross section of said beam incident on the sample is disposed, structured and dimensioned to satisfy the following relationship: Δd=OS tan(2θ), with Δd being a difference between distances to said transmission axis of said beam of neighboring single crystal substrates, 2θ a divergence half-angle of said beam and OS an offset distance between neighboring single crystal substrates in said beam transmission direction, said x-ray source, said beam forming element, said first hybrid slit, said second hybrid slit and said x-ray detector thereby being disposed, structured and dimensioned in order to increase signal to noise ratio in SAXS measurements on the sample. 2. The SAXS system of claim 1, wherein said hybrid slit elements are arranged to form a polygon with n edges viewed in projection along said transmission axis, with n>4. 3. The SAXS system of claim 2, wherein said hybrid slit elements are arranged to form a polygon with n edges viewed in projection along said transmission axis, with n≥8. 4. The SAXS system of claim 2, wherein said shape of said cross section of said beam defined by said first or said second apertures is a regular polygon. 5. The SAXS system of claim 1, wherein said hybrid slit elements are movable perpendicular to said transmission axis. 6. The SAXS system of claim 5, wherein said hybrid slit elements are movable in a radial direction. 7. The SAXS system of claim 1, wherein opposing hybrid slit elements form a pair and said hybrid slit elements are staggered pairwise. 8. The SAXS system of claim 1, further comprising a beamstop which is positioned between said hybrid slit and said detector for blocking incident x-rays. 9. The SAXS system of claim 8, wherein a radial position and a position along said transmission axis of said hybrid slit elements are chosen to optimize a flux of detected, scattered x-rays. 10. The SAXS system of claim 1, wherein said x-ray source is a laboratory source. 11. The SAXS system of claim 1, wherein said taper angle α is larger than a beam divergence 2θ. 12. The SAXS system of claim 11, wherein said taper angle α>10°.
	claims	1. A ray beam guiding device for guiding ray beams in a ray inspection apparatus, the ray beam guiding device being provided in a housing of the ray inspection apparatus, two ends of the ray beam guiding device being connected to a front collimator and a rear collimator, respectively, the ray beam guiding device comprising a plurality of guiding walls and a guiding cavity surrounded by the guiding walls,wherein the guiding walls are formed of a first material which is capable of absorbing rays or the first material is coated on an inside of the guiding walls, and the guiding cavity has a central axis extending in a direction from the rear collimator to the front collimator, andwherein the ray beam guiding device further comprises at least one fin plate provided in the guiding cavity of the ray beam guiding device, the at least one fin plate being configured for blocking and/or absorbing scattered rays. 2. The ray beam guiding device according to claim 1, wherein the ray beam guiding device comprises a rear fin portion provided on an end of the rear collimator located in the guiding cavity, the rear fin portion comprising at least one fin plate. 3. The ray beam guiding device according to claim 1, wherein the ray beam guiding device comprises a front fin portion provided on an end of the front collimator located in the guiding cavity, the front fin portion comprising at least one fin plate. 4. The ray beam guiding device according to claim 1, wherein the fin plate is sized such that most of the scattered rays through the front collimator and/or the rear collimator are blocked by the fin plate. 5. The ray beam guiding device according to claim 1, wherein the fin plate is formed of a second material which is capable of absorbing rays or the second material is coated on a side of the fin plate facing towards the central axis of the guiding cavity, for absorbing the scattered rays through the front collimator and/or the rear collimator. 6. The ray beam guiding device according to claim 1, wherein each fin plate comprises a first portion connected to the front collimator and/or the rear collimator and a second portion extending parallel to the central axis of the guiding cavity. 7. The ray beam guiding device according to claim 2, wherein the rear fin portion comprises a first fin plate and a second fin plate, and the first fin plate and the second fin plate are symmetrical with respect to the central axis of the guiding cavity. 8. The ray beam guiding device according to claim 2, wherein the rear fin portion consists of one fin plate located at one side of the central axis of the guiding cavity. 9. The ray beam guiding device according to claim 5, wherein the first material and the second material are the same material. 10. A ray inspection apparatus, comprising:a ray source configured to generate rays;a rear collimator configured to process the rays generated by the ray source into a ray beam with a specific shape;a front collimator configured to divide the ray beam penetrating an object to be inspected into a plurality of ray beams;a detector;a ray beam guiding device according to claim 1;wherein the ray beam guiding device is arranged between the front collimator and the rear collimator. 11. The ray beam guiding device according to claim 2, wherein the ray beam guiding device comprises a front fin portion provided on an end of the front collimator located in the guiding cavity, the front fin portion comprising at least one fin plate. 12. The ray beam guiding device according to claim 2, wherein the fin plate is sized such that most of the scattered rays through the front collimator and/or the rear collimator are blocked by the fin plate. 13. The ray beam guiding device according to claim 3, wherein the fin plate is sized such that most of the scattered rays through the front collimator and/or the rear collimator are blocked by the fin plate. 14. The ray beam guiding device according to claim 2, wherein each fin plate comprises a first portion connected to the front collimator and/or the rear collimator and a second portion extending parallel to the central axis of the guiding cavity. 15. The ray beam guiding device according to claim 3, wherein each fin plate comprises a first portion connected to the front collimator and/or the rear collimator and a second portion extending parallel to the central axis of the guiding cavity. 16. The ray beam guiding device according to claim 4, wherein each fin plate comprises a first portion connected to the front collimator and/or the rear collimator and a second portion extending parallel to the central axis of the guiding cavity. 17. The ray beam guiding device according to claim 5, wherein each fin plate comprises a first portion connected to the front collimator and/or the rear collimator and a second portion extending parallel to the central axis of the guiding cavity. 18. The ray beam guiding device according to claim 3, wherein the front fin portion comprises a first fin plate and a second fin plate, and the first fin plate and the second fin plate are symmetrical with respect to the central axis of the guiding cavity. 19. The ray beam guiding device according to claim 11, wherein the front fin portion and the rear fin portion both comprise a first fin plate and a second fin plate, and the first fin plate and the second fin plate are symmetrical with respect to the central axis of the guiding cavity. 20. The ray beam guiding device according to claim 3, wherein the front fin portion consists of one fin plate located at one side of the central axis of the guiding cavity.
	claims	1. An optical device comprisingat least one optical component in a vacuum chamber,wherein the optical component emits at least one of EUV and soft X-ray radiation during a period of operation,wherein the optical component comprises a plurality of collectors,wherein each collector includes a first surface and an opposite second surface,wherein each first surface is reflective and comprises a top layer of at least one surface material,a material source comprising the at least one surface material,wherein the material source is situated on the second side of at least one of the plurality of collectors, andan activation source,wherein, when activated by the activation source, the material source deposits the at least one surface material in-situ upon the first surface of at least one of the plurality of collectors. 2. An optical device comprising:at least one optical component in a vacuum chamber,wherein the optical component emits at least one of EUV and soft X-ray radiation during a period of operation, andwherein the optical component comprises at least one reflective surface comprising a top layer of at least one surface material;an activation source;a material source comprising the at least one surface material,wherein, when activated by the activation source, the material source deposits the at least one surface material in-situ upon the at least one reflective surface of the optical component,wherein the material source is arranged to be movable away from the at least one reflecting surface during the period of operation and close to the at least one reflecting surface during pauses of operation of the optical component. 3. The optical device of claim 1, wherein the material source is situated on the second surface of multiple collectors of the plurality of collectors, and, wherein, when irradiated by the radiation source, the material source deposits the at least one surface material upon the first surfaces of the multiple collectors. 4. The optical device of claim 1, wherein the optical device activates the activation source during the period of operation of the optical component. 5. The optical device of claim 1, wherein the activation source activates the activation source during a period of non-operation of the optical component. 6. The optical device of claim 1, wherein the activation source comprises a chemical vapor source, and the material source deposits the at least one surface material by chemical vapor deposition. 7. The optical device of claim 1, wherein the activation source comprises a radiation source, and the material source is a sputter target that deposits the at least one surface material by sputter deposition when the material source is irradiated. 8. The optical device of claim 1, wherein the activation source comprises a radio frequency (RF) power supply coupled to the material source, and a gas that provides accelerated ions that discharge the at least one surface material from the material source. 9. The optical device of claim 1, wherein each collector comprises a multilayer mirror. 10. The optical device of claim 1, wherein the plurality of collectors forms a plurality of concentric shells. 11. The optical device of claim 1, further comprising a measurement device that provides a measure of reflectivity of the optical device, and wherein the optical device activates the activation source in dependence upon the measure of reflectivity. 12. The optical device of claim 2, wherein the activation source activates the activation source during the operation pauses of the optical component. 13. The optical device of claim 2, wherein the activation source comprises a chemical vapor source, and the material source deposits the at least one surface material by chemical vapor deposition. 14. The optical device of claim 2, wherein the activation source comprises a radiation source, and the material source is a sputter target that deposits the at least one surface material by sputter deposition when the material source is irradiated. 15. The optical device of claim 2, wherein the activation source comprises a radio frequency (RF) power supply coupled to the material source, and a gas that provides accelerated ions that discharge the at least one surface material from the material source. 16. The optical device of claim 2, further comprising a measurement device that provides a measure of reflectivity of the optical device, and wherein the optical device activates the activation source in dependence upon the measure of reflectivity.
047132124	summary	This invention relates to a process and apparatus for the surveillance and control of the various operations involved in the loading and unloading of the fuel in a nuclear reactor. BACKGROUND OF THE INVENTION A core of a nuclear reactor is comprised of groups of a square or hexagonal cross section, each comprising a bundle of rods comprising the fissionable material. These groups are arranged side-by-side in the core of the reactor according to a network of square or triangular channels. In order to bring about the best possible utilization of the nuclear fuel material and in order to avoid points of excessive flux, the arrangement of the groups is the object of predetermination by calculation, generally termed the loading plan of the core of the reactor. During the first loading of the core of the reactor, the fresh groups, not yet irradiated, are distributed in regions according to the different ratios of enrichment in fissionable material which are specified in such a manner as to bring about a power distribution which is as uniform as possible. After a cycle of irradiation, generally on the order of one year, each group has furnished a variable quantity of energy according to the initial ratio of enrichment of the fissionable material and according to the position occupied in the core of the reactor. It is necessary, therefore, to proceed with replacement of a certain number of groups which no longer possess but a weak potential for liberation of energy by an equal number of fresh groups. Furthermore, in order to make uniform the power distribution, new coordinates are assigned to each group, and different orientation in the core of the reactor is assigned as well. This new arrangement becomes the object of a new loading plan established by calculations, and determining for each group a new set of coordinates. In order to bring about the disposition of the groups in conformance with the new loading plan, it is necessary to proceed according to a series of manipulations for removing the spent groups, replacing the fresh groups, and exchanging the rest of the groups in the core of the reactor. Often, the reorganization of the groups in the core must be accompanied by an exchange of other components of the core, such as control rods, ion sources, clusters of plugs, of contaminants, etc. All of these operations lead to a final state for which the core of the reactor contains a mixture of irradiated groups and fresh groups corresponding to a new loading plan with, for each group of the core, position specified by new coordinates. The modifications interposed in the core of the reactor then react together in the reactor pool where there is located a buffer rack, and in the deactivation pool (also known as a spent fuel pit) where is situated the stockpile or storage racks. This set of manipulations must be carried out according to a rigorous procedure, termed a loading sequence. The loading sequence comprises a series of instructions to be carried out in rigorous order, one after the other. According to the type and size of the reactor, a loading sequence comprises a number of variable instructions, sometimes greater than 500. These instructions are given to operators of the group manipulation machines. Each instruction carries an order number, the identification of each group or component involved in the manipulation, the localization of departure and the localization of destination. The loading sequence scrupulously prepared in advance and correctly executed, leads to an actual loading plan which will be identical to the specified loading plan. It is important that the actual loading plan be verified in order to be forewarned against any loading error which could cause unacceptable hot spots and a poor utilization of nuclear fuel. Actually, the verification is twofold. In the first phase of verification, coming about at the end of the loading sequence, each group which is immersed into the core of the reactor is verified by optical means in order to assure perfect correlation between the actual loading plan and the calculated loading plan. It is necessary notably to be assurer that the identification number engraved on the head of the group corresponds to that which is specified for the particular position in the specified loading plan. According to the subjective nature of this first verification, and the inherent difficulties in reading the identification numbers due to the state of fouling of the groups or due to lack of water clarity, a second verification phase is provided after replacement in the location in the reactor. When the interior of the reactor is re-closed, the connections are re-established and the reactor, returned to nominal conditions of pressure and temperature, has exceeded the critical state, there is effected a neutron flux distribution field in the core for comparison with calculated values, and then validation of the state of the core of the reactor before increasing the pressure. If this second phase of verification reveals an error, it is necessary to recommence entirely the loading and agree to a supplementary arrest for several days. DESCRIPTION OF THE INVENTION The claimed invention eliminates the aforementioned disadvantages. It comprises a process which, upon beginning from an initial validated state, permits knowing the final state of the reactor core in an unequivocal manner due to a control and a registration of each operation effectively executed according to a loading sequence, often complex, taking account of all movements in the reactor core, in the reactor pool, across the transfer tunnel, and in the deactivation pool. This process satisfies the necessity of having at the end of the loading sequence a rigorous correlation between the actual loading plan and the calculated loading plan insofar as concerns the identity of the groups and the components and the coordinates of their localization within the core of the reactor, and in the stockpile racks of the deactivation pool. The process presents the advantage of acting as an element of independent control for the operations generally carried out manually by several operators who may, under certain conditions, not understand them. This process accounts for the x, y and z coordinates of the gripping heads of the loading machines, their angular position, the opening of the tongs, the speed of displacement of the machines, fixed or movable obstacles, irradiated elements to be removed or replaced in the core of the reactor, fresh elements to be introduced into the core, and all of the manipulations which follow in the pool of the reactor, in the stockpile pool, and in the transfer tube situated between the deactivation pool and the reactor pool. In a first application, the process departs from an initial, validated state to a final state of the core of the reactor with cancellation of all intermediate operations. A second application preserves, on the contrary, all of the intermediate operations for permitting a subsequent control in case of need. Finally, the process presents the advantage of carrying out a blank test, that is, carrying out a simulation of the preestablished loading sequence, and verifying the preestablished loading sequence leads effectively to the new specified loading plan. In a more sophisticated version, one can bring under control the motorization of the loading machines in the preestablished sequence and thus obtain a complete automation of these manipulations. The apparatus for applying this process comprises alarms which, for fixed obstacles, work in redundancy on the equipment likely to encounter trouble, and for temporary obstacles, are easy to be introduced by a new point of record of the alarm corresponding to the sides of the temporary obstacle. Each machine utilized for manipulation of the groups is provided with codes of position and of rotation of the mast, and in addition it carries means for detecting the presence of a load. All the signals generated are sent to an information processor which manages all the signals. This processor can know the position of extraction and insertion of all the elements. Due to the registration of each movement, by the informational means and for each of the pools considered, one can at any moment: edit a position map which at the end of a sequence will constitute the new loading plan of the core of the reactor and of the storage racks; PA1 know the free positions and the positions already occupied for avoiding any manipulation accidents; PA1 maintain for the future a trace of all of the operations; PA1 anticipate each step of the sequence and verify if it is possible to be executed; PA1 effectuate first of all a blank test of the entire sequence in order to verify that it will lead to the calculated loading plan; PA1 avoid all collision of a manipulated load with a fixed or movable obstacle.
054003741	abstract	A bellows-like construction which automatically extends upon immersion in water, is used to provide a relatively inexpensive water-tight enclosure for lifting equipment and the like. The lower end of the bellows is connected to the top of a rigid tubular member which extends up from a hook box or like type of structure, in a manner to form a hermetic seal. The upper end of the bellows-like arrangement is provided with a buoyant member which provides sufficient lift that, when the lifting equipment is lowered into the water to a predetermined depth, the buoyant member floats on the surface of the water in a manner which elongates a corrugated tubular portion of the arrangement and prevents radioactive water from spilling over into the box thus preventing contamination of a hook, hook block and associated apparatus which are enclosed therein.
	description	The present invention relates generally to a system and method for removing radon from the environment. Radon gas is a naturally occurring radioactive noble gas. It has long been recognized that exposure to radon gas (and radon gas “daughters” that occur as a result of radon gas decay) can pose a significant health hazard. Although testing for radon gas has been performed for many years, until recently, concern over exposure to radon gas was primarily associated with workers in the uranium mining industry or others whose work brought them in contact with uranium ore. In recent years, it has been recognized that radon gas can seep out of the ground through building foundations and can accumulate inside buildings. When radon gas accumulates in a human environment, it can be inhaled, thereby exposing the lungs to radioactivity. In accordance with an embodiment, a system is provided for collecting and removing radon from a confined area. The system includes at least one collector for collecting radon from the confined area, a plurality of radon adsorbers each connected to a corresponding power supply, a plurality of valves for diverting the collected radon through one or more of the plurality of radon adsorbers, and a plurality of radon storage units for receiving radon held by the plurality of radon adsorbers for a predetermined period of time. In accordance with an embodiment, a method is provided for collecting and removing radon from a confined area. The method includes collecting radon from the confined area via at least one collector, connecting each of a plurality of radon adsorbers to a corresponding power supply, diverting, via a plurality of valves, the collected radon through one or more of the plurality of radon adsorbers, and receiving, via a plurality of radon storage units, radon held by the plurality of radon adsorbers for a predetermined period of time. In accordance with another embodiment, a method is provided for collecting and removing radon from a confined area. The method includes incorporating a plurality of radon adsorbers within a structure of the confined area, negatively biasing the plurality of radon adsorbers within the structure, and attracting the radon on surfaces of the plurality of radon adsorbers. In accordance with another embodiment, a wearable article for repelling radon is presented. The wearable article includes an inner protective layer having an inner surface and an outer surface, the inner surface configured to contact a user and an outer protective layer configured to contact at least a portion of the outer surface of the inner protective layer. The outer protective layer repels radon. It should be noted that the exemplary embodiments are described with reference to different subject-matters. In particular, some embodiments are described with reference to method type claims whereas other embodiments have been described with reference to apparatus type claims. However, a person skilled in the art will gather from the above and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject-matter, also any combination between features relating to different subject-matters, in particular, between features of the method type claims, and features of the apparatus type claims, is considered as to be described within this document. These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. Throughout the drawings, same or similar reference numerals represent the same or similar elements. Embodiments in accordance with the present invention provide methods and devices for collecting and removing a noble gas from a confined area. The noble gas can be, e.g., radon. Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Radon's most long-lived isotope, 222Rn has a half-life of 3.8 days. This isotope of radon is formed as one intermediate step in the normal radioactive decay chain through which uranium slowly decays into a stable isotope of lead, 206Pb. Unlike all the other intermediate elements, radon is gaseous and easily inhaled. Thus, naturally-occurring radon is responsible for the majority of public exposure to ionizing radiation. Radon is often the single largest contributor to an individual's background radiation dose, and is most variable from location to location. Despite its short lifetime, some radon gas from natural sources can accumulate to far higher than normal concentrations in buildings, especially in low areas such as basements and crawl spaces due to its heavy nature. As radon itself decays, it produces new radioactive isotopes called radon daughters or decay products or radon progeny. Unlike gaseous radon itself, radon daughters are solids and stick to surfaces, such as dust particles in air. If such contaminated dust is inhaled, these particles can stick to airways of the lung and increase a risk of developing lung cancer. Embodiments in accordance with the present invention provide methods and devices for collecting and removing or sequestering radon. If radon is sequestered for a number of days, then radon could be converted to a solid which results in a 10,000 volume reduction. Embodiments in accordance with the present invention provide methods and devices for implementing air handling filters for collecting and removing or sequestering radon from a structure, such as a building. A series of biased metal meshes, gas flow collectors, and diverting valves can be used to divert gas or radon from a building or home by electrodes where they are negatively biased to collect the radon (Rn). This enables collection of Rn as opposed to simply venting it to the outdoors. Embodiments in accordance with the present invention provide methods and devices for creating a biased mesh to be incorporated or embedded within clothing, sports equipment, and first responders' gear to prevent Rn from adsorbing to the surface of such wearable articles and/or items. The majority of Radon daughter isotopes have a positive electrical charge. Thus, devices can be used to repel or attach the daughters based on their electrical charge. As a result, toxic species are not adhered to outer surfaces of clothing, equipment, and/or gear that would easily be breathed in immediately after, e.g., a fire. The biased mesh can be used in clothing or equipment or gear related to a number of recreational or sports activities, as well as in compression bonds, breathing apparatuses, where the metal mesh is positively biased to repel Rn. Embodiments in accordance with the present invention provide methods and devices for implementing metal mesh in concrete structures. For example, metal meshes can be negatively biased, to attract the radon daughters, and can be incorporated or embedded within concrete structures. Rn in the atmosphere or environment can be adsorbed onto or in proximity to the metal mesh. The polarization of the metal mesh can be maintained negatively for weeks, months, or years at a time. The half-life of 222Rn is 3.8 days. The decay products are solids. Thus, it is only necessary to maintain the Rn long enough to allow the decay process to convert radon gas to solid materials that can no longer cause a threat. Embodiments in accordance with the present invention provide methods and devices for implementing radon detectors that are made with biased meshes to collect and allow Rn to form a solid. After enough time, the meshes could either be sent to a lab to test or measured locally. It is to be understood that the present invention will be described in terms of a given illustrative architecture; however, other architectures, structures, substrate materials and process features and steps/blocks can be varied within the scope of the present invention. It should be noted that certain features cannot be shown in all figures for the sake of clarity. This is not intended to be interpreted as a limitation of any particular embodiment, or illustration, or scope of the claims. Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this invention. FIG. 1 is a filtration system for collecting and removing radon from a confined area, in accordance with an embodiment of the present invention. The filtration system 10 includes a plurality of collectors 12, 14, 16. The plurality of collectors 12, 14, 16 are configured to collect radon, from the atmosphere or environment. The filtration system 10 further includes a plurality of diverting valves 20, 22, 24. The filtration system 10 also includes a first metal mesh 40 and a second metal mesh 42. The first metal mesh 40 is connected to a first power supply 30 via cables 31 and the second metal mesh 42 is connected to a second power supply 32 via cables 33. The first metal mesh 40 is connected between the first diverting valve 20 and the second diverting valve 22, whereas the second metal mesh 42 is connected between the first diverting valve 20 and the third diverting valve 24. Radon can flow from the first diverting valve 20, via channel 5, to the first metal mesh 40 and radon can flow from the first diverting valve 20, via channel 7, to the second metal mesh 42. The filtration system 10 also includes a plurality of radon storage units 50, 52. The storage units can be, e.g., zeolite chambers 50, 52. The first zeolite chamber 50 is connected between the radon collector 14 and the second diverting valve 22, whereas the second zeolite chamber 52 is connected between the radon collector 16 and the third diverting valve 24. The zeolite chambers 50, 52 are configured to store radon 11. The filtration system 10 also includes a main air handler 60 through which air is output 62 without radon since the radon has been either attracted to the first and second metal meshes 40, 42 or sequestered within the zeolite chambers 50, 52. In operation, in a first stage, the diverting valves 20, 22, 24 are configured such that air flows through the channel 5. Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In operation, in a second stage, the diverting valves 20, 22, 24 are configured such that air flows through channel 7. Thus, the collector 12 collects air with radon and supplies it to the second metal mesh 42 via channel 7. The second metal mesh 42 is biased via the second power supply 32. For example, the second metal mesh 42 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In the meantime, the first power supply 30 is reverse biased (to be regenerated). For example, the first power supply 30 is positively biased such that the collected radon daughters is now repelled from the first metal mesh 40. The collector 14 causes the repelled radon daughters to travel to the first zeolite chamber 50 where it is stored. The radon daughters 11 travel to the first zeolite chamber 50 via channel 15. The radon daughters 11 are sequestered in the first zeolite chamber 50. After all the radon daughters 11 are repelled from the first metal mesh 40 and stored in the first zeolite chamber 50, the diverting valves 20, 22, 24 can be configured back to their original configuration. In operation, in a third stage, the diverting valves 20, 22, 24 are configured such that air flows back through channel 5 (and air supply through channel 7 is cut off). Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is once again negatively biased (switched back from the positive change in the second stage) in order to one again collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. Of course, it is contemplated that the reverse is true. For example, the first stage can involve diverting valves 20, 22, 24 to be configured such that air flows through the channel 7. Thus, the collector 12 collects air with radon and supplies it to the second metal mesh 42 via channel 7. The second metal mesh 42 is biased via the second power supply 32. For example, the second metal mesh 42 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. Thereafter, in the second stage, the diverting valves 20, 22, 24 can be configured such that air flows through channel 5. Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is negatively biased in order to collect or attract any radon detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In the meantime, the second power supply 32 is reverse biased (to be regenerated). For example, the second power supply 32 is positively biased such that the collected radon daughters are now repelled from the second metal mesh 42. The collector 16 causes the repelled radon daughters to travel to the second zeolite chamber 52 where it is stored. The radon daughters 11 travel to the second zeolite chamber 52 via channel 17. The radon daughters 11 are sequestered in the second zeolite chamber 52. After all the radon daughters 11 are repelled from the second metal mesh 42 and stored in the second zeolite chamber 52, the diverting valves 20, 22, 24 can be configured back to their original configuration. In one exemplary embodiment, a monitoring system or a detecting device can be positioned at the output of the first and second zeolite chambers 50, 52 that periodically charge another metal mesh negatively (not shown) to monitor, e.g., alpha particle emissions. In this way, it can be determined whether the zeolite of the zeolite chambers 50, 52 is full and needs to be replaced. In another exemplary embodiment, the radon daughters can be held by the metals meshes 40, 42 or the zeolite chambers 50, 52 for example for 30 days (approximately seven ½-lives). The zeolite chambers 50, 52 can be replaced every 30 days or 60 days or 90 days, etc. One skilled in the art can contemplate a plurality of different scenarios for replacing the zeolite chambers 50, 52. In another exemplary embodiment, the metal meshes 40, 42 can simply be discarded from this configuration. FIG. 2 is a biased metal mesh to be used in clothing, equipment, and gear, in accordance with another embodiment of the present invention. The metal fibers 70 can include a core 72 and a casing 74. The core 72 can be constructed from a first metal, whereas the casing 74 can be constructed from a second metal, where the first and second metals are different. When two conductors are placed together, the electrons are free to move and cause the stack to come to a same Fermi level. This leads to one of the metals being positively biased and the other negatively biased. Thus, by placing the metal with a lower Fermi level in the core 72, it leads to the metal on the outer casing 74 to become positively biased. The core metal 72 can be, e.g., a variety of different steel or steel alloys. The casing metal 74 can be, e.g., zinc (Zn). The thickness of the casing 74 can be from about 5 nm to about 100 nm. These metal fibers 70 can be combined to form a metal mesh 70′. The metal mesh 70′ can be constructed as a fabric as shown in 70″. The fabric 70″ can be used in clothing or equipment or gear. The equipment can be, e.g., recreational equipment or sports equipment or camping equipment. The gear can be, e.g., military gear or first responder gear. Of course, one skilled in the art can contemplate incorporating the biased mesh into any type of clothing, garments, articles, apparel, outfits, equipment, gear, accessories, fixtures, appliances, machinery, tools, supplies, etc. The biased mesh would prevent radon daughters from adsorbing to the surface of such items by creating a positive charge via the casing 74. This is especially important if the equipment or gear is stored for any great length of time. FIG. 3 is a metal mesh incorporated in concrete structures and connected to at least one power supply for adsorbing radon daughters, in accordance with another embodiment of the present invention. The system 80 depicts a concrete structure 82 including a plurality of rods or shafts 84 (or connecting members) that are interconnected to hold and stabilize the metal mesh 86. At least one power supply 90 can be connected to the metal mesh 86 via cables 92. When the metal mesh 86 is negatively biased by the at least one power supply 90, radon daughters 88 are adsorbed or attracted to the outer surface of the concrete structure 82. The polarization can be maintained negatively for days or weeks or months or even years. The radon 88 can be continuously collected on the outer surface of the concrete structure where it can become solid after a predetermined time period. It is only necessary to maintain the Rn long enough to allow the decay process to convert the gas to a solid that can no longer cause a threat via inhalation. FIG. 4 is a metal mesh incorporated in concrete structures and coated with a metal for adsorbing radon daughters, in accordance with another embodiment of the present invention. The system 100 depicts a concrete structure 82 including a plurality of rods or shafts 84 (or connecting members) that are interconnected to hold and stabilize the metal mesh 86. The metal mesh 86 can be coated with a plurality of metal fibers 110, where each metal fiber 110 includes a core 112 and a casing 114. The metal mesh 86 can be permanently negatively biased by the metal fibers 110 coated thereon, and thus radon daughters 88 are adsorbed or attracted to the outer surface of the concrete structure 82. The polarization can be maintained negatively for days or weeks or months or even years. The radon daughters 88 can be continuously collected on the outer surface of the concrete structure where it can become solid after a predetermined time period. The core 112 can be constructed from a different variety of steel or steel alloys. The casing metal 114 can be, e.g., iron-nickel (NiFe) alloy or nickel-phosphorus (NiP) alloy. The thickness of the casing 114 can be from about 5 nm to about 100 nm. In another exemplary embodiment, the metal meshes can be biased by other means, such as a battery or capacitor or galvanic couples. FIG. 5 is a block/flow diagram of an exemplary method for collecting and removing radon from a confined area, in accordance with an embodiment of the present invention. At block 202, a plurality of radon adsorbers are incorporated or embedded within a structure of a confined area. The structure can be, e.g., a building. At block 204, the plurality of radon adsorbers are negatively biased within the structure (via one or more power supplies or by coating the plurality of radon adsorbers with a metal having a core (first metal) and a coating (second metal)). At block 206, the radon detected within the confined area on surfaces of the plurality of radon adsorbers is attracted to the plurality of radon adsorbers. In summary, radon (Rn) daughters adsorb to negatively biased species, even though it is a neutral species itself. Rn converts to a solid within 4 days (half-life of 3.8 days). In one exemplary embodiment, surfaces of metal meshes can be modulated by, e.g., a power supply connected thereto, to attract radon and convert it to a solid by holding it biased for a predetermined period of time. Alternatively, the surfaces of metal meshes can be modulated to attract radon daughters and to concentrate it by reversing the charge of the power supply to have the radon daughters flow into zeolite chambers (or other metal mesh) for long-term storage. Once all the radon daughters have been transferred to the long-term storage units or chambers, the power supply can be reversely connected to the metal mesh so that the metal mesh is negatively biased to re-collect new Rn by one or more collectors. In another exemplary embodiment, metal mesh can be incorporated or embedded within or attached to outer surfaces of clothing or equipment or gear such that the surface charge is positive to repel Rn. The metal mesh can be constructed by cladding a metal so that the core metal pulls electrons within in order to create a positive charge on the outer surface of the mesh. In yet another exemplary embodiment, a radon detector can be constructed such that a small kit that is biased would allow collection of radon daughters and its subsequent transformation to a solid. The solid could then be detected with a detector or with a Geiger counter in the field. It will also be understood that when an element such as a layer, region or substrate is referred to as being “on” or “over” another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being “directly on” or “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements can 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. The present embodiments can include a design for an integrated circuit chip, which can be created in a graphical computer programming language, and stored in a computer storage medium (such as a disk, tape, physical hard drive, or virtual hard drive such as in a storage access network). It should also be understood that material compounds will be described in terms of listed elements, e.g., SiGe. These compounds include different proportions of the elements within the compound, e.g., SiGe includes SixGe1-x where x is less than or equal to 1, etc. In addition, other elements can be included in the compound and still function in accordance with the present embodiments. The compounds with additional elements will be referred to herein as alloys. Reference in the specification to “one embodiment” or “an embodiment” of the present invention, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment. It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This can be extended, as readily apparent by one of ordinary skill in this and related arts, for as many items listed. 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. Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, can be used herein for ease of description to describe one element's or feature's relationship to another element(s) or feature(s) as illustrated in the FIGS. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the FIGS. For example, if the device in the FIGS. 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 term “below” can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein can be interpreted accordingly. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers can also be present. It will be understood that, although the terms first, second, etc. can 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 element. Thus, a first element discussed below could be termed a second element without departing from the scope of the present concept. Having described preferred embodiments of a system and method for collecting and removing radon from the atmosphere, the environment, and or one or more confined areas (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments described which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.
059828382	claims	1. A portable pulsed neutron detection system for detection of specific elements in an object, comprising: a manually transportable probe, said probe having a pulsed neutron generator and at least one gamma ray detector; a controller operably connected to said pulsed neutron generator for varying the intensity and pulse characteristics of said pulsed neutron generator so as to emit a beam of neutrons from said generator; a data acquisition system operably connected to said at least one gamma ray detector for collecting data measured by said detector; and, means to analyze said data corresponding to fast neutron reactions, thermal neutron reactions and activation neutron reactions to determine the chemical composition of said object. a cylindrical housing containing said neutron generator and said at least one gamma ray detector; shielding material separating said gamma ray detector and said neutron generator. 2. The system of claim 1 wherein said probe is further comprised of: 3. The system of claim 2 wherein said shielding is lead. 4. The system of claim 2 wherein said shielding is bismuth. 5. The system of claim 2 wherein said shielding is positioned around said at least one gamma ray detector about 235 degrees. 6. The system of claim 2 wherein said probe is encased in a stainless steel cylindrical housing. 7. The system of claim 1 wherein said at least one gamma ray detector is bismuth germanate. 8. The system of claim 1 wherein said at least one gamma ray detector is gadolinium orthosilicate. 9. The system of claim 1 wherein said data acquisition system further comprises a computer to process signals supplied by said at least one gamma ray detector. 10. The system of claim 9 wherein said computer generates a fitted spectrum of gamma rays at each energy channel by the equation: EQU f[i]=.SIGMA..sub.k c.sub.k m.sub.k [i]+.alpha.bg[i] 11. The system of claim 10 wherein said m.sub.k [i]'s are determined by measuring the spectrum of a sample containing only one chemical element. 12. The system of claim 10 wherein said coefficients c.sub.k and .alpha. are determined by the least squares method, minimizing the general X.sup.2 equation: EQU X.sup.2 =.SIGMA..sub.i (y.sub.i -f[i]).sup.2 /.sigma..sub.i.sup.2 13. The system of claim 1 wherein said controller separates pulses from said neutron generator by between 85 and 90 microseconds. 14. The system of claim 1 wherein said pulsed neutron generator is a deuterium-tritium neutron generator. 15. The system of claim 1 wherein said generator emits neutrons at about 14 MeV. 16. The system of claim 1 wherein said generator produces pulses between about 10 kHz and 14 kHz. 17. The system of claim 1 wherein said at least one gamma ray detector measures fast neutron reactions, thermal neutron reactions and activation neutron reactions.
	description	This application is a continuation of U.S. patent application Ser. No. 16/533,761 filed Feb. 13, 2020, which is a continuation-in-part of U.S. patent application Ser. No. 15/901,788, filed Feb. 21, 2018, which is a continuation-in-part of U.S. patent application Ser. No. 15/892,240 filed Feb. 8, 2018, which is: a continuation-in-part of U.S. patent application Ser. No. 15/838,072 filed Dec. 11, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/823,148 filed Nov. 27, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/467,840 filed Mar. 23, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/402,739 filed Jan. 10, 2017, which is a continuation-in-part of U.S. patent application Ser. No. 15/348,625 filed Nov. 10, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 15/167,617 filed May 27, 2016; and a continuation-in-part of U.S. patent application Ser. No. 15/868,897 filed Jan. 11, 2018, which is a continuation of U.S. patent application Ser. No. 15/152,479 filed May 11, 2016, which is a continuation-in-part of U.S. patent application Ser. No. 14/216,788 filed Mar. 17, 2014, which is a continuation-in-part of U.S. patent application Ser. No. 13/087,096 filed Apr. 14, 2011, which claims benefit of U.S. provisional patent application No. 61/324,776 filed Apr. 16, 2010, all of which are incorporated herein in their entirety by this reference thereto. The invention relates generally to a cancer therapy imaging and/or treatment apparatus and method of use thereof. Cancer Treatment Proton therapy works by aiming energetic ionizing particles, such as protons accelerated with a particle accelerator, onto a target tumor. These particles damage the DNA of cells, ultimately causing their death. Cancerous cells, because of their high rate of division and their reduced ability to repair damaged DNA, are particularly vulnerable to attack on their DNA. Patents related to the current invention are summarized here. Proton Beam Therapy System F. Cole, et. al. of Loma Linda University Medical Center “Multi-Station Proton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989) describe a proton beam therapy system for selectively generating and transporting proton beams from a single proton source and accelerator to a selected treatment room of a plurality of patient treatment rooms. Time of Flight Detection W. A. Worstell, “Proton Radiography System Incorporating Time-of-Flight Measurement”, U.S. patent application publication no. US 2017/0258421 A1 (Sep. 14, 2017) describes a source of a proton beam at nonrelativistic energy used for imaging and detection of the proton beam using one or more time of flight detectors. Problem There exists in the art of charged particle cancer therapy a need for safe, accurate, precise, and rapid imaging of a patient and/or treatment of a tumor using charged particles. The invention relates generally a multi-beamline charged particle cancer therapy system. Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that are performed concurrently or in different order are illustrated in the figures to help improve understanding of embodiments of the present invention. The invention comprises a method and apparatus for treating a tumor of a patient, in a beam treatment center comprising a floor, with positively charged particles, comprising: (1) a synchrotron mounted to an elevated floor section above the floor of the beam treatment center; (2) a beam transport system, comprising: a first fixed-position beam transport line terminating along a first axis, a second fixed-position beam transport line terminating along a second axis within twenty degrees of ninety degrees off of the first axis, and a third fixed-position beam transport line terminating along a third axis within twenty degrees of forty-five degrees off of at least one of the first axis and the second axis, where none of the synchrotron and the beam transport system penetrate through the floor of the beam treatment center; (3) a patient positioning system, the positively charged particles transported from the synchrotron, through the beam transport system, to a position above the patient positioning system during use; and (4) an optional repositionable nozzle system connected to the first fixed-position beam transport line at a first time, connected to the second fixed-position beam transport line at a second time, and connected to the third fixed-position beam transport line at a third time, where the nozzle track forms an arc of a circle, the center of the circle comprising an isocenter, the repositionable nozzle system moveable along the nozzle track. The above described embodiment is optionally used in combination with a proton therapy cancer treatment system and/or a proton tomography imaging system. The above described embodiment is optionally used in combination with a set of fiducial marker detectors configured to detect photons emitted from and/or reflected off of a set of fiducial markers positioned on one or more objects in a treatment room and resultant determined distances and/or calculated angles are used to determine relative positions of multiple objects or elements in the treatment room. Generally, in an iterative process, at a first time objects, such as a treatment beamline output nozzle, a specific portion of a patient relative to a tumor, a scintillation detection material, an X-ray system element, and/or a detection element, are mapped and relative positions and/or angles therebetween are determined. At a second time, the position of the mapped objects is used in: (1) imaging, such as X-ray, positron emission tomography, and/or proton beam imaging and/or (2) beam targeting and treatment, such as positively charged particle based cancer treatment. As relative positions of objects in the treatment room are dynamically determined using the fiducial marking system, engineering and/or mathematical constraints of a treatment beamline isocenter is removed. In combination, a method and apparatus is described for determining a position of a tumor in a patient for treatment of the tumor using positively charged particles in a treatment room. More particularly, the method and apparatus use a set of fiducial markers and fiducial detectors to mark/determine relative position of static and/or moveable objects in a treatment room using photons passing from the markers to the detectors. Further, position and orientation of at least one of the objects is calibrated to a reference line, such as a zero-offset beam treatment line passing through an exit nozzle, which yields a relative position of each fiducially marked object in the treatment room. Treatment calculations are subsequently determined using the reference line and/or points thereon. The inventor notes that the treatment calculations are optionally and preferably performed without use of an isocenter point, such as a central point about which a treatment room gantry rotates, which eliminates mechanical errors associated with the isocenter point being an isocenter volume in practice. In combination, a method and apparatus for imaging a tumor of a patient using positively charged particles and X-rays, comprises the steps of: (1) transporting the positively charged particles from an accelerator to a patient position using a beam transport line, where the beam transport line comprises a positively charged particle beam path and an X-ray beam path; (2) detecting scintillation induced by the positively charged particles using a scintillation detector system; (3) detecting X-rays using an X-ray detector system; (4) positioning a mounting rail through linear extension/retraction to: at a first time and at a first extension position of the mounting rail, position the scintillation detector system opposite the patient position from the exit nozzle and at a second time and at a second extension position of the mounting rail, position the X-ray detector system opposite the patient position from the exit nozzle; (5) generating an image of the tumor using output of the scintillation detector system and the X-ray detector system; and (6) alternating between the step of detecting scintillation and treating the tumor via irradiation of the tumor using the positively charged particles. In combination, a tomography system is optionally used in combination with a charged particle cancer therapy system. The tomography system uses tomography or tomographic imaging, which refers to imaging by sections or sectioning through the use of a penetrating wave, such as a positively charge particle from an injector and/or accelerator. Optionally and preferably, a common injector, accelerator, and beam transport system is used for both charged particle based tomographic imaging and charged particle cancer therapy. In one case, an output nozzle of the beam transport system is positioned with a gantry system while the gantry system and/or a patient support maintains a scintillation plate of the tomography system on the opposite side of the patient from the output nozzle. In another example, a charged particle state determination system, of a cancer therapy system or tomographic imaging system, uses one or more coated layers in conjunction with a scintillation material, scintillation detector and/or a tomographic imaging system at time of tumor and surrounding tissue sample mapping and/or at time of tumor treatment, such as to determine an input vector of the charged particle beam into a patient and/or an output vector of the charged particle beam from the patient. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerated with an accelerator, and guided with a delivery system. The cancer therapy system uses the same injector, accelerator, and guided delivery system in delivering charged particles to the cancerous tumor. For example, the tomography apparatus and cancer therapy system use a common raster beam method and apparatus for treatment of solid cancers. More particularly, the invention comprises a multi-axis and/or multi-field raster beam charged particle accelerator used in: (1) tomography and (2) cancer therapy. Optionally, the system independently controls patient translation position, patient rotation position, two-dimensional beam trajectory, delivered radiation beam energy, delivered radiation beam intensity, beam velocity, timing of charged particle delivery, and/or distribution of radiation striking healthy tissue. The system operates in conjunction with a negative ion beam source, synchrotron, patient positioning, imaging, and/or targeting method and apparatus to deliver an effective and uniform dose of radiation to a tumor while distributing radiation striking healthy tissue. For clarity of presentation and without loss of generality, throughout this document, treatment systems and imaging systems are described relative to a tumor of a patient. However, more generally any sample is imaged with any of the imaging systems described herein and/or any element of the sample is treated with the positively charged particle beam(s) described herein. Charged Particle Beam Therapy Throughout this document, a charged particle beam therapy system, such as a proton beam, hydrogen ion beam, or carbon ion beam, is described. Herein, the charged particle beam therapy system is described using a proton beam. However, the aspects taught and described in terms of a proton beam are not intended to be limiting to that of a proton beam and are illustrative of a charged particle beam system, a positively charged beam system, and/or a multiply charged particle beam system, such as C4+ or C6+. Any of the techniques described herein are equally applicable to any charged particle beam system. Referring now to FIG. 1A, a charged particle beam system 100 is illustrated. The charged particle beam preferably comprises a number of subsystems including any of: a main controller 110; an injection system 120; a synchrotron 130 that typically includes: (1) an accelerator system 131 and (2) an internal or connected extraction system 134; a radio-frequency cavity system 180; a beam transport system 135; a scanning/targeting/delivery system 140; a nozzle system 146; a patient interface module 150; a display system 160; and/or an imaging system 170. An exemplary method of use of the charged particle beam system 100 is provided. The main controller 110 controls one or more of the subsystems to accurately and precisely deliver protons to a tumor of a patient. For example, the main controller 110 obtains an image, such as a portion of a body and/or of a tumor, from the imaging system 170. The main controller 110 also obtains position and/or timing information from the patient interface module 150. The main controller 110 optionally controls the injection system 120 to inject a proton into a synchrotron 130. The synchrotron typically contains at least an accelerator system 131 and an extraction system 134. The main controller 110 preferably controls the proton beam within the accelerator system, such as by controlling speed, trajectory, and timing of the proton beam. The main controller then controls extraction of a proton beam from the accelerator through the extraction system 134. For example, the controller controls timing, energy, and/or intensity of the extracted beam. The controller 110 also preferably controls targeting of the proton beam through the scanning/targeting/delivery system 140 to the patient interface module 150 or a patient with a patient positioning system. One or more components of the patient interface module 150, such as translational and rotational position of the patient, are preferably controlled by the main controller 110. Further, display elements of the display system 160 are preferably controlled via the main controller 110. Displays, such as display screens, are typically provided to one or more operators and/or to one or more patients. In one embodiment, the main controller 110 times the delivery of the proton beam from all systems, such that protons are delivered in an optimal therapeutic manner to the tumor of the patient. Herein, the main controller 110 refers to a single system controlling the charged particle beam system 100, to a single controller controlling a plurality of subsystems controlling the charged particle beam system 100, or to a plurality of individual controllers controlling one or more sub-systems of the charged particle beam system 100. In a first example, sections of individual treatment plans are combined to form the multi-modality treatment plan 5040. Generally, in the first example individual treatment plans, such as outputs from a traditional single treatment beam type treatment planning system (TPS), are combined or sections of the individual treatment plans are combined to form the multi-modality treatment plan 5040, where each of the treatment plans is for an individual beam type. More particularly, using the first beam type 5012, such as using a proton, a first treatment plan is developed; a second beam type 5014, such as a carbon particle, is used to develop a second treatment plan; a third beam type 5016, such as a helium particle or a neon particle beam, is used to develop a third treatment plan, and/or an nth treatment plan is developed using the nth beam type 5018. In one case, the multi-modality treatment plan 5040 selects treatment elements from each of the n treatment plans to treat the tumor 220. In a second case, dose distributions from individual treatment beam paths of the n treatment plans are combined to form the multi-modal treatment plan 5040. Referring now to FIG. 1B, an illustrative exemplary embodiment of one version of the charged particle beam system 100 is provided. The number, position, and described type of components is illustrative and non-limiting in nature. In the illustrated embodiment, the injection system 120 or ion source or charged particle beam source generates protons. The injection system 120 optionally includes one or more of: a negative ion beam source, a positive ion beam source, an ion beam focusing lens, and a tandem accelerator. The protons are delivered into a vacuum tube that runs into, through, and out of the synchrotron. The generated protons are delivered along an initial path 262. Optionally, focusing magnets 127, such as quadrupole magnets or injection quadrupole magnets, are used to focus the proton beam path. A quadrupole magnet is a focusing magnet. An injector bending magnet 128 bends the proton beam toward a plane of the synchrotron 130. The focused protons having an initial energy are introduced into an injector magnet 129, which is preferably an injection Lambertson magnet. Typically, the initial beam path 262 is along an axis off of, such as above, a circulating plane of the synchrotron 130. The injector bending magnet 128 and injector magnet 129 combine to move the protons into the synchrotron 130. Main bending magnets, dipole magnets, turning magnets, or circulating magnets 132 are used to turn the protons along a circulating beam path 164. A dipole magnet is a bending magnet. The main bending magnets 132 bend the initial beam path 262 into a circulating beam path 164. In this example, the main bending magnets 132 or circulating magnets are represented as four sets of four magnets to maintain the circulating beam path 164 into a stable circulating beam path. However, any number of magnets or sets of magnets are optionally used to move the protons around a single orbit in the circulation process. The protons pass through an accelerator 133. The accelerator accelerates the protons in the circulating beam path 164. As the protons are accelerated, the fields applied by the magnets are increased. Particularly, the speed of the protons achieved by the accelerator 133 are synchronized with magnetic fields of the main bending magnets 132 or circulating magnets to maintain stable circulation of the protons about a central point or region 136 of the synchrotron. At separate points in time the accelerator 133/main bending magnet 132 combination is used to accelerate and/or decelerate the circulating protons while maintaining the protons in the circulating path or orbit. An extraction element of an inflector/deflector system is used in combination with a Lambertson extraction magnet 137 to remove protons from their circulating beam path 164 within the synchrotron 130. One example of a deflector component is a Lambertson magnet. Typically the deflector moves the protons from the circulating plane to an axis off of the circulating plane, such as above the circulating plane. Extracted protons are preferably directed and/or focused using an extraction bending magnet 142 and optional extraction focusing magnets 141, such as quadrupole magnets, and optional bending magnets along a positively charged particle beam transport path 268 in a beam transport system 135, such as a beam path or proton beam path, into the scanning/targeting/delivery system 140. Two components of a scanning system 140 or targeting system typically include a first axis controller 143, such as a vertical control, and a second axis controller 144, such as a horizontal control. In one embodiment, the first axis controller 143 allows for about 100 mm of vertical or y-axis scanning of the proton beam 268 and the second axis controller 144 allows for about 700 mm of horizontal or x-axis scanning of the proton beam 268. A nozzle system 146 is used for directing the proton beam, for imaging the proton beam, for defining shape of the proton beam, and/or as a vacuum barrier between the low pressure beam path of the synchrotron and the atmosphere. Protons are delivered with control to the patient interface module 150 and to a tumor of a patient. All of the above listed elements are optional and may be used in various permutations and combinations. Ion Extraction from Ion Source For clarity of presentation and without loss of generality, examples focus on protons from the ion source. However, more generally cations of any charge are optionally extracted from a corresponding ion source with the techniques described herein. For instance, C4+ or C6+ are optionally extracted using the ion extraction methods and apparatus described herein. Further, by reversing polarity of the system, anions are optionally extracted from an anion source, where the anion is of any charge. Herein, for clarity of presentation and without loss of generality, ion extraction is coupled with tumor treatment and/or tumor imaging. However, the ion extraction is optional used in any method or apparatus using a stream or time discrete bunches of ions. Ion Extraction from Accelerator Referring now to FIG. 1C, both: (1) an exemplary proton beam extraction system 215 from the synchrotron 130 and (2) a charged particle beam intensity control system 225 are illustrated. For clarity, FIG. 1C removes elements represented in FIG. 1B, such as the turning magnets, which allows for greater clarity of presentation of the proton beam path as a function of time. Generally, protons are extracted from the synchrotron 130 by slowing the protons. As described, supra, the protons were initially accelerated in a circulating path, which is maintained with a plurality of main bending magnets 132. The circulating path is referred to herein as an original central beamline 264. The protons repeatedly cycle around a central point in the synchrotron 136. The proton path traverses through a radio frequency (RF) cavity system 310. To initiate extraction, an RF field is applied across a first blade 312 and a second blade 314, in the RF cavity system 310. The first blade 312 and second blade 314 are referred to herein as a first pair of blades. In the proton extraction process, an RF voltage is applied across the first pair of blades, where the first blade 312 of the first pair of blades is on one side of the circulating proton beam path 264 and the second blade 314 of the first pair of blades is on an opposite side of the circulating proton beam path 264. The applied RF field applies energy to the circulating charged-particle beam. The applied RF field alters the orbiting or circulating beam path slightly of the protons from the original central beamline 264 to an altered circulating beam path 265. Upon a second pass of the protons through the RF cavity system, the RF field further moves the protons off of the original proton beamline 264. For example, if the original beamline is considered as a circular path, then the altered beamline is slightly elliptical. The frequency of the applied RF field is timed to apply outward or inward movement to a given band of protons circulating in the synchrotron accelerator. Orbits of the protons are slightly more off axis compared to the original circulating beam path 264. Successive passes of the protons through the RF cavity system are forced further and further from the original central beamline 264 by altering the direction and/or intensity of the RF field with each successive pass of the proton beam through the RF field. Timing of application of the RF field and/or frequency of the RF field is related to the circulating charged particles circulation pathlength in the synchrotron 130 and the velocity of the charged particles so that the applied RF field has a period, with a peak-to-peak time period, equal to a period of time of beam circulation in the synchrotron 130 about the center 136 or an integer multiple of the time period of beam circulation about the center 136 of the synchrotron 130. Alternatively, the time period of beam circulation about the center 136 of the synchrotron 130 is an integer multiple of the RF period time. The RF period is optionally used to calculated the velocity of the charged particles, which relates directly to the energy of the circulating charged particles. The RF voltage is frequency modulated at a frequency about equal to the period of one proton cycling around the synchrotron for one revolution or at a frequency than is an integral multiplier of the period of one proton cycling about the synchrotron. The applied RF frequency modulated voltage excites a betatron oscillation. For example, the oscillation is a sine wave motion of the protons. The process of timing the RF field to a given proton beam within the RF cavity system is repeated thousands of times with each successive pass of the protons being moved approximately one micrometer further off of the original central beamline 264. For clarity, the approximately 1000 changing beam paths with each successive path of a given band of protons through the RF field are illustrated as the altered beam path 265. The RF time period is process is known, thus energy of the charged particles at time of hitting the extraction material 330, described infra, is known. With a sufficient sine wave betatron amplitude, the altered circulating beam path 265 touches and/or traverses a extraction material 330, such as a foil or a sheet of foil. The foil is preferably a lightweight material, such as beryllium, a lithium hydride, a carbon sheet, or a material having low nuclear charge components. Herein, a material of low nuclear charge is a material composed of atoms consisting essentially of atoms having six or fewer protons. The foil is preferably about 10 to 150 microns thick, is more preferably about 30 to 100 microns thick, and is still more preferably about 40 to 60 microns thick. In one example, the foil is beryllium with a thickness of about 50 microns. When the protons traverse through the foil, energy of the protons is lost and the speed of the protons is reduced. Typically, a current is also generated, described infra. Protons moving at the slower speed travel in the synchrotron with a reduced radius of curvature 266 compared to either the original central beamline 264 or the altered circulating path 265. The reduced radius of curvature 266 path is also referred to herein as a path having a smaller diameter of trajectory or a path having protons with reduced energy. The reduced radius of curvature 266 is typically about two millimeters less than a radius of curvature of the last pass of the protons along the altered proton beam path 265. The thickness of the extraction material 330 is optionally adjusted to create a change in the radius of curvature, such as about ½, 1, 2, 3, or 4 mm less than the last pass of the protons 265 or original radius of curvature 264. The reduction in velocity of the charged particles transmitting through the extraction material 330 is calculable, such as by using the pathlength of the betatron oscillating charged particle beam through the extraction material 330 and/or using the density of the extraction material 330. Protons moving with the smaller radius of curvature travel between a second pair of blades. In one case, the second pair of blades is physically distinct and/or is separated from the first pair of blades. In a second case, one of the first pair of blades is also a member of the second pair of blades. For example, the second pair of blades is the second blade 314 and a third blade 316 in the RF cavity system 310. A high voltage DC signal, such as about 1 to 5 kV, is then applied across the second pair of blades, which directs the protons out of the synchrotron through an extraction magnet 137, such as a Lambertson extraction magnet, into a transport path 268. Control of acceleration of the charged particle beam path in the synchrotron with the accelerator and/or applied fields of the turning magnets in combination with the above described extraction system allows for control of the intensity of the extracted proton beam, where intensity is a proton flux per unit time or the number of protons extracted as a function of time. For example, when a current is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In another embodiment, instead of moving the charged particles to the extraction material 330, the extraction material 330 is mechanically moved to the circulating charged particles. Particularly, the extraction material 330 is mechanically or electromechanically translated into the path of the circulating charged particles to induce the extraction process, described supra. In this case, the velocity or energy of the circulating charged particle beam is calculable using the pathlength of the beam path about the center 136 of the synchrotron 130 and from the force applied by the bending magnets 132. In either case, because the extraction system does not depend on any change in magnetic field properties, it allows the synchrotron to continue to operate in acceleration or deceleration mode during the extraction process. Stated differently, the extraction process does not interfere with synchrotron acceleration. In stark contrast, traditional extraction systems introduce a new magnetic field, such as via a hexapole, during the extraction process. More particularly, traditional synchrotrons have a magnet, such as a hexapole magnet, that is off during an acceleration stage. During the extraction phase, the hexapole magnetic field is introduced to the circulating path of the synchrotron. The introduction of the magnetic field necessitates two distinct modes, an acceleration mode and an extraction mode, which are mutually exclusive in time. The herein described system allows for acceleration and/or deceleration of the proton during the extraction step and tumor treatment without the use of a newly introduced magnetic field, such as by a hexapole magnet. Charged Particle Beam Intensity Control Control of applied field, such as a radio-frequency (RF) field, frequency and magnitude in the RF cavity system 310 allows for intensity control of the extracted proton beam, where intensity is extracted proton flux per unit time or the number of protons extracted as a function of time. Still referring FIG. 1C, the intensity control system 225 is further described. In this example, an intensity control feedback loop is added to the extraction system, described supra. When protons in the proton beam hit the extraction material 330 electrons are given off from the extraction material 330 resulting in a current. The resulting current is converted to a voltage and is used as part of an ion beam intensity monitoring system or as part of an ion beam feedback loop for controlling beam intensity. The voltage is optionally measured and sent to the main controller 110 or to an intensity controller subsystem 340, which is preferably in communication or under the direction of the main controller 110. More particularly, when protons in the charged particle beam path pass through the extraction material 330, some of the protons lose a small fraction of their energy, such as about one-tenth of a percent, which results in a secondary electron. That is, protons in the charged particle beam push some electrons when passing through extraction material 330 giving the electrons enough energy to cause secondary emission. The resulting electron flow results in a current or signal that is proportional to the number of protons going through the target or extraction material 330. The resulting current is preferably converted to voltage and amplified. The resulting signal is referred to as a measured intensity signal. The amplified signal or measured intensity signal resulting from the protons passing through the extraction material 330 is optionally used in monitoring the intensity of the extracted protons and is preferably used in controlling the intensity of the extracted protons. For example, the measured intensity signal is compared to a goal signal, which is predetermined in an irradiation of the tumor plan. The difference between the measured intensity signal and the planned for goal signal is calculated. The difference is used as a control to the RF generator. Hence, the measured flow of current resulting from the protons passing through the extraction material 330 is used as a control in the RF generator to increase or decrease the number of protons undergoing betatron oscillation and striking the extraction material 330. Hence, the voltage determined off of the extraction material 330 is used as a measure of the orbital path and is used as a feedback control to control the RF cavity system. In one example, the intensity controller subsystem 340 preferably additionally receives input from: (1) a detector 350, which provides a reading of the actual intensity of the proton beam and/or (2) an irradiation plan 360. The irradiation plan provides the desired intensity of the proton beam for each x, y, energy, and/or rotational position of the patient/tumor as a function of time. Thus, the intensity controller 340 receives the desired intensity from the irradiation plan 350, the actual intensity from the detector 350 and/or a measure of intensity from the extraction material 330, and adjusts the amplitude and/or the duration of application of the applied radio-frequency field in the RF cavity system 310 to yield an intensity of the proton beam that matches the desired intensity from the irradiation plan 360. As described, supra, the protons striking the extraction material 330 is a step in the extraction of the protons from the synchrotron 130. Hence, the measured intensity signal is used to change the number of protons per unit time being extracted, which is referred to as intensity of the proton beam. The intensity of the proton beam is thus under algorithm control. Further, the intensity of the proton beam is controlled separately from the velocity of the protons in the synchrotron 130. Hence, intensity of the protons extracted and the energy of the protons extracted are independently variable. Still further, the intensity of the extracted protons is controllably variable while scanning the charged particles beam in the tumor from one voxel to an adjacent voxel as a separate hexapole and separated time period from acceleration and/or treatment is not required, as described supra. For example, protons initially move at an equilibrium trajectory in the synchrotron 130. An RF field is used to excite or move the protons into a betatron oscillation. In one case, the frequency of the protons orbit is about 10 MHz. In one example, in about one millisecond or after about 10,000 orbits, the first protons hit an outer edge of the target material 130. The specific frequency is dependent upon the period of the orbit. Upon hitting the material 130, the protons push electrons through the foil to produce a current. The current is converted to voltage and amplified to yield a measured intensity signal. The measured intensity signal is used as a feedback input to control the applied RF magnitude or RF field. An energy beam sensor, described infra, is optionally used as a feedback control to the RF field frequency or RF field of the RF field extraction system 310 to dynamically control, modify, and/or alter the delivered charge particle beam energy, such as in a continuous pencil beam scanning system operating to treat tumor voxels without alternating between an extraction phase and a treatment phase. Preferably, the measured intensity signal is compared to a target signal and a measure of the difference between the measured intensity signal and target signal is used to adjust the applied RF field in the RF cavity system 310 in the extraction system to control the intensity of the protons in the extraction step. Stated again, the signal resulting from the protons striking and/or passing through the material 130 is used as an input in RF field modulation. An increase in the magnitude of the RF modulation results in protons hitting the foil or material 130 sooner. By increasing the RF, more protons are pushed into the foil, which results in an increased intensity, or more protons per unit time, of protons extracted from the synchrotron 130. In another example, a detector 350 external to the synchrotron 130 is used to determine the flux of protons extracted from the synchrotron and a signal from the external detector is used to alter the RF field, RF intensity, RF amplitude, and/or RF modulation in the RF cavity system 310. Here the external detector generates an external signal, which is used in a manner similar to the measured intensity signal, described in the preceding paragraphs. Preferably, an algorithm or irradiation plan 360 is used as an input to the intensity controller 340, which controls the RF field modulation by directing the RF signal in the betatron oscillation generation in the RF cavity system 310. The irradiation plan 360 preferably includes the desired intensity of the charged particle beam as a function of time and/or energy of the charged particle beam as a function of time, for each patient rotation position, and/or for each x-, y-position of the charged particle beam. In yet another example, when a current from extraction material 330 resulting from protons passing through or hitting material is measured beyond a threshold, the RF field modulation in the RF cavity system is terminated or reinitiated to establish a subsequent cycle of proton beam extraction. This process is repeated to yield many cycles of proton beam extraction from the synchrotron accelerator. In still yet another embodiment, intensity modulation of the extracted proton beam is controlled by the main controller 110. The main controller 110 optionally and/or additionally controls timing of extraction of the charged particle beam and energy of the extracted proton beam. The benefits of the system include a multi-dimensional scanning system. Particularly, the system allows independence in: (1) energy of the protons extracted and (2) intensity of the protons extracted. That is, energy of the protons extracted is controlled by an energy control system and an intensity control system controls the intensity of the extracted protons. The energy control system and intensity control system are optionally independently controlled. Preferably, the main controller 110 controls the energy control system and the main controller 110 simultaneously controls the intensity control system to yield an extracted proton beam with controlled energy and controlled intensity where the controlled energy and controlled intensity are independently variable and/or continually available as a separate extraction phase and acceleration phase are not required, as described supra. Thus the irradiation spot hitting the tumor is under independent control of: time; energy; intensity; x-axis position, where the x-axis represents horizontal movement of the proton beam relative to the patient, and y-axis position, where the y-axis represents vertical movement of the proton beam relative to the patient. In addition, the patient is optionally independently translated and/or rotated relative to a translational axis of the proton beam at the same time. Beam Transport The beam transport system 135 is used to move the charged particles from the accelerator to the patient, such as via a nozzle in a gantry, described infra. Nozzle After extraction from the synchrotron 130 and transport of the charged particle beam along the proton beam path 268 in the beam transport system 135, the charged particle beam exits through the nozzle system 146. In one example, the nozzle system includes a nozzle foil covering an end of the nozzle system 146 or a cross-sectional area within the nozzle system forming a vacuum seal. The nozzle system includes a nozzle that expands in x/y-cross-sectional area along the z-axis of the proton beam path 268 to allow the proton beam 268 to be scanned along the x-axis and y-axis by the vertical control element and horizontal control element, respectively. The nozzle foil is preferably mechanically supported by the outer edges of an exit port of the nozzle or nozzle system 146. An example of a nozzle foil is a sheet of about 0.1 inch thick aluminum foil. Generally, the nozzle foil separates atmosphere pressures on the patient side of the nozzle foil from the low pressure region, such as about 10−5 to 10−7 torr region, on the synchrotron 130 side of the nozzle foil. The low pressure region is maintained to reduce scattering of the circulating charged particle beam in the synchrotron. Herein, the exit foil of the nozzle is optionally the first tracking plane 760, tracking sheet, or sheet of the charged particle beam state determination system 250, described infra. Tomography/Beam State In one embodiment, the charged particle tomography apparatus is used to image a tumor in a patient. As current beam position determination/verification is used in both tomography and cancer therapy treatment, for clarity of presentation and without limitation beam state determination is also addressed in this section. However, beam state determination is optionally used separately and without tomography. In another example, the charged particle tomography apparatus is used in combination with a charged particle cancer therapy system using common elements. For example, tomographic imaging of a cancerous tumor is performed using charged particles generated with an injector, accelerator, and guided with a delivery system that are part of the cancer therapy system, described supra. In various examples, the tomography imaging system is optionally simultaneously operational with a charged particle cancer therapy system using common elements, allows tomographic imaging with rotation of the patient, is operational on a patient in an upright, semi-upright, and/or horizontal position, is simultaneously operational with X-ray imaging, and/or allows use of adaptive charged particle cancer therapy. Further, the common tomography and cancer therapy apparatus elements are optionally operational in a multi-axis and/or multi-field raster beam mode. In conventional medical X-ray tomography, a sectional image through a body is made by moving one or both of an X-ray source and the X-ray film in relative to the patient during the exposure. By modifying the direction and extent of the movement, operators can select different focal planes, which contain the structures of interest. More modern variations of tomography involve gathering projection data from multiple directions by moving the X-ray source and feeding the data into a tomographic reconstruction software algorithm processed by a computer. Herein, in stark contrast to known methods, the radiation source is a charged particle, such as a proton ion beam or a carbon ion beam. A proton beam is used herein to describe the tomography system, but the description applies to a heavier ion beam, such as a carbon ion beam. Further, in stark contrast to known techniques, herein the radiation source is optionally stationary while the patient is rotated. Referring now to FIG. 2, an example of a tomography apparatus is described and an example of a beam state determination is described. In this example, the tomography system 200 uses elements in common with the charged particle beam system 100, including elements of one or more of the injection system 120, the accelerator 130, a positively charged particle beam transport path 268 within a beam transport housing 261 in the beam transport system 135, the targeting/delivery system 140, the patient interface module 150, the display system 160, and/or the imaging system 170, such as the X-ray imaging system. The scintillation material is optionally one or more scintillation plates, such as a scintillating plastic, used to measure energy, intensity, and/or position of the charged particle beam. For instance, a scintillation material of scintillation detector element 205 of a scintillation detector system 210 or scintillation plate is positioned behind the patient 230 relative to the targeting/delivery system 140 elements, which is optionally used to measure intensity and/or position of the charged particle beam after transmitting through the patient. Optionally, a second scintillation plate or a charged particle induced photon emitting sheet, described infra, is positioned prior to the patient 230 relative to the targeting/delivery system 140 elements, which is optionally used to measure incident intensity and/or position of the charged particle beam prior to transmitting through the patient. The charged particle beam system 100 as described has proven operation at up to and including 330 MeV, which is sufficient to send protons through the body and into contact with the scintillation material. Particularly, 250 MeV to 330 MeV are used to pass the beam through a standard sized patient with a standard sized pathlength, such as through the chest. The intensity or count of protons hitting the plate as a function of position is used to create an image. The velocity or energy of the proton hitting the scintillation plate is also used in creation of an image of the tumor 220 and/or an image of the patient 230. The patient 230 is rotated about the y-axis and a new image is collected. Preferably, a new image is collected with about every one degree of rotation of the patient resulting in about 360 images that are combined into a tomogram using tomographic reconstruction software. The tomographic reconstruction software uses overlapping rotationally varied images in the reconstruction. Optionally, a new image is collected at about every 2, 3, 4, 5, 10, 15, 30, or 45 degrees of rotation of the patient. Herein, the scintillation material or scintillator, of the scintillation detection system, is any material that emits a photon when struck by a positively charged particle or when a positively charged particle transfers energy to the scintillation material sufficient to cause emission of light. Optionally, the scintillation material emits the photon after a delay, such as in fluorescence or phosphorescence. However, preferably, the scintillator has a fast fifty percent quench time, such as less than 0.0001, 0.001, 0.01, 0.1, 1, 10, 100, or 1,000 milliseconds, so that the light emission goes dark, falls off, or terminates quickly. Preferred scintillation materials include sodium iodide, potassium iodide, cesium iodide, an iodide salt, and/or a doped iodide salt. Additional examples of the scintillation materials include, but are not limited to: an organic crystal, a plastic, a glass, an organic liquid, a luminophor, and/or an inorganic material or inorganic crystal, such as barium fluoride, BaF2; calcium fluoride, CaF2, doped calcium fluoride, sodium iodide, NaI; doped sodium iodide, sodium iodide doped with thallium, NaI(Tl); cadmium tungstate, CdWO4; bismuth germanate; cadmium tungstate, CdWO4; calcium tungstate, CaWO4; cesium iodide, CsI; doped cesium iodide; cesium iodide doped with thallium, CsI(Tl); cesium iodide doped with sodium CsI(Na); potassium iodide, KI; doped potassium iodide, gadolinium oxysulfide, Gd2O2S; lanthanum bromide doped with cerium, LaBr3 (Ce); lanthanum chloride, LaCl3; cesium doped lanthanum chloride, LaCl3(Ce); lead tungstate, PbWO4; LSO or lutetium oxyorthosilicate (Lu2SiO5); LYSO, Lu1.8Y0.2SiO5(Ce); yttrium aluminum garnet, YAG(Ce); zinc sulfide, ZnS(Ag); and zinc tungstate, ZnWO4. In one embodiment, a tomogram or an individual tomogram section image is collected at about the same time as cancer therapy occurs using the charged particle beam system 100. For example, a tomogram is collected and cancer therapy is subsequently performed: without the patient moving from the positioning systems, such as in a semi-vertical partial immobilization system, a sitting partial immobilization system, or the a laying position. In a second example, an individual tomogram slice is collected using a first cycle of the accelerator 130 and using a following cycle of the accelerator 130, the tumor 220 is irradiated, such as within about 1, 2, 5, 10, 15 or 30 seconds. In a third case, about 2, 3, 4, or 5 tomogram slices are collected using 1, 2, 3, 4, or more rotation positions of the patient 230 within about 5, 10, 15, 30, or 60 seconds of subsequent tumor irradiation therapy. In another embodiment, the independent control of the tomographic imaging process and X-ray collection process allows simultaneous single and/or multi-field collection of X-ray images and tomographic images easing interpretation of multiple images. Indeed, the X-ray and tomographic images are optionally overlaid and/or integrated to from a hybrid X-ray/proton beam tomographic image as the patient 230 is optionally in the same position for each image. In still another embodiment, the tomogram is collected with the patient 230 in the about the same position as when the patient's tumor is treated using subsequent irradiation therapy. For some tumors, the patient being positioned in the same upright or semi-upright position allows the tumor 220 to be separated from surrounding organs or tissue of the patient 230 better than in a laying position. Positioning of the scintillation material, in the scintillation detector system 210, behind the patient 230 allows the tomographic imaging to occur while the patient is in the same upright or semi-upright position. The use of common elements in the tomographic imaging and in the charged particle cancer therapy allows benefits of the cancer therapy, described supra, to optionally be used with the tomographic imaging, such as proton beam x-axis control, proton beam y-axis control, control of proton beam energy, control of proton beam intensity, timing control of beam delivery to the patient, rotation control of the patient, and control of patient translation all in a raster beam mode of proton energy delivery. The use of a single proton or cation beamline for both imaging and treatment eases patient setup, reduces alignment uncertainties, reduces beam state uncertainties, and eases quality assurance. In yet still another embodiment, initially a three-dimensional tomographic X-ray and/or proton based reference image is collected, such as with hundreds of individual rotation images of the tumor 220 and patient 230. Subsequently, just prior to proton treatment of the cancer, just a few 2-dimensional control tomographic images of the patient are collected, such as with a stationary patient or at just a few rotation positions, such as an image straight on to the patient, with the patient rotated about 45 degrees each way, and/or the X-ray source and/or patient rotated about 90 degrees each way about the y-axis. The individual control images are compared with the 3-dimensional reference image. An adaptive proton therapy is optionally subsequently performed where: (1) the proton cancer therapy is not used for a given position based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images and/or (2) the proton cancer therapy is modified in real time based on the differences between the 3-dimensional reference image and one or more of the 2-dimensional control images. Charged Particle State Determination/Verification/Photonic Monitoring Still referring to FIG. 2, the tomography system 200 is optionally used with a charged particle beam state determination system 250, optionally used as a charged particle verification system. The charged particle state determination system 250 optionally measures, determines, and/or verifies one of more of: (1) position of the charged particle beam, such as a treatment beam 269, (2) direction of the treatment beam 269, (3) intensity of the treatment beam 269, (4) energy of the treatment beam 269, (5) position, direction, intensity, and/or energy of the charged particle beam, such as a residual charged particle beam 267 after passing through a sample or the patient 230, and/or (6) a history of the charged particle beam. For clarity of presentation and without loss of generality, a description of the charged particle beam state determination system 250 is described and illustrated separately in FIG. 3 and FIG. 4A; however, as described herein elements of the charged particle beam state determination system 250 are optionally and preferably integrated into the nozzle system 146 and/or the tomography system 200 of the charged particle treatment system 100. More particularly, any element of the charged particle beam state determination system 250 is integrated into the nozzle system 146, a dynamic gantry nozzle, and/or tomography system 200. The tomography system detects secondary electrons, resultant from the positively charged particles, and/or uses a scintillation material of a scintillation detector element 205, scintillation plate, or scintillation detector system 210. The nozzle system 146 or the dynamic gantry nozzle provides an outlet of the charged particle beam from the vacuum tube initiating at the injection system 120 and passing through the synchrotron 130 and beam transport system 135. Any plate, tracking plane, sheet, fluorophore, or detector of the charged particle beam state determination system is optionally integrated into the nozzle system 146. For example, an exit foil of the nozzle is optionally a first sheet 252 of the charged particle beam state determination system 250 and a first coating 254 is optionally coated onto the exit foil, as illustrated in FIG. 2. Similarly, optionally a surface of the scintillation material is a support surface for a fourth coating 292, as illustrated in FIG. 2. The charged particle beam state determination system 250 is further described, infra. Referring now to FIG. 2, FIG. 3, and FIG. 4(A-K), four tracking planes and/or four sheets, such as a first tracking plane 260 or a first sheet 252, a second tracking plane 270 or second sheet, a third tracking plane 280 or third sheet, and a fourth tracking plane 290 or fourth sheet are used to illustrate detection sheets and/or photon emitting sheets upon transmittance of a charged particle beam. Each sheet is optionally coated with a photon emitter, such as a fluorophore, such as the first sheet 252 is optionally coated with a first coating 254. Without loss of generality and for clarity of presentation, the four tracking planes are each illustrated as units, where the light emitting layer is not illustrated. Thus, for example, the second tracking plane 270 optionally refers to a support sheet, a light emitting sheet, and/or a support sheet coated by a light emitting element. The four tracking planes are representative of n tracking planes, where n is a positive integer. Optionally, any of the four tracking planes are optionally used a time-of-flight detectors, as described infra, with or without a proton beam detection array for determining an x/y-location of the proton beam. Referring now to FIG. 2 and FIG. 3, the charged particle beam state verification system 250 is a system that allows for monitoring of the actual charged particle beam position in real-time without destruction of the charged particle beam. The charged particle beam state verification system 250 preferably includes a first position element or first beam verification layer, which is also referred to herein as a coating, luminescent, fluorescent, phosphorescent, radiance, or viewing layer. The first position element optionally and preferably includes a coating or thin layer substantially in contact with a sheet, such as an inside surface of the nozzle foil, where the inside surface is on the synchrotron side of the nozzle foil. Less preferably, the verification layer or coating layer is substantially in contact with an outer surface of the nozzle foil, where the outer surface is on the patient treatment side of the nozzle foil. Preferably, the nozzle foil provides a substrate surface for coating by the coating layer. Optionally, a binding layer is located between the coating layer and the nozzle foil, substrate, or support sheet. Optionally, the position element is placed anywhere in the charged particle beam path. Optionally, more than one position element on more than one sheet, respectively, is used in the charged particle beam path and is used to determine a state property of the charged particle beam, as described infra. Still referring to FIG. 2 and FIG. 3, the coating, referred to as a fluorophore, yields a measurable spectroscopic response, spatially viewable by a detector or camera, as a result of transmission by the proton beam. The coating is preferably a phosphor, but is optionally any material that is viewable or imaged by a detector where the material changes, as viewed spectroscopically, as a result of the charged particle beam hitting or transmitting through the coating or coating layer. A detector or camera views secondary photons emitted from the coating layer and determines a position of a treatment beam 269, which is also referred to as a current position of the charged particle beam or final treatment vector of the charged particle beam, by the spectroscopic differences resulting from protons and/or charged particle beam passing through the coating layer. For example, the camera views a surface of the coating surface as the proton beam or positively charged cation beam is being scanned by the first axis controller 143, vertical control, and the second axis controller 144, horizontal control, beam position control elements during treatment of the tumor 220. The camera views the current position of the charged particle beam or treatment beam 269 as measured by spectroscopic response. The coating layer is preferably a phosphor or luminescent material that glows and/or emits photons for a short period of time, such as less than 5 seconds for a 50% intensity, as a result of excitation by the charged particle beam. The detector observes the temperature change and/or observe photons emitted from the charged particle beam traversed spot. Optionally, a plurality of cameras or detectors are used, where each detector views all or a portion of the coating layer. For example, two detectors are used where a first detector views a first half of the coating layer and the second detector views a second half of the coating layer. Preferably, at least a portion of the detector is mounted into the nozzle system to view the proton beam position after passing through the first axis and second axis controllers 143, 144. Preferably, the coating layer is positioned in the proton beam path 268 in a position prior to the protons striking the patient 230. Referring now to FIG. 1 and FIG. 2, the main controller 110, connected to the camera or detector output, optionally and preferably compares the final proton beam position or position of the treatment beam 269 with the planned proton beam position and/or a calibration reference, such as a calibrated beamline, to determine if the actual proton beam position or position of the treatment beam 269 is within tolerance. The charged particle beam state determination system 250 preferably is used in one or more phases, such as a calibration phase, a mapping phase, a beam position verification phase, a treatment phase, and a treatment plan modification phase. The calibration phase is used to correlate, as a function of x-, y-position of the first axis controller 143 and the second axis controller 144 response the actual x-, y-position of the proton beam at the patient interface. During the treatment phase, the charged particle beam position is monitored and compared to the calibration and/or treatment plan to verify accurate proton delivery to the tumor 220 and/or as a charged particle beam shutoff safety indicator. Referring now to FIG. 5, a position verification system 178 and/or a treatment delivery control system 112, upon determination of a tumor shift, an unpredicted tumor distortion upon treatment, and/or a treatment anomaly optionally generates and or provides a recommended treatment change 1070. The treatment change 1070 is optionally sent out while the patient 230 is still in the treatment position, such as to a proximate physician, through a communication system to a remote physician located outside of the treatment room and not in a direct line of sight of the patient in the treatment position, such as no line of sight through a window between a control room and the patient in the treatment room, and/or over the internet to a remote physician, for physician approval 1072, receipt of which allows continuation of the now modified and approved treatment plan. In a second example, the multi-modality treatment plan 5040 is directly formed using the multiple beam types 5010. Thus, instead of a traditional treatment planning system (TPS) using a single beam type, a multi-modal treatment planning system (M-TPS) is used that develops a tumor treatment plan using more than one beam type. As described, supra, optionally and preferably, the multi-modal treatment planning system incorporates dose delivery information along treatment beam paths along with scattering, dispersion, and/or delivery dosage errors along the treatment beam paths to yield a prescribed, generally uniformly distributed, tumor irradiation plan. In a third example, the process of developing the tumor irradiation plan 5000, which optionally includes an imaging step, using the set of multiple beam types 5010 incorporates physical and/or statistical treatment beam properties 5020 in generation of the multi-modality treatment plan. For instance, differing beam types have differing dispersion and/or scattering properties 5022, such as at a given depth one beam type, such as H+, scatters more around a given body constituent than a second beam type, such as C6+. In another case, resolution versus dosage 5024 is used, such as increasing/decreasing the beam energy results in, respectively, both a decreased/increased beam dosage delivered to the patient 230 and a reduced/enhanced resolution image. For instance, a lower radiation dosage is optionally and preferably used to image an immunocompromised individual, even though resolution of the image is slightly degraded, by using a higher energy beam that deposits less energy into the individual during collection of one or more images. In a fourth example, the process of developing the tumor irradiation plan 5000, which optionally includes an imaging step, using the set of multiple beam types 5010 incorporates individual patient related information 5030 in generation of the multi-modality treatment plan. A first example of individual patient related information 5030 comprises health factors 5032, such as a prior medical event or history, a sensitivity to radiation, unique anatomy and/or morphology of the individual, a current disease situation, a family record, and/or known, deduced, and/or statistical individual scattering/dispersion properties of one or more voxels of the tumor 220 and/or a potential beam path of the patient 230. A second example of individual patient related information 5030 comprises a physical state 5034 of the individual, such as a gender, a weight, a body type, a skin thickness, a bone thickness, a bone density, and/or a relative proximity of a nerve/nerve bundle and/or brain section/blood brain barrier relative to an edge of the tumor 220 of the individual 230. In a fifth example, a dose distribution plan is developed using one or more of: a superposition of dose distribution plans, a weighted superposition, such as taking into account relative effectiveness and/or relative risk of different modalities, and/or beam widths as a function of depth/pathlength for one or more of the multiple beam types 5010. In a sixth example, a higher resolution treatment beam, such as comprising first larger mass particles relative to second lower mass particles, is used to treat tumor borders/edges, such as within less than 2, 1, 0.5, 0.25, or 0.1 mm of a nerve, nerve bundle, brain/tumor barrier, blood/brain barrier, or organ while the lower mass particle is used in at least one other volume/voxel of the tumor 220 of the patient 230. In a fifth example, as illustrated the process of developing the multi-modal treatment plan 5040 is optionally, using the main controller 110 and/or treatment deliver control system (TDCS) 112, automated, semi-automated, iterative, and/or based on imaging occurring during treatment, such as during a time period or treatment session that the patient remains in the treatment room and/or remains positioned by a patient positioning system relative to a reference point in the treatment room. Relativistic Velocity As velocity of the charged particles in the charged particle beam increases, mass of the charged particles increases. Failure to compensate for the change in mass of the charged particles results in errors in velocity and depth of penetration of the charged particles into the tumor 220 and/or the patient 230. Referring again to FIGS. 4(I-L) and referring now to FIGS. 51 to 53, for clarity of presentation and without loss of generality, an example of compensating for mass increase as a function of velocity of the charged particles is provided. Particularly: (1) a proton is used to represent any positively charged particle; (2) a linear increase in current to the turning bending magnets, dipole magnets, turning magnets, or circulating magnets 132 magnets of the synchrotron 130 is used to represent any acceleration profile; (3) the acceleration of the proton up to 330 MeV is representative of acceleration to any energy and preferably to any relativistic velocity; and (4) the time of acceleration phases is representative of both faster and slower acceleration where not all of the acceleration phases are required, as further described infra. Referring now to FIG. 51, a relativistic energy compensation system 5100 is described, which is connected at least to the main controller 110 of the charged particle beam system 100. As illustrated, during a first time period, t1, energy of the charged particles, E, such as the circulating charged particles in the circulating proton beam path 264, is less than a relativistic energy, ER, and during a second time period, t2, energy of the charged particles, E, is greater than or equal to the relativistic energy, where the relativistic energy results in a mass fraction of the accelerated particle mass, PA, to a base mass of the particle, PB, at standard temperature and pressure of greater than 1.01, 1.02, 1.03, 1.04, 1.05, 1.10, 1.15, according to equation 2.ER=PA/PB (eq. 2) During the first time period, t1, acceleration of the circulating charged particles is controlled by a first acceleration protocol 5110, which preferably does not compensate for changes in particle mass as the mass change is insignificant, and during the second time period, t2, acceleration of the circulating charged particles is controlled by a second acceleration protocol 5120, which compensates for changes in particle mass. However, the first acceleration protocol 5110 optionally accounts for mass changes, where the changes in mass are not significant, which allows the second acceleration protocol 5120 to be used in both the first and second time period. Still referring to FIG. 51, during use of the first acceleration protocol 5110: (1) a first current increase 5112 is applied to the circulating magnets 132, which increases the magnetic field across the circulation beam path 264 in the circulating magnets 132; (2) the frequency of the RF-field is linearly increased 5114 to coincide with the linearly increased velocity of the circulating charged particles, such as accelerated by the accelerator 133; and (3) energy of the circulating charged particles increases non-relativistically 5116, which yields a non-relativistic velocity increase 5130 of the circulating charged particles. The process of accelerating the circulating charged particles is repeated until a relativistic velocity of the circulating charged particles is achieved, at which time the second acceleration protocol 5120 is used to further accelerate the circulating charged particles, as further described infra. Notably, the applied current to the circulating magnets 132 optionally increases in a non-linear format, which yields a non-linear increase in the frequency of the RF-field; however, the non-linear increase in the applied current still results in the non-relativistic energy increase 5116 during the first time period, t1, as changes in energy of the circulating charged particles are still accurately calculated using non-relativistic calculations. Still referring to FIG. 51, during use of the second acceleration protocol 5120: (1) a second current increase 5132 is applied to the circulating magnets 132, which is optionally an increase in current as a function of time that is the same as the first current increase 5112; (2) the frequency of the RF-field is non-linearly increased 5134 to coincide with the increased velocity of the circulating charged particles that have increased in mass; and (3) energy of the circulating charged particles increases relativistically 5136, which yields a relativistic velocity increase 5140; the relativistic increase in velocity comprising both a mass increase 5142 and a relativistic velocity increase 5144. Use of the second acceleration protocol is optionally and preferably repeated until the velocity of the circulating charged particles reaches a desired velocity/energy. Still referring to FIG. 51 and referring again to FIGS. 37(A-C), a variant of the second acceleration protocol 5120 is optionally used to account for loss of mass of the circulating charged particles in the circulation beam path 264, such as when the proton beam is decelerating by encountering a larger potential at the gap exit side 3730 relative to the gap entrance side 3720, as described supra. More generally, mass losses are optionally and preferably accounted for during a particle deceleration period, such as in the second time period, t2, while E≥ER. Still more generally, changes in mass of the circulating charged particles are optionally and preferably accounted for during acceleration or deceleration of the charged particle beam experiencing voltage drops or voltage increases across a gap in the path of the circulating charged particles. Still referring to FIG. 51 and referring now to FIG. 52, an example of a change in mass fraction of protons as a function of energy is provided. More particularly, during the first time period, t1, the mass of the proton is constant 5210 up to about 10, 15, or 20 MeV while energy of the charged particles, E, is less than a relativistic energy, ER. However, during the second time period, t2, while energy of the charged particles, E, is greater than the relativistic energy, ER, the mass of the proton is observed to increase as the energy of the proton 5220 in the accelerator is increased from 20 to 350 MeV. Still referring to FIGS. 51 and 52 and referring now to FIG. 53, an effect of relativistic velocities 5300 is illustrated. More particularly, a change in the frequency, F, of the applied radiofrequency field in the radio frequency (RF) cavity system 310 is illustrated as a function of time and energy of the proton in the circulation beam path 264. After an optional warm up period 5305, a change in the frequency, F, as a function of time is constant during a period of non-relativistic acceleration 5310, such as during the first time period, t1, when the mass of the proton is constant. As illustrated, the non-relativistic time period is from about 50 to 200 milliseconds, which is dependent upon the particular acceleration applied to the charged particles with subsequent passes through the accelerator 133 of the synchrotron, which is representative of any charged particle accelerator used to accelerate the charged particle to relativistic velocities. As the energy of the protons in the circulation beam path 264 is further increases during a relativistic time period 5320, such as the second time period, t2, the rate of increase of the frequency of the applied radiofrequency field as a function of time, dF/dt, decreases as the velocity of the proton is no longer linearly accelerating with time and energy as the mass of the proton is increasing, as observed in FIG. 52 during a time period that the mass of the proton increases 5220. Referring still to FIGS. 51 to 53 and referring again to FIGS. 41 to 4L, relativistic calculation of proton mass from time of flight determined velocity of the proton is described in terms of imaging, such as tomographic proton imaging of the tumor 220 of the patient 230. More particularly, the time of flight of the proton is determined using the time difference between the proton striking the first time of flight detector 474 and the second time of flight detector 478. The velocity of the proton is determined by the time difference and the distance between the first and second time of flight detectors, such as the first pathlength, b1, or the second pathlength, b2, when the proton path is not orthogonal to the two time of flight detectors. When the velocity is relativistic, the resultant relativistic velocity is used to determine the relativistic mass of the proton and/or the energy of the proton. As described, supra, depth of penetration of the proton into the patient 230 is energy/velocity dependent. Similarly, the author notes that for protons still traveling with energies resultant in an increased mass of the particles after passing through the patient, a residual velocity of the proton after passing through the patient is accurately translated to a residual energy of the proton beam only if an increased mass is accounted for at relativistic velocities. Thus, accuracy of computational tomography reconstruction of the tumor 220 is improved if the computational tomography accounts for mass at relativistic energies, ER. Still yet another embodiment includes any combination and/or permutation of any of the elements described herein. The main controller, a localized communication apparatus, and/or a system for communication of information optionally comprises one or more subsystems stored on a client. The client is a computing platform configured to act as a client device or other computing device, such as a computer, personal computer, a digital media device, and/or a personal digital assistant. The client comprises a processor that is optionally coupled to one or more internal or external input device, such as a mouse, a keyboard, a display device, a voice recognition system, a motion recognition system, or the like. The processor is also communicatively coupled to an output device, such as a display screen or data link to display or send data and/or processed information, respectively. In one embodiment, the communication apparatus is the processor. In another embodiment, the communication apparatus is a set of instructions stored in memory that is carried out by the processor. The client includes a computer-readable storage medium, such as memory. The memory includes, but is not limited to, an electronic, optical, magnetic, or another storage or transmission data storage medium capable of coupling to a processor, such as a processor in communication with a touch-sensitive input device linked to computer-readable instructions. Other examples of suitable media include, for example, a flash drive, a CD-ROM, read only memory (ROM), random access memory (RAM), an application-specific integrated circuit (ASIC), a DVD, magnetic disk, an optical disk, and/or a memory chip. The processor executes a set of computer-executable program code instructions stored in the memory. The instructions may comprise code from any computer-programming language, including, for example, C originally of Bell Laboratories, C++, C #, Visual Basic® (Microsoft, Redmond, Wash.), Matlab® (MathWorks, Natick, Mass.), Java® (Oracle Corporation, Redwood City, Calif.), and JavaScript® (Oracle Corporation, Redwood City, Calif.). Herein, any number, such as 1, 2, 3, 4, 5, is optionally more than the number, less than the number, or within 1, 2, 5, 10, 20, or 50 percent of the number. Herein, an element and/or object is optionally manually and/or mechanically moved, such as along a guiding element, with a motor, and/or under control of the main controller. The particular implementations shown and described are illustrative of the invention and its best mode and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional manufacturing, connection, preparation, and other functional aspects of the system may not be described in detail. Furthermore, the connecting lines shown in the various figures are intended to represent exemplary functional relationships and/or physical couplings between the various elements. Many alternative or additional functional relationships or physical connections may be present in a practical system. In the foregoing description, the invention has been described with reference to specific exemplary embodiments; however, it will be appreciated that various modifications and changes may be made without departing from the scope of the present invention as set forth herein. The description and figures are to be regarded in an illustrative manner, rather than a restrictive one and all such modifications are intended to be included within the scope of the present invention. Accordingly, the scope of the invention should be determined by the generic embodiments described herein and their legal equivalents rather than by merely the specific examples described above. For example, the steps recited in any method or process embodiment may be executed in any order and are not limited to the explicit order presented in the specific examples. Additionally, the components and/or elements recited in any apparatus embodiment may be assembled or otherwise operationally configured in a variety of permutations to produce substantially the same result as the present invention and are accordingly not limited to the specific configuration recited in the specific examples. Benefits, other advantages and solutions to problems have been described above with regard to particular embodiments; however, any benefit, advantage, solution to problems or any element that may cause any particular benefit, advantage or solution to occur or to become more pronounced are not to be construed as critical, required or essential features or components. As used herein, the terms “comprises”, “comprising”, or any variation thereof, are intended to reference a non-exclusive inclusion, such that a process, method, article, composition or apparatus that comprises a list of elements does not include only those elements recited, but may also include other elements not expressly listed or inherent to such process, method, article, composition or apparatus. Other combinations and/or modifications of the above-described structures, arrangements, applications, proportions, elements, materials or components used in the practice of the present invention, in addition to those not specifically recited, may be varied or otherwise particularly adapted to specific environments, manufacturing specifications, design parameters or other operating requirements without departing from the general principles of the same. Although the invention has been described herein with reference to certain preferred embodiments, one skilled in the art will readily appreciate that other applications may be substituted for those set forth herein without departing from the spirit and scope of the present invention. Accordingly, the invention should only be limited by the Claims included below. In an eighth example, an actual position of the cantilevered rotatable gantry system is monitored, determined, and/or confirmed using the fiducial indicators 2040, described, infra, such as a fiducial source and/or a fiducial detector/marker placed on any section of the gantry 490, patient positioning system 1350, and/or patient 230. Floor Force Directed Gantry System Referring now to FIG. 17, a wall mounted gantry system 1700 is illustrated, where a wall mounted gantry 499 is bolted to a first wall 1710, such as a first buttress, with a first set of bolts 1714, optionally using a first mounting element 1712, and mounted to a second wall 1720, such as a second buttress 1720, such a through a second mounting element 1722, with a second set of bolts 1714. The inventor notes that in this design, forces, such as a first force, F1, and a second force, F2, are directed outward into the first wall 1710 and the second wall 1720, respectively, where at least twenty percent of resolved force is along the x-axis as illustrated. Thus, the wall mounted gantry system 499 must be designed to overcome tensile stress on the bolts, greatly increasing mounting costs of the wall mounted gantry system 499. Further, the wall mounted gantry 499 design thus requires that the walls of the building are specially designed to withstand the multi-ton horizontal forces resultant from the wall mounted gantry 499. Further, as the wall mounted gantry 1700 must rotate about an axis of rotation to function, the wall mounted gantry 1700 cannot be connected to front and back walls, but rather can only be mounted to side walls, such as the first wall 1710 and the second wall 1720 as illustrated. Thus, when the wall mounted gantry 499 rotates, the center of mass of the wall mounted gantry 499 necessarily moves into a position that is not between the end mounting points, such as the first mounting element 1712 and the second mounting element 1722. With movement of the center of mass of the wall mounted gantry 499 outside of the supports, the gantry must be configured with additional systems to prevent the wall mounted gantry system 499 from tipping over. In stark contrast, referring now to FIG. 18, in a floor mounted gantry system 1800 the gantry 490 is optionally and preferably designed to rest directly onto a support, such as the floor 1310, with no requirement of a wall mounted system. As illustrated, the mass of the gantry 490 results in only downward forces, such as a third force, F3, into ground or a first pier 1810 and as a fourth force, F4, into ground and/or a second pier 1820. Generally, in the floor mounted gantry system, the center of mass of the gantry 490 is inside a footprint of the piers, such as the first pier 1810 and the second pier 1820 and maintains a footprint inside the piers even as the gantry rotates due to use of additional piers into or out of FIG. 18 and/or due to use of the counter mass in the counterweighted gantry system 1100. Referring now to FIG. 19, an example of the gantry superstructure 1600 is illustrated incorporating the gantry 490, the gantry support arm 498, the counterweight system 1120, the rotatable beamline section 138, and the rolling floor system 1300. The rotatable gantry support 1210 is illustrated with the optional hybrid cancer treatment-imaging system 1400. Further, the first pier 1810 and the second pier 1820 of the floor mounted gantry system 1800 are illustrated, which are representative of any number of underfloor gantry support elements designed to support the gantry 490, where the underfloor gantry support elements are out of a rotation path of the gantry support arm 498 and the rotatable beamline section 138. Referenced Charged Particle Path Referring now to FIG. 20, a charged particle reference beam path system 2000 is described, which starkly contrasts to an isocenter reference point of a gantry system, as described supra. The charged particle reference beam path system 2000 defines voxels in the treatment room 922, the patient 230, and/or the tumor 220 relative to a reference path of the positively charged particles and/or a transform thereof. The reference path of the positively charged particles comprises one or more of: a zero vector, an unredirected beamline, an unsteered beamline, a nominal path of the beamline, and/or, such as, in the case of a rotatable gantry and/or moveable nozzle, a translatable and/or a rotatable position of the zero vectors. For clarity of presentation and without loss of generality, the terminology of a reference beam path is used herein to refer to an axis system defined by the charged particle beam under a known set of controls, such as a known position of entry into the treatment room 922, a known vector into the treatment room 922, a first known field applied in the first axis controller 143, and/or a second known field applied in the second axis controller 144. Further, as described, supra, a reference zero point or zero point 1002 is a point on the reference beam path. More generally, the reference beam path and the reference zero point optionally refer to a mathematical transform of a calibrated reference beam path and a calibrated reference zero point of the beam path, such as a charged particle beam path defined axis system. The calibrated reference zero point is any point; however, preferably the reference zero point is on the calibrated reference beam path and as used herein, for clarity of presentation and without loss of generality, is a point on the calibrated reference beam path crossing a plane defined by a terminus of the nozzle of the nozzle system 146. Optionally and preferably, the reference beam path is calibrated, in a prior calibration step, against one or more system position markers as a function of one or more applied fields of the first known field and the second known field and optionally energy and/or flux/intensity of the charged particle beam, such as along the treatment beam path 269. The reference beam path is optionally and preferably implemented with a fiducial marker system and is further described infra.
052951669	summary	BACKGROUND OF THE INVENTION The present invention relates to a start-up range neutron monitor (SRNM) system in a nuclear power plant particularly for suppressing contamination of external noise. A nuclear power plant includes a reactor building in which is installed a reactor containment vessle in which a reactor is disposed. A structure of a known start-up range neutron monitor system in a nuclear power plant is shown in FIG. 8, and the known SRNM system of FIG. 8 comprises a neutron detector 1 arranged in a reactor, coaxial cables 3 and 4 for transferring signals detected by the neutron detector 1 to a signal processing unit 2a disposed inside a monitor 2 arranged in a central control chamber, and a preamplifier 5 disposed between these cables 3 and 4. Namely, the neutron detector 1 is operably connected to the preamplifier 5 in the reactor building through the coaxial cable 3 connecting the neutron detector 1 and the preamplifier 5 by penetrating inside the reactor containment vessel and the coaxial cable 4 connects the preamplifier 5 and the signal processing unit 2a. These coaxial cables 3 and 4 are composed of cores 3a and 4a and outer sheaths 3b and 4b for earthing, respectively. An earth circuit has one point earth structure earthed through the signal processing unit 2a. In the known start-up range neutron monitor system of FIG. 8, electric pulse signals in response to thermal neutrons in the start-up range in the reactor are detected. The thus detected signal has a weak magnitude, so that the detected amplified by the preamplifier 5 and then treated with by the signal processing unit 2a of the monitor 2. However, since the known SRNM system has a structure in which, as described above, the neutron detector 1 and the preamplifier 5 are connected through the coaxial cable 3, when the external noise is transferred to the coaxial cable 3, an S/N (signal/noise) ratio of the weak signal is extremely lowered by the external noise, thus being inconvenient. This problem will be explained in detail with reference to FIGS. 9 and 10. Supposing that the external noise is invaded into the coaxial cable 3 on the input side of the preamplifier 5 and a noise current I.sub.N is caused by the external noise in the outer sheath 3b, a circuit in such case will be modeled as that shown in FIG. 9 and an equivalent circuit is shown in FIG. 10, in which reference numeral 1' denotes a detection signal source by means of the neutron detector 1. Referring to FIGS. 9 and 10, the start-up range neutron monitor system has, as a whole, one point earth structure in the central control chamber, and the neutron detector 1 has an isolated, i.e. non-earthed, structure. For this reason, when an impedance of the coaxial cable 3 and the circuit is supposed to R.sub.C, a noise voltage V.sub.12, caused between both poles P.sub.1 and P.sub.2 of the preamplifier 5 is represented as EQU V.sub.12 =I.sub.N .multidot.R.sub.C ( 1) That is, even if the noise current I.sub.N be weak, the noise voltage V.sub.12 becomes R.sub.C times of the current I.sub.N, so that the S/N ratio of the detected weak signal of the neutron detector 1 is lowered, thus requiring a complicated signal processing circuit of the monitor 2 disposed on the output side of the preamplifier 5 and an increased load for calculation of the signal processing, thus imparting adverse influence on the signal treatment. SUMMARY OF THE INVENTION An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art and to provide a start-up range neutron monitor system capable of easily processing a neutron detection signal by improving a noise resisting property on the input side of a preamplifier disposed, for example, in a reactor building in a nuclear power plant. This and other object can be achieved according to the present invention by providing, in one aspect, a start-up range neutron monitor system for monitoring neutrons generated from a neutron source, comprising: a neutron detector disposed in a non-earthed state and adapted to detect neutrons generated from the neutron source; PA1 a coaxial cable for externally transmitting a detection signal from the neutron detector; PA1 a preamplifier incorporated on a way of the coaxial cable for amplifiying the detection signal; PA1 a signal processing unit operably connected to the preamplifier through the coaxial cable to process the detection signal amplified by the preamplifier, the coaxial cable being composed of a first cable portion connecting the neutron detector and the preamplifier on an input side of the preamplifier and a second cable portion connecting the preamplifier and the signal processing unit on an output side of the preamplifier; and PA1 a cable shield disposed so as to cover the first cable portion of the coaxial cable, PA1 wherein an earth side circuit on the signal processing unit is earthed and the cable shield is connected to an earth side circuit of the preamplifier to thereby constitute the entire system as one point earth structure. PA1 a neutron detector disposed in a non-earthed state and adapted to detect neutrons generated from the neutron source; PA1 a coaxial cable for externally transmitting a detection signal from the neutron detector, the coaxial cable being composed of a core and an outer sheath surrounding the core; PA1 a preamplifier incorporated on a way of the coaxial cable for amplifiying the detection signal; PA1 a signal processing unit operably connected to the preamplifier through the coaxial cable to process the detection signal amplified by the preamplifier, the coaxial cable being composed of a first cable portion connecting the neutron detector and the preamplifier on an input side of the preamplifier and a second cable portion connecting the preamplifier and the signal processing unit on an output side of the preamplifier; and PA1 a coil assembly including first and second coils incorporated in the core and outer sheath of the first cable portion of the coaxial cable respectively, the first and second coils having same inductance and being arranged so as to generate magnetic fluxes in directions reverse to each other. The coaxial cable is composed of a core and an outer sheath surrounding the core. The cable shield is composed of a shield cable arranged to coaxially surround the coaxial cable. The preamplifier is composed of an amplifier circuit and a casing constituting the earth side circuit of the preamplifier, the shield cable being connected to the casing. The start-up range neutron monitor system is disposed in a nuclear power plant including a reactor building, a reactor containment vessel disposed in the reactor building and a reactor disposed in the reactor containment vessel, wherein the neutron detector is disposed in the reactor, the preamplifer is disposed in the reactor building and the first cable portion of the coaxial cable penetrates the reactor containment vessel. According to this aspect of the start-up range neutron monitor system of the present invention, when an external noise is invaded into the first cable portion of the coaxial cable on the input side of the preamplifier, a noise current in the outer sheath of the coaxial cable is earthed through the most outside cable shield. That is, the noise current is directly earthed not through the outer sheath of the coaxial cable and a voltage generated to the input end of the preamplifier becomes substantially zero, so that the external noise hardly affects on the signal processing unit for the neutron detection signal. In another aspect of the present invention, there is provided a start-up range neutron monitor system for monitoring neutrons generated from a neutron source, comprising: The coil assembly comprises a ring core and a portion of the first cable portion which is wound up around the ring core. The start-up range neutron monitor system is disposed in a neuclear power plant including a reactor building, a reactor containment vessel disposed in the reactor building and a reactor disposed in the reactor containment vessel, wherein the neutron detector is disposed in the reactor, the preamplifer is disposed in the reactor building and the first cable portion of the coaxial cable penetrating the reactor containment vessel. According to this aspect of the start-up range neutron monitor system of the present invention, the inductances of the coils inserted into the core and the outer sheath of the first portion of the coaxial cable on the input side of the preamplifer are the same with each other and these coils have the magnetic flux generating directions reverse to each other. Accordingly, the insertion of the coils do not affects on the neutron detection signal by making larger an input impedance on the side of the preamplifier than those of the core and the outer sheath of the coaxial cable. Moreover, interferance of the noise current due to the external noise to the detection signal can be reduced by setting the inductance of the coil to a value larger than a value obtained by dividing the impedance of the outer sheath by an angular frequency.
047568747	summary	BACKGROUND OF THE INVENTION This invention relates to the operation and safety of water-cooled nuclear reactors, and in particular to methods for minimizing the dangers of exposure of workers to radioactive emissions during reactor shutdown. A major hazard in water-cooled nuclear reactors is the accumulation of radioactive substances in the structural portions of the reactor. During reactor shutdown, workers are exposed to stainless steel internal walls and piping surfaces, and radioactive materials retained in oxide films which have accumulated on these surfaces are a major source of radiation exposure. The introduction of certain metallic ions, including zinc, has been used to remove or lessen such deposition. Zinc however is itself a source of radioactivity in these reactors, and this radioactivity limits the effectiveness of the use of zinc. SUMMARY OF THE INVENTION The present invention provides for using zinc which has a lower content of the .sup.64 Zn isotope than naturally occurring zinc. This isotope is the isotope in greatest abundance in naturally occurring zinc, comprising approximately 50% thereof, and has a tendency to undergo neutron capture inside a nuclear reactor to produce .sup.65 Zn, in an amount proportional to the concentration of .sup.64 Zn. In accordance with the present invention, the production of .sup.65 Zn is lessened if not eliminated entirely by using zinc in which the .sup.64 Zn is either reduced in proportion to the other isotopes or entirely absent.
	claims	1. An apparatus for monitoring nuclear thermal hydraulic stability of a nuclear reactor, comprising:a calculation unit configured to calculate a stability index of a nuclear thermal hydraulic phenomenon based on nuclear instrumentation signals, the signals being outputted by a plurality of nuclear instrumentation detectors placed at regular intervals in a reactor core;a simulation unit configured to simulate the nuclear thermal hydraulic phenomenon based on a physical model by using information on an operating state of the nuclear reactor as an input condition;a limit value updating unit configured to update a limit value of the nuclear thermal hydraulic phenomenon based on a result of the simulation; anda determination unit configured to determine, based on the stability index and the limit value, whether or not to activate a power oscillation suppressing device. 2. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 1, whereinat least one model is employed as the physical model from among:a three-dimensional reactor core simulator that simulates a three-dimensional distribution of the nuclear thermal hydraulic phenomenon inside the reactor core;a plant heat balance model that simulates heat balance of a plant;a plant transition analysis code that simulates a transient characteristic of the plant; anda stability analysis code that analyzes stability of the nuclear thermal hydraulic phenomenon in an arbitrary operating state based on results of these simulations,the apparatus further comprising:a data interface unit configured to transmit the input condition and data between the respective codes; anda man machine interface unit configured to display or output an analysis result based on an instruction from an operator. 3. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 1, whereindetermination based on the stability index and the limit value is performed for at least one object among:a core stability decay ratio;a regional stability decay ratio;a decay ratio of the nuclear instrumentation signal that is representative of those grouped by characteristics of fuel assemblies placed in the reactor core;a decay ratio of the nuclear instrumentation signal that reflects a thermal hydraulic phenomenon of a most thermally severe fuel assembly; andnatural frequencies of these nuclear instrumentation signals. 4. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 1, whereinthe stability index is calculated by extracting a frequency component corresponding to power oscillations from the nuclear instrumentation signal. 5. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 4, whereinwhen a maximum amplitude that is observed or that may possibly be observed in a stage prior to shift from a stable state to an unstable state is regarded as an oscillation determination amplitude, and an average value of standard deviations of the nuclear instrumentation signals during normal operation is regarded as a background noise amplitude in the determination unit, an allowable growth rate of the amplitude defined as a ratio of the background noise amplitude to the oscillation determination amplitude is employed as a determination criterion. 6. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 4, whereina criterion for determining occurrence of the power oscillations is set in consideration of a detection delay of the nuclear instrumentation detector, an activation delay of power oscillation suppression operation, and a delay until the power oscillation suppression operation becomes effective. 7. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 6, whereinthe delays are taken into consideration based on a ratio between an oscillation period derived from the physical model and an oscillation period derived from the nuclear instrumentation signals. 8. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 1, whereinthe determination unit performs determination in consideration of a result of evaluating uncertainty of the simulation result and a result of evaluating uncertainty at an operating point where stability evaluation is performed. 9. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 8, whereinthe determination is performed with the evaluation result estimated conservatively. 10. The apparatus for monitoring nuclear thermal hydraulic stability of the nuclear reactor according to claim 1, whereina standard deviation that indicates a variation of each nuclear instrumentation signal is calculated, a standard deviation and an average value of a plurality of nuclear instrumentation signals are calculated based on the calculated standard deviation of each nuclear instrumentation signal, and the determination unit is operated based on increasing rates of these calculated results. 11. A method for monitoring nuclear thermal hydraulic stability of a nuclear reactor, comprising the steps of:calculating a stability index of a nuclear thermal hydraulic phenomenon based on nuclear instrumentation signals, the signals being outputted by a plurality of nuclear instrumentation detectors placed at regular intervals in a reactor core;simulating the nuclear thermal hydraulic phenomenon based on a physical model by using information on an operating state of the reactor as an input condition;updating a limit value of the nuclear thermal hydraulic phenomenon based on a result of the simulation; anddetermining, based on the stability index and the limit value, whether or not to activate a power oscillation suppressing device. 12. A program for monitoring nuclear thermal hydraulic stability of a reactor to be executed by a computer that performs functions of:calculating a stability index of a nuclear thermal hydraulic phenomenon based on nuclear instrumentation signals, the signals being outputted by a plurality of nuclear instrumentation detectors placed at regular intervals in a reactor core;simulating the nuclear thermal hydraulic phenomenon based on a physical model by using information on an operating state of the reactor as an input condition;updating a limit value of the nuclear thermal hydraulic phenomenon based on a result of the simulation; anddetermining, based on the stability index and the limit value, whether or not to activate a power oscillation suppressing device.
	abstract	In order to provide a coolant tank for preventing a containment from being recompressed and reheated during the cooling of the containment upon occurrence of a design basis accident and a severe accident and a passive containment cooling system comprising the same, the present invention comprises: a storage tank for storing a coolant; a division part which is arranged within the storage tank and divides the inside of the storage tank into a first storage tank and a second storage tank to separate the coolant; a first heat exchanger which is extended from the storage tank to the containment and cools the containment on the basis of the coolant; and a unidirectional valve which is provided on the division part and allows the coolant of the second storage tank to be introduced into the first storage tank when the water level of the first storage tank is reduced.
043751040	summary	BACKGROUND This invention relates generally to sealing arrangements for pool gateways, and more particularly to removable seals for use between adjoining pools in a nuclear facility. Nuclear facilities include pools for the storage and service of irradiated components. In such pools the components are submerged in water or other liquids to provide radiation shielding and cooling. These pools are often interconnected through a series of gateways to enable underwater transfer of the irradiated components. The interconnecting gateways also serve to minimize crane clearances required to move components between pools, allowing them to be moved through a gateway rather than over a pool wall. The liquid level in each of these interconnected pools must be adjusted periodically in accordance with the particular activity taking place. For example, a pool region above a reactor and an adjoining fuel pool typically are both filled with water or other effective liquid during the transfer of fuel; however, the level of liquid in the reactor pool region typically is lowered to provide for subsequent reactor maintenance, while the liquid in the fuel pool usually is kept at the higher level. To accommodate variant liquid levels in adjoining pools a barrier or seal for liquids is required in the interconnecting gateway. The required seal must be removable to retain the capacity for underwater transfer of irradiated components between pools. The seal also must be capable of remote actuation when submerged. Furthermore, the seal must include minimal permanent pool attachments which might otherwise interfere with operations or adversely affect crane clearances. In certain nuclear facilities, hinged gates have been used as gateway seals. However, hinged gates are impractical for many applications where the clearance requirements for the sweep of the hinged gates would seriously detract from the useful space of a respective pool. Other nuclear facilities have employed keyed shielding blocks removably stacked in gateways to act as barriers between interconnectable pools. These blocks provide satisfactory radiation shielding from irradiated components contained in the pools. However, the mating surfaces of the keyed blocks usually provide undesirable liquid leakage paths between the adjoining pools. Removable gates employing inflatable tubes positioned about their peripheries have also been used in the past. However, their effectiveness when used in U-shaped, or open-top gateways, such as those common in nuclear facilities is reduced because the U-shaped design provides no means to restrain the vertical movement of the liquid barrier in reaction to the expansive force of the inflatable sealing tube acting against its lower edge. Thus the expansive force of the tube useful in forming a seal between the lower portion of the gate and an associated portion of the gateway is disadvantageously spent raising the frame. Accordingly, it is an object of the present invention to provide a new and improved gateway seal between adjoining pools in a nuclear facility. Another object of the present invention is to provide a sealing device which is removably positionable in a gateway and includes remotely actuatable restraining means to enhance the seal between the sealing device and gateway. Still another object of the present invention is to provide a sealing device for use in a U-shaped gateway between interconnectable pools in a nuclear facility which includes an inflatable sealing member the expansive forces of which are counteracted on all three sides to provide an enhanced seal between the sealing arrangement and gateway. SUMMARY The above and other objects are achieved by a sealing device comprising a frame removably positionable in a gateway between adjacent interconnectable pools. A liquid impermeable pliant sheet sealed to the frame provides a barrier to liquid flow, and an inflatable sealing tube mounted in a channel about the periphery of the frame prevents leakage between the frame and the gateway. Latching devices, which restrain movement of the frame away from the bottom of the gateway and thus enhance the seal provided by the inflatable tube, are carried by the frame and are releasably engagable with the gateway by remote actuation. In a preferred embodiment, a plurality of spaced latches are provided along the bottom edge of the frame and each latch is controllable from the upper edge of the frame for releasable engagement with the bottom side of the gateway.
	claims	1. A method for forming a neutron converter layer, comprising:machining an aerogel or polymer matrix to a selected converter layer size;dissolving a neutron hardening precursor in a supercritical carbon dioxide (CO2) fluid above a temperature of 31.1 degrees Celsius and a pressure of 7.29 MPa;infusing the supercritical CO2 fluid with the dissolved neutron hardening precursor into the aerogel or polymer matrix;lowering the pressure to trap the infused neutron hardening precursor in the aerogel or polymer matrix;reducing the aerogel or polymer matrix including the trapped infused neutron hardening precursor at an elevated temperature;infusing a conductive precursor into the reduced aerogel or polymer matrix; andinfusing a secondary electron emission coefficient (SEE) element precursor into the reduced aerogel or polymer matrix. 2. The method of claim 1, wherein the neutron hardening precursor is boron or gadolinium. 3. The method of claim 2, wherein the SEE element precursor is magnesium oxide or cesium iodide. 4. The method of claim 3, wherein the neutron converter layer has a high neutron absorption cross-section, a high electron emission coefficient, and a tailored resistivity. 5. A method for forming a neutron converter layer, comprising:machining an aerogel or polymer matrix to a selected converter layer size;dissolving neutron hardening precursor, a conductive precursor, and a secondary electron emission coefficient (SEE) element precursor in a supercritical carbon dioxide (CO2) fluid above a temperature of 31.1 degrees Celsius and a pressure of 7.29 MPa;infusing the supercritical CO2 fluid with the dissolved neutron hardening precursor, conductive precursor, and SEE element precursor into the aerogel or polymer matrix;lowering the pressure to trap the infused neutron hardening precursor, conductive precursor, and SEE element precursor in the aerogel or polymer matrix; andreducing the aerogel or polymer matrix including the trapped infused neutron hardening precursor, conductive precursor, and SEE element precursor at an elevated temperature. 6. The method of claim 5, wherein the neutron hardening precursor is boron or gadolinium. 7. The method of claim 6, wherein the SEE element precursor is magnesium oxide or cesium iodide. 8. The method of claim 7, wherein the neutron converter layer has a high neutron absorption cross-section, a high electron emission coefficient, and a tailored resistivity. 9. A method for forming a neutron converter layer, comprising:forming a solution of an alkoxide solution, water, alcohol, and a basic catalyst in the presence of metal precursors;adjusting a composition of the alkoxide solution, water, alcohol, and the basic catalyst to control a rate of hydrolysis and condensation and form a metalized aerogel having radiation hardened nanoparticles and secondary electron emission coefficient (SEE) nanoparticles; anddrying the metalized aerogel having radiation hardened nanoparticles and SEE nanoparticles using a supercritical carbon dioxide (CO2) fluid at a temperature of 31.1 degrees Celsius and a pressure of 7.29 MPa to form a single layer neutron converter material. 10. The method of claim 9, wherein the metal precursors are selected from the group consisting of Gd2O3, B2O3, MgO, CsI, and any combinations thereof;wherein the radiation hardened nanoparticles include boron or gadolinium, and wherein the secondary electron emission coefficient (SEE) nanoparticles include magnesium oxide or cesium iodide. 11. The method of claim 9, further comprising adding a quantity of carbon nanotubes to adjust a resistivity of the metalized aerogel having radiation hardened nanoparticles and SEE nanoparticles. 12. The method of claim 11, wherein the neutron converter layer has a high neutron absorption cross-section, a high electron emission coefficient, and a tailored resistivity.
	description	The present invention relates to a nanotube probe utilizing nanotube as a probe needle. More particularly, the present invention relates to a nanotube probe which realizes a concrete method for fastening a nanotube to a holder, and which can be used, for instance, as a probe needle in a scanning probe microscope that picks up images of surface of samples by detecting physical or chemical actions on the sample surfaces, and it further relates to a method of manufacturing such a nanotube probe. A scanning probe microscope is a microscope in which a probe needle detects physical or chemical actions from surface atoms of a sample while it is scanned across the surface so that the image of sample surface can be generated from the detected signals. Consequently, the resolving power and measurement accuracy of the scanning probe microscope depend to a large extent on the size and physical properties of the probe needle. The use of a nanotube, typically a carbon nanotube (CNT), which is sturdy in ultra-minute diameter, for the needle probe of scanning probe microscope has made it possible to realize a high resolution. However, fastening of the nanotube on a holder to retain the needle probe has required very high level of microscopic processing technology. As far as the nanotube probe and manufacturing method thereof are concerned, the first invention was that of Cobert Daniel Tea, Dye Hongy, et al as disclosed in Patent Publication 2000-516708. Subsequently, in the course of improving said invention, the inventor of the present invention disclosed Patent Publication 2000-227435. In the patent publication 2000-516708, a nanotube is used as the probe needle for scanning probe microscope, wherein the nanotube is fastened to a protruded portion of a cantilever by means of an adhesive using an optical microscope. However, as the maximum magnification of an optical microscope is limited to 1000 to 2000 times, it was difficult, in principle, to observe directly a nanotube which is as small as 100 nm or less. Thus, it was difficult even to fix the nanotube to a certain location on the protruded portion of a cantilever, and it was still harder to control the number of fixed nanotubes as well as the orientation thereof. To make the matter worse, it often happened that more than one nanotube were fastened, causing the obtained image to become overlapped or that the angle of the probe needle set with reference to the observed surface deviated far from 90° causing erroneous image to be generated. In other words, the situation was analogous to handling nanotubes in a dark room. In an attempt to improve such a situation, the patent published 2000-227435 proposed assembly of a nanotube probe in an electron microscope while observing the nanotube directly. To be more specific, it provides a method for manufacturing nanotube probe accurately and simply by fastening the nanotube on the holder surface with coating film generated by irradiation of electron beam. FIG. 15 shows a schematic diagram of an example of a nanotube probe constructed by the above conventional technology. While being observed directly under an electron microscope, a nanotube cartridge 106 on which nanotubes are adhered and protruded portion 104 of a cantilever are placed facing each other. Subsequently, the both members are caused to approach until the base end portion 108b of the nanotube comes in contact with said protruded portion 104. Here, the nanotube 108 has the tip end portion length A that is sufficient to be used as a probe needle while the based end portion 108b has a base end portion length B. Next, when an electron beam 110 is irradiated, the impurities floating in the sample chamber of the electron microscope are decomposed, and a coating film 112 is formed with carbon substances, which are generated by re-composition of the decomposed substances. By this coating film 112, the base end portion 108b of the nanotube is fastened to said protruded portion 104 of the cantilever. As illustrated in FIG. 15, the electron beam 110 has a beam diameter that covers entirely said base end portion 108b of the nanotube. Therefore, impurities 142, 142 existing in the sample chamber are decomposed by the electron beam 110, with the generated carbon substance forming the coating film 112 that covers the base end portion 108b of the nanotube. However, said carbon substances do not only form the coating film 112, but they also are scattered because they are charged by electrons 140, 140 and repelled by each other. In addition, the debris of the carbon substances are also scattered. Thus, it often happens that impurities 136 stuck to other areas than the coating film 112, and thereby stain the protruded portion of the cantilever. Furthermore, in case that the coating is applied on the entire base end portion 108b of the nanotube, the end face diameter of the electron beam 110 is required to be very large, lowering the energy flow density, which necessitates irradiation of electron beam 110 for very long time. Furthermore, when the tip end portion length A is established at an appropriate length, the base end portion length B can sometimes be considerably long as shown in (15B). If the base portion length B is larger than the beam diameter, in order to provide full coating of the base end portion 108b, it is necessary to use a multi-step formation of the coating film 112 by moving the electron beam 110 in the direction of the arrow m. However, the larger is the covering area of the coating film, the longer would be the time for fastening operation with according increase of impurity 136 that adheres to the protruded portion of the cantilever. As the result, some of said nanotube probes were too much stained with the impurities to be offered as a commodity. FIG. 16 shows a schematic diagram of another defective nanotube probe as well as an illustration thereof in measuring operation. Once the nanotube 108 has been fastened to the protruded portion of the cantilever 104 in a state wherein the nanotube does not pass the sharp end of the protruded portion by way of one-shot coating over full length of the base end portion of the nanotube, it is impossible to correct such displacement of nanotube. Such displacement is liable to happen when the nanotubes have been arranged obliquely on the nanotube cartridge 106. Such displaced fastening of nanotube can lead to a problem that the sharp end of the protruded portion 107 may function as a probe needle as well as the end of the nanotube 108C in an AFM measurement. If the nanotube 108 is displaced from the sharp end scanning point 150 and the nanotube scanning point 152 may pick up dual image, resulting in erroneous information of sample surface 148. FIG. 17 shows a schematic diagram of a conventional cantilever having protruded portion 104 with curved side face as well as a nanotube 108. In case the side face 122 of the protruded part of the cantilever 104 is curved concavedly, it is required to fasten the nanotube 108 on the curved side face 122. With clearance between the protruded portion 104 and the nanotube 108, the overall coating film 122 can provide effective fastening only at the vicinity of the sharp tip end and the bottom of the protruded portion, leaving all other areas of coating film not contributing to fastening. As described above, there are many areas that need to be improved in the conventional overall coating method. Accordingly, the object of the present invention is to provide a nanotube probe that is fastened to a holder with strength equal to or greater than a prescribed level and that allows fastening time to be shorter, and further to provide method for manufacturing thereof. Furthermore, another object of the present invention is to provide a nanotube probe that suffers minimum adherence of impurities in fastening process, and that can be fastened with increased strength, and further provide method for manufacturing thereof. The present invention is to accomplish the above-described object. The first embodiment of the present invention is a nanotube probe comprising a holder and a nanotube fastened thereon by a coating film on a base end portion of said nanotube in such fashion that a tip end portion of said nanotube is protruded, characterized in that said coating film comprises a plurality of partial coating films fastening, respectively, a plurality of positions of said base end portion of said nanotube on a surface of said holder, and said partial coating films are separated without overlapping each other. The second embodiment of the present invention is a nanotube probe wherein each of said partial coating film is designed to satisfy a relationship of W/d≧0.1, where W represents the maximum width of a skirt of said coating film in contact with said holder in a direction perpendicular to an axis of said nanotube, and d represents a diameter of said nanotube The third embodiment of the present invention is a nanotube probe wherein each of said partial coating film is designed to satisfy a relationship of L/d≧0.3, where L represents an axial length of said partial coating film directly holding said nanotube and d represents a diameter of said nanotube. The fourth embodiment of the present invention is a nanotube probe wherein an average thickness T of said partial coating film is 1 nm or more. The fifth embodiment of the present invention is a nanotube probe wherein a protruded portion of a cantilever is used as said holder, said base end portion of said nanotube is arranged so as to contact with said protruded portion, and said partial coating film is formed on each of two or more contact areas. The sixth embodiment of the present invention is a nanotube probe wherein a side face of said protruded portion is curved up to a tip end of said protruded portion, and said partial coating films are formed at positions where said base end portion of said nanotube is in contact with said curved surface. The seventh embodiment of the present invention is a nanotube probe wherein said nanotube is arranged so as to pass through a vicinity of said sharp tip end of said protruded portion. The eighth embodiment of the present invention is a method for manufacturing a nanotube probe comprising a holder and a nanotube fastened thereon by way of a coating film on a base end portion of said nanotube in such fashion that a tip end portion is protruded, said method for manufacturing a nanotube probe characterized in that said coating film comprises at least two partial coating films, a first coating film is formed by coating partially a first fastening position of said base end portion of said nanotube while keeping said first fastening position in contact with said surface of said holder, a second partial coating film is formed by coating partially a second fastening position of said base end portion of said nanotube while keeping said second fastening position in contact with said surface of said holder, and said first and second partial coating films are separated without overlapping each other. The ninth embodiment of the present invention is the method for manufacturing said nanotube probe, wherein a protruded portion of a cantilever is used as said holder, said first partial coating film is formed at a lower position of said base end portion of said nanotube, and said second partial coating film is formed at an upper position of said base end portion of said nanotube while keeping said nanotube in such fashion that said nanotube passes through a vicinity of a sharp tip end of said protruded portion. The tenth embodiment of the present invention is the method for manufacturing said nanotube probe, wherein, in a case that a side face of said protruded portion of said cantilever is curved up to its sharp tip end, said first partial coating film is formed at said lower position of said base end portion of said nanotube, an intermediate area of said nanotube is kept in non-contact with said protruded portion, and second partial coating film is formed at a contact area where said upper position of said base end portion of said nanotube is in contact with said vicinity of said sharp tip end of said protruded portion. The eleventh embodiment of the present invention is the method for manufacturing said nanotube probe, wherein, in a case that a side face of said protruded portion of said cantilever is curved up to its sharp tip end, said first partial coating film is formed at said lower position of said base end portion of said nanotube, an intermediate area of said nanotube is forcibly bent along said curved surface, said nanotube is adjusted around said first partial coating film as a fulcrum so as to cause said nanotube to pass through said sharp tip end of said protruded portion, no matter which of said forcible bending or said passing adjustment is performed first, and said second partial coating film is formed at a contact area where said upper position of said base end portion of said nanotube is in contact with a vicinity of said sharp tip end of said protruded portion. The twelfth embodiment of the present invention is the method for manufacturing said nanotube probe, wherein said intermediate area is fastened by a third partial coating film after forming said second partial coating film. The thirteenth embodiment of the present invention is the method for manufacturing said nanotube probe according to the eighth through the twelfth embodiments, wherein each of said partial coating film is formed in an electron microscope or a focusing ion beam apparatus while observing the work directly. The fourteenth embodiment of the present invention is the method for manufacturing said nanotube probe according to the thirteenth embodiment, wherein each of said partial coating films is formed by deposit of decomposed components generated by means of an electron beam or an ion beam. The fifteenth embodiment of the present invention is the method for manufacturing said nanotube probe, wherein a size of said partial coating film is controlled by way of restricting a scanning range of said electron beam or said ion beam. According to the first embodiment of the present invention, as the nanotube is fastened to the holder by means of partial coating films, drastic reduction of time required for forming the coating film, compared to the conventional overall coating film, is made possible by making the size of the partial coating film as small as possible. A nanotube is generally hard to be visualized in entirety even under such a magnifying device as electron microscope. In particular, it is difficult even for a skilled observer to identify the end of a nanotube. Since the overall coating method requires that the furthest back end of the nanotube is visually identified in the process of coating, it involves enormous length of time for coating. On the other hand, in the case of partial coating film method, this requirement for identifying the back end of the nanotube is completely eliminated, whereby such advantages as shortened time of coating film formation and extremely simplified coating operation can be accomplished. In other words, because the operation is nothing more than applying partial coating at two positions, at the least, identified under microscope, practicability of the manufacturing operation can be improved drastically. Furthermore, although fastening the nanotube at minimum two positions on the base end portion of the nanotube is sufficient to keep the nanotube fixed, it is possible to increase the fastening points to three or four points. According to the second embodiment of the present invention, the partial coating film can have sufficient fastening strength to fix the nanotube on the holder by forming the film in such fashion that satisfies a relationship of W/d≧0.1, where W represents the maximum width of the skirt of the coating film, and d represents the diameter of the nanotube. The partial coating film is formed in rectangular, round or other arbitrary shape, and it is analogous to fixing a nanotube with a piece of band-aid, wherein the fixing strength depends on the length of the end of said band-aid adhered to the holder surface. This length of adhesion is referred to as the maximum coating film skirt width W that the inventor has first discovered to provide for the initial fastening strength as long as the width is greater than 0.1 times the nanotube diameter d. As the coating film is formed in various configuration, such as rectangular, round, oval or curved shape, the film skirt length varies depending on longitudinal positions thereon. In the present invention, we focused on the maximum skirt width of the coating film to discover the said parameter. As this discovery had defined the lower limit for the maximum coating film width, it has eliminated the necessity for excessive fastening strength experienced in the conventional coating practice. Consequently, a substantial reduction of coating time can be realized by the present invention. Although there is no upper limit for the maximum coating film skirt width, it may be set forth in consideration of the coating time. According to the third embodiment of the present invention, the partial coating film can have sufficient fastening strength to fix the nanotube on the holder surface by forming the film in such fashion that satisfies a relationship of L/d≧0.3, where L represents the coating length, and d represents the diameter of the nanotube. As mentioned earlier, the partial coating film is analogous to a piece of band-aid for fastening the nanotube on the holder. The length of the band-aid in the axial direction holding the nanotube is referred to as the coating length, which is one of the factors determining said fastening strength. Although the coating film can be formed in a variety of configurations, this coating length is simply determined. The inventor, et al has clarified that, if the coating length is 0.3 times the diameter of the nanotube, the obtained initial fastening strength would be sufficient. As this discovery has defined the lower limit for the partial coating length L, it has eliminated the necessity for excessive fastening strength experienced in the conventional coating practice. Consequently, substantial reduction of coating time can be achieved by the present invention. Although there is no upper limit for the coating length L, it may be set forth in consideration of the coating time. According to the fourth embodiment of the present invention, it is possible to provide a nanotube probe with sufficient fastening strength to endure practical use, by forming a partial coating film with the average film thickness greater than 1 nm. Although it is desirable that the partial coating film has uniform thickness, it cannot practically be completely uniform. If the film thickness were uniform, the average thickness would be equal to the measured thickness. In case that the film thickness is not uniform, the average film thickness is available for judgment. As a matter of course, the greater is the average film thickness, the stronger is the coating. However, an increase of the average coating film thickness can result in unnecessarily extended coating time. The inventor, et al have experimentally established that if the average coating film is 1 nm or more (T≧1 nm), fastening of nanotube can be secured. In the conventional overall coating film method, an unnecessarily thick film thickness has contributed to the tremendous coating time. Since the present invention allows the average film thickness to be controlled for a minimum value of 1 nm, drastic reduction of coating time as well as simplification of the film coating operation can be achieved. According to the fifth embodiment of the present invention, because a cantilever used in the atomic force microscope (called “AFM”) can be utilized as a holder, a nanotube probe can be manufactured relatively simply by fastening a nanotube on this cantilever by means of two or more partial coating films. Furthermore, as a microscopic cantilever driving apparatus incorporated in the AFM can be utilized as it is, the nanotube probe can be easily driven under control in the coating operation. In the present invention, the configuration of the protruded portion is optional so that any of pyramids or cones can be utilized. It is merely required to form partial coating films at positions where the surface of the protruded portion and the base end portion of the nanotube contact. According to the sixth embodiment of the present invention, a protruded portion of a cantilever formed curvedly can be used as a holder. In the conventional semi-conductor, since the protruded portion is designed to be used as a probe needle, the protruded portion is sometimes formed to have curved, either concaved or convexed, side face in order to make its end sharper. In this invention, it is noted that when a bar shaped nanotube is placed in contact with said curved surface, there exists at least two points in the upper and lower positions, where partial coating film can be formed to fasten the nanotube. Thus, in case there is more than one contact points, the present invention can be effectively utilized to achieve approximately the same fastening strength as in the case of overall coating. According to the seventh embodiment of the present invention, the nanotube is fastened to the protruded portion of the cantilever in such fashion that it passes through the vicinity of the sharp tip end of the protruded portion, so that highly accurate image of sample surface can be obtained through the surface signals from the nanotube probe needle scanned over the sample surface. With the sharp tip end of the protruded portion being prevented from functioning as a probe needle, the problem of dual exposure can be eliminated. The eighth embodiment of the present invention provides a method of manufacturing to realize said first embodiment. This method comprises first selecting at least two points on the base end portion of a nanotube that are in contact with a holder and fastening these parts by forming partial coating films at these positions referred to as the first fastening position and the second fastening position, no matter whichever position is fastened first. As the partial coating films occupies by far smaller coating area than the overall coating method, the present invention provides a benefit of dramatic reduction of coating time. Generally, the fastening strength of a nanotube is dependent upon the area of coating film. However, if said relationship of W/d≧0.1, L/d≧0.3 and/or T≧1 (nm) is taken into consideration, it is possible to design the fastening strength to have a prescribed value or more by establishing a minimum area of the partial coating films. According to the ninth embodiment of the present invention, after the first partial coating film is formed on the lower position, the nanotube is tilted clockwise or counterclockwise around the first partial coating film as the fulcrum so that the nanotube passes through the sharp tip end of the protruded portion of the cantilever, thereafter the second partial coating film is formed. Such a two-stepped fastening method allows the nanotube to be placed properly so that the defect ratio of the nanotube probe can be reduced substantially. Furthermore, since a nanotube probe thus made permits only the nanotube probe needle to scan the sample surface to pick up surface signals for forming surface images, it is made possible to manufacture such nanotube probe that would not cause double exposure by the sharp tip end of the protruded portion of the cantilever. According to the tenth embodiment of the present invention, a nanotube probe can be manufactured by the use of a cantilever with a protruded portion curved for increased sharpness of its tip end. In the case that a straight nanotube bar is fit on a concavedly curved surface, the nanotube contacts the curved surface at two, lower and upper, points, leaving the intermediate area non-contact. With the nanotube placed as such, first a partial coating film is applied on the lower contact point. Then the nanotube is tilted clockwise or counterclockwise around the first partial coating film as the fulcrum so that the nanotube passes through said sharp tip end, and subsequently another partial coating film is applied on the upper contact point. Thus, these two partial coating films can fasten the nanotube firmly, even though the intermediate area is left free of contact. Furthermore, in case of convexedly curved surface, while the intermediate area of the nanotube is in contact with the surface, two partial coating films on the lower and the upper positions can fasten the nanotube firmly. At the same time, because the attitude of the nanotube is corrected certainly, defect ratio of the nanotube probes can be reduced drastically. As the sharp tip end of the protruded portion is prevented from functioning as a probe needle, double exposure is precluded. According to the eleventh embodiment of the present invention, because the nanotube is fastened to the curved surface of the protruded portion of the cantilever while the former is forcibly bent along, and attach to, the latter, the fastening strength is reinforced by the Van der Waals force acting between the nanotube and the protruded portion of the cantilever. The curved surface of the protruded portion is either concaved or convexed. In either case, when the base end portion of the nanotube is forcibly bent along the curved surface, the tip end portion of the nanotube is oriented toward the direction of protrusion of the protruded portion, whereby the nanotube probe needle tends to be placed perpendicular to the sample surface. Thus, in scanning the sample surface, the nanotube probe can follow steep indentations and protrusions on the sample surface, allowing the image of sample surface to be picked up more accurately. Furthermore, as the attitude of the nanotube is forcibly corrected, defect ratio of the nanotube probes can be reduced drastically. According to the twelfth embodiment of the present invention, as a partial coating film, or films, is provided on the intermediate area in said eleventh embodiment, the nanotube is fastened at three positions or more, which enable to realize stronger fastening. According to the thirteenth embodiment of the present invention, as an electron microscope and focusing ion beam apparatus are employed to make it possible to work on the cantilever and nanotube while directly observing them under magnification, highly accurate assembly is made available. According to the fourteenth embodiment of the present invention, the use of electron beam or ion beam to decompose the impurities in the equipment, letting decomposed substances deposit is beneficial in that a partial coating film can be formed easily in short time. Another benefit is that for said electron beam and ion beam, a ready made electron microscope and focusing ion beam apparatus (FIB apparatus) can be used without requiring any new charged beam generator. According to the fifteenth embodiment of the present invention, the size of the coating, i.e. the coating length L, the maximum coating skirt width W can be freely changed by regulating the scanning range (beam oscillation width) of the electron beam or ion beam. Thus, said conditions, W/d≧0.1 and L/d≧0.3, can be easily satisfied. Furthermore, as it is possible to minimize the beam diameter of the electron beam or the ion beam, it can effectively minimize deposition of decomposed substances on other area than the coating area. In addition, since the average coating film thickness can be controlled by regulating the beam irradiation time, said condition of film thickness, i.e. T≧1 (nm) can be easily achieved. The inventor of the present invention and his team have made strenuous development efforts to improve the nanotube probe constructed by the overall coating method, with a result that a nanotube probe by way of partial coating films have been completed. Following are more detailed description of the present invention related to nanotube probes and manufacturing method thereof with reference to the accompanying drawings. This partial coating method provides for a nanotube probe and manufacturing method thereof, wherein a nanotube can be fastened to a surface of a holder in short time, the amount of impurities adhering to the holder surface can be reduced to a bare minimum, and an arbitrary shape of holder can be used. In the following description of embodiments, a protruded portion of a cantilever used for AFM is used as a holder on which a nanotube is fastened. However, the holder is not limited to cantilevers, but any other component on which a nanotube can be fastened and which allows the nanotube to be controlled minutely may, of course, be used. FIG. 1 is an outlined structural diagram of a device used to fasten the nanotube 8 on the cantilever 2. The cantilever 2 used for AFM is composed of a cantilever portion 3 and protruded portion 4 that is used as a holder for fastening a nanotube. A plurality of nanotubes 8 are adhered to a nanotube cartridge 6, which is a source of supply of nanotubes. In order to assemble a nanotube probe, one of the nanotubes 8 on the nanotube cartridge 6 is fastened to said protruded portion 4, and subsequently the nanotube 8 is pulled away from the nanotube cartridge 6. As a matter of course, the nanotubes 8,8 are not fixed on the nanotube cartridge 6, but merely adhered thereto. The cantilever 2 can be driven in three directions, XYZ, while the nanotube cartridge 6 can be moved in two directions, XY. Since the operation is conducted in a real time observation under a scanning electron microscope, it has been made possible to ensure extremely minute control of driving. FIG. 2 is an explanatory diagram showing the procedure for fastening the nanotube 8. As illustrated in (2A), the cantilever is first driven in the direction of the arrow a while observing directly under an electron microscope, so as to have the sharp tip end 7 of the protruded portion 4 of the cantilever approach said nanotube 8 until they are minutely close to each other. In so doing, said nanotube 8 is divided by the protruded portion 4 of the cantilever into a tip end portion 8a and a base end portion 8b. Once said base end portion of the nanotube 8b has come in contact with said protruded portion 4 of the cantilever, an electron beam 10 is irradiated on a first fastening position selected arbitrarily to form a first partial coating film 12a. In the case of observation under an electron microscope, a high degree of skill is required to identify the end of the nanotube 8c. That is the reason why said first coating film 12a is formed at a position a certain distance away from the end of the nanotube 8c. In the next process shown in (2B), a second partial coating film is formed by applying irradiation of an electron beam on a second fastening position 12b which is located on the upper area of the base end portion 8b. Thus, the base end portion of the nanotube 8b is fastened to the protruded portion 4 of the cantilever. The first and second partial coating films are formed by deposit of decomposed components generated through irradiation of an electron beam on the impurities in the electron microscope. In case said impurity gas is an organic gas, the deposit of decomposed components is often constituted by carbon substances. On the other hand, in case a metallic organic gas is employed, the deposit of decomposed component is constituted by a metallic substance. Thus, the material that constitutes the coating film can be selected arbitrarily. After both the first partial coating film 12a and the second partial coating film 12b have been formed, said protruded portion 4 of the cantilever and the nanotube cartridge 6 are separated from each other in the direction of the arrow b. Here, as a matter of course, the adhesive strength between the nanotube 8 and the nanotube cartridge 6 is weaker than the fastening strength of the first partial coating film 12a and the second partial coating film 12b. Consequently, in said separating process, the nanotube 8 as integrated with the protruded portion 4 of the cantilever, is separated from the nanotube cartridge 6. FIG. 3 is an explanatory diagram illustrating a method for forming a coating film 12 by way of the electron beam 10. There are two methods for forming a coating film. The first method uses an extremely thin electron beam scanned over a prescribed scanning range which is variable for adjusting the size of the coating film. The second method uses a much larger electron beam of which diameter is variable for adjusting the size of the coating film. Said first method, as shown in (3A), employs an electron beam 10 of which diameter is narrowed down to the extreme (e.g. several nm to 10 nm). By oscillating this electron beam 10 within a prescribed scanning range, the coating film 12 is formed. For example, if the beam diameter R is 4 nm and the scanning range is preset as a square of 20 nm across, the size of the coating film 12 obtained is approximately 30 nm across. The size of the coating film 12 is in the same order as the size of the scanning range 14, but not necessarily identical. Nevertheless, there exists a certain dependence relationship between the size of scanning range 14 and the size of the coating film 12. Said scanning range 14 is an area defined by side width u and longitudinal width v realized by a deflecting coil. The coating film 12 is formed by oscillating the irradiation of the electron beam 10 within the scanning range 14. Furthermore, by changing the scanning range size, the size of the coating film can be controlled. Depending on the diameter of the nanotube to be fastened, the scanning range may be enlarged or narrowed down. Since the width D, the length L and the average thickness T of the coating film 12 are respectively subject to certain relationship with the nanotube diameter d, as discussed later, it is possible to ensure desired strength of fastening by forming a coating film in such manner that would satisfy these relationships. In (3B), the second method is utilized, wherein the diameter R of the electron beam 10 is adjusted from a small to a larger diameter with the change of aperture in accordance with the change of the nanotube diameter d from small to larger. Here, the electron beam 10 is in a state of direct irradiation without scanning. In other words, in response to change of the nanotube diameter 8 from thin (left) to thick (right), the beam diameter R of the electron beam 10 can be adjusted, so that a partial coating film 12, 12 with desired fastening strength may be obtained through irradiation thereof. As the result, the average thickness T, the coating length L and the maximum skirt width W of the partial coating film 12, as discussed in more details later, can be freely changed in accordance with the nanotube diameter d as well as the configuration of the holder surface. As a third method, it is also possible to combine adjustable beam scanning range and adjustable beam diameter R by variable aperture. For instance, in order to form a square coating film of 100 nm across, it is considered appropriate to use an electron beam diameter R of 30 nm together with a beam scanning range of 80 nm across. It goes without saying that such two-stepped adjustment can be changed freely in accordance with particular purposes. As far as the material of the partial coating film is concerned, it is possible to select such a material that would provide required properties such as fastening strength, conductivity, insulating performance, magnetic characteristics, etc. In case an organic gas is used as the impurity gas in the electron microscope chamber, said partial coating film is made of carbon substances generated by decomposition due to electron beam. In case a metallic organic gas is used as the impurity gas, said partial coating film 12 is composed of a metallic substance decomposed. It is possible to adjust said properties of the coating film by selecting the metallic elements. FIG. 4 is an explanatory diagram showing relationship between the size of the partial coating film 12 and the nanotube diameter d. As shown in (4A), the partial coating film 12 is dimensionally defined as follows. The length in the direction perpendicular to the nanotube of the area wherein the coating film is in contact with the protruded portion 4 of the cantilever is referred to as the “coating skirt width”. As the partial coating film 12 here is rectangular, the coating skirt width is constant, hence the maximum coating skirt width is equal to the coating skirt width. Therefore, this diameter may be called either the coating skirt width of the maximum coating skirt width. The length of the coating film in the axial direction is referred to as the coating length L. In this case, since the coating film is rectangular in shape, the width of the partial coating film 12 is same as said coating length L. The nanotube diameter is expressed as d, and the average film thickness T. In an effort to investigate into the relationship between the size of the partial coating film 12 and the fastening strength with reference to the nanotube diameter d, a series of durability test was conducted as shown in (4B). In this durability test, a nanotube 8 fastened to a protruded portion 4 of a cantilever 2 by a first partial coating film 12a and a second partial coating film 12b was used. The cantilever was first placed in such position that the tip end 8c of the nanotube 8 came in contact with a sample surface 48, then the cantilever was further approached in the direction of arrow C perpendicular to the sample surface so as to bend the nanotube 8. Subsequently, while keeping such bent state, the nanotube 8 was moved over the sample surface 48. After completion of 100 cycles of such movement, the fastening strength of the partial coating film 12 was measured. The test results are as summarized in FIG. 5. Although the dimensions of a rectangular partial coating film are defined in (4A), the shape of the partial coating film is not limited to rectangular or square. Instead, it is possible to form the partial coating film in various shapes in accordance with the configuration of the protruded portion of cantilever, by changing the shape of the beam section of the electron beam and/or the shape of the scanning range. As an example, an oval shaped coating film 12 is shown in (4C). Here, in the contact area between the partial coating film 12 and the surface 5 of the protruded portion, the largest length in the direction perpendicular to the nanotube from the nanotube to the end of the coating film is defined as the maximum coating skirt width. Furthermore, the axial length of the coating portion directly holding the nanotube 8 is referred to as the coating length L. The shape of the partial coating film on the nanotube probe specimen used in the durability test shown in (4B) was not limited to rectangular, but inclusive of oval shape, etc. However, a test has demonstrated that the relationship between the ratio of the maximum coating skirt width W and the coating length L to the nanotube diameter d and the nanotube fastening strength was virtually consistent at least among the rectangular and oval shapes of the coating films. From this, it can be concluded that the relationship between the respective dimensions and the nanotube diameter as shown in FIG. 5 generally hold true unless the coating film shape is excessively different. FIG. 5 shows the resultant relationship between respective dimensions of the partial coating films, as related to the nanotube diameter d, and the fastening strength. The fastening strength was graded into four levels; excellent (⊚), good (◯), acceptable (Δ), and unacceptable (X). The former three levels, excellent, good and acceptable levels are judged to be satisfactory, whereas the unacceptable level is rejected. In order to make the above judgment, the tested nanotube probes were subjected to an AFM image photography test for evaluation of visibility by skilled personnel. In the case of unacceptable level, various causes such as early dislodging of nanotube and wear on the tip end of nanotube are conceivable. In (5A), various ratio of the maximum coating skirt width W to the nanotube diameter d were evaluated. In the case of W/d=0.1, the nanotube probe was found unacceptable, while W/d=0.3 or more was found to be acceptable. In other words, in order that said partial coating film provides minimum required fastening strength for a probe needle, W/d ≧0.3 must be satisfied. Furthermore, W/d≧0.5 produced a desirable fastening strength, and W/d≧1 would be still more desirable. In (5B), various ratios of coating length L to the nanotube diameter d were evaluated. In the case of L/d=0.3, the nanotube probe was found unacceptable, while W/d=0.5 and 0.8 respectively produced ◯ and ⊚ ratings, revealing that L/d=0.5 or more was found to be acceptable. In other words, in order that said partial coating film provides minimum required fastening strength for a probe needle, L/d≧0.5 must be satisfied. Furthermore, L/d≧0.8 produces a desirable fastening strength, and L/d≧1 would be still more desirable. In (5C), various average thickness of coating film was evaluated. In the case of T=1 nm, the nanotube probe was found unacceptable, while T=2 nm, 3 nm and 4 nm respectively produced Δ, ◯ and ⊚ ratings. In other words, in order that said partial fastening strength for a probe needle, said average coating film thickness T must be 2 nm or more. Furthermore, T≧3 nm would produce a desirable fastening strength, and T≧4 nm would be still more desirable. FIG. 6 shows similar ratings of fastening strength of the nanotubes 8 on the etched cantilever. It is expected that an etching treatment on the protruded portion of the cantilever would improve the firmness of fastening, due to reformation of the surface of the protruded portion. Here, there are many types of etching treatment, including chemical etching using hydrofluoric acid or phosphoric acid, electrolytic etching, plasma etching and laser beam etching. Out of these, a proper etching method can be selected in accordance with the purposes. Like in FIG. 5, ratings of fastening strength with etching are summarized on the basis of W/d, L/d and T. As shown in (6A), even with W/d value of 0.1, the minimum required fastening strength was obtained for actual service. W/d≧0.3 produced more desirable rating, and W/d≧0.5 showed excellent rating. As shown in (6B) the minimum required strength was obtained with L/d≧0.3, while L/d≧0.5 and L/d≧0.8 produced, respectively, more desirable and excellent ratings. As shown in (6C) as far as the average coating thickness T is concerned, T≧1 nm was found to be the minimum required coating thickness, while T ≧2 and T≧3 generated desirable and excellent ratings. Thus it has been verified that the fastening strength can be improved by etching to an extent corresponding to one level in said rating. Such improvement is considered to be attributable to reformation of the surface of the protruded portion of the cantilever that allows increased strength of binding with the nanotube. Taking account of etching treatment, necessary fastening strength has been found available, if W/d≧0.1, L/d≧0.3 and T≧1 nm are satisfied. Without etching, W/d≧0.3, L/d≧0.5 and T≧2 nm would be required to obtain necessary fastening strength. FIG. 7 is a process diagram showing a method for fixing a nanotube 8 on a protruded portion 4 of cantilever formed with curve. First a nanotube adhered on the nanotube cartridge 6 is located close to the curvedly formed surface 22 of the protruded portion 4. the first partial coating film 12a is then formed by irradiating an electron beam 10 at the first fastening position P1 where said nanotube 8 comes in contact with said curved surface 22 of protruded portion. Then, the nanotube 8 is tilted so as to have it contact the curved surface at the second fastening position P2 in the vicinity of the tip end 7 of the protruded portion. By irradiation of the electron beam 10 at said position P2, the second partial coating film 12b is formed. As the result, the nanotube 8 is fastened to said curved surface 22 at least two positions in contact, and while so doing, the prescribed fastening strength is maintained by satisfying said coating conditions. In the meantime, furthermore, as the clearance 23 existing between the nanotube 8 and the curved surface 22 is left uncoated, the overall coating time is reduced and efficient coating operation is made available. FIG. 8 is an explanatory diagram of a method for fastening a nanotube 8 on a non-curved protruded portion 4. The protruded portion 4 of the cantilever is formed to have a straight, instead of curved, surfaces 5a and 5b. The first coating film 12a and the second coating film 12b are formed on either 5a or 5b of the surface to fasten the nanotube 8. In (8A), the cantilever portion 3 is oriented in Z-axis with its protruded portion oriented in Y-axis while the nanotube 8 is fastened on the surface 5a. In (8B), the nanotube 8 is fastened on the surface 5b of the protruded portion 4 of the cantilever. Thus, the nanotube 8 can be fastened to either the surface 5a or the surface 5b of the protruded portion 4 of the cantilever. By freely controlling the attitude of the nanotube cartridge 6 relative to the protruded portion 4, the surface to which the nanotube is fastened can be selected freely. FIG. 9 is a process diagram showing the procedures for having the nanotube 8 pass through the vicinity of the tip end 7 of the protruded portion 4. If the nanotube 8 deviates from the tip end 7, it is liable to happen that both the nanotube tip end 8c and the tip end 7 of the protruded portion 4 simultaneously function as probe needle, that can result in such deterioration of the image as image overlapping (double exposure). In order to ensure visible image, it is necessary to prevent the tip end 7 of the protruded portion 4 from function as a probe needle. For this purpose, locating the nanotube 8 to pass through a vicinity of the tip end 7 of protruded portion is effective. In (9A), the nanotube 8 is adhered to the nanotube cartridge 6 not perpendicularly but obliquely. The nanotube cartridge 6 is a source of supply of nanotube 8, but nanotubes 8 are usually arranged obliquely relative to the edge of the nanotube cartridge 6. The nanotube 8 adhere to the nanotube cartridge 6 in an adhering area 6A, wherein such adhesion takes place due to the intermolecular attraction. As the method for effecting such adhesion is out of the scope of this invention, it is not discussed here. In (9B), a nanotube 8 arranged obliquely on the nanotube cartridge 6 is first set in contact with the protruded portion 4, and then the first fastening position P1 in the contact area are subjected to the irradiation of electron beam to form the first coating film 12a. Next, the nanotube 8 is forcibly made to pass the tip end 7 of the protruded portion. There are two methods to do this. The first method is to move the nanotube cartridge 6 in the arrow e direction, so as to allow the nanotube 8 to tilt counterclockwise around the first fastening position P1 as a fulcrum. The second method is to move the protruded portion 4 in the arrow f direction and thereby allow the nanotube 8 to tilt counterclockwise around the adhering area 6a as the fulcrum. In either of these methods, the position of nanotube 8 is corrected so as to pass through the tip end of the protruded portion. In (9C), the second coating film 12b is formed by irradiation of electron beam 10 on the second fastening position P2 adjacent the tip end 7. Thus, the nanotube 8 is fastened to the protruded portion 4 by the first partial coating film 12a and the second partial coating film 12b in such way that it passes through the vicinity of the tip end 7. Here, the vicinity of the tip end 7 implies the position of the tip end 7 and some area adjacent the tip end 7. It goes without saying that it is optimum to have the nanotube 8 pass directly through the tip end 7. FIG. 10 is a process diagram illustrating a method for forming a third partial coating film 12c on an intermediate position of the nanotube 8. In (10A) and (10B), the same operation as described in FIG. 9 is conducted to fasten the nanotube 8 to the protruded portion 4 by means of the first partial coating film 12a and the second partial coating film 12b. In addition, in order to increase the fastening strength, a third partial coating film 12c is formed by irradiating electron beam 10 in the intermediate area between the first partial coating film 12a and the second coating film 12b. If necessary, further addition of fourth or more partial coating films can be introduced to constitute a multi-point fastening that would ensure further firmness of the fastening. FIG. 11 is a process diagram showing a method for fastening a nanotube 8 on the protruded portion 4 of the cantilever of which surface is curved concavedly. The protruded portion has a surface curved concavedly up to the sharp tip end 7, forming a curved surface 22. The process for fastening a nanotube 8 on the curved surface 22 is described in (11A), (11B) and (11C). First in (11A), the first partial coating film 12a is formed by irradiating electron beam 10 on the first fastening position P1 located in the lower area of the nanotube 8. Then in (11B), the nanotube cartridge 6 is moved in the direction of arrow g, and at the same time, moved minutely in the direction of the arrow h to cause the nanotube to have full line contact with the curbed surface while adjusting the nanotube 8 around the first partial coating film 12a as the fulcrum so as to pass through the sharp tip end 7. In (11C), the electron beam 10 is irradiated on an upper position of the nanotube 8 that has been kept in full line contact with the protruded portion 4 of the cantilever to form the second partial coating film 12b. Since such full line contact between the nanotube 8 and the protruded portion 4 of the cantilever increases the Van der Waals force between them, it further increases the fastening strength. Furthermore, the nanotube fastened in such way has its tip end portion oriented upward almost perpendicular to the cantilever. In consequence, as the nanotube faces virtually perpendicular to the sample surface, the nanotube probe, placed perpendicular to the indentations and projections of the sample surface, can pick up these changes of sample surface accurately, and rapid reduction of erroneous information can be expected. FIG. 12 is a process diagram showing a method for fastening the nanotube 8 on a concavedly curved surface of the protruded portion 4 of cantilever by three fastening points. In (12A) and (12B), the same operation as described in FIG. 11 is conducted to fasten the nanotube 8 on the curved surface 22 by two-point fastening, or the first partial coating film 12a and the second partial coating film 12b, wherein the nanotube 8 is so fixed that it passes through the sharp tip end 7. In (12C), in order to increase the fastening strength, a third partial coating film 12c is formed by irradiation of electron beam in the intermediate area. This third partial coating film 12c is effective to make the bondage between the nanotube 8 and the curved surface 22 firmer. If necessary, a further addition of fourth or more partial coating film can be introduced to constitute a multi-point fastening that would ensure further firmness of the fastening. FIG. 13 is a process diagram showing a method for fastening the nanotube 8 on a convexedly curved protruded portion 4 of cantilever. In (13A), when the curved surface 22 of a protruded portion 4 of a cantilever is convexedly curved up to the sharp tip end, the first partial coating film 12a is formed by irradiation of electron beam 10 at a lower position of the nanotube 8. Then in (13B), while the nanotube 8 is caused to contact the vicinity of the sharp tip end 7, the second partial coating film 12b is formed in said contact area by irradiation of electron beam. Thus, this partial coating film approach facilitates fastening of a nanotube on the holder surface that has a variety of shapes. FIG. 14 is an explanatory diagram showing the method for fastening one nanotube 8 out of a group of nanotubes 36. From the group of several to several tens of nanotubes placed on the nanotube cartridge 6, an appropriate nanotube is selected as the probe needle. This nanotube only is then fastened to the protruded portion 4 of cantilever by irradiating electron beam having a minute beam diameter. In other words, as long as the partial coating films 12a and 12b are kept smaller than the clearance between the neighboring nanotubes adhered to the nanotube cartridge 6, a single nanotube can be fastened, and thereafter the nanotube cartridge 6 can be retired in the direction of the arrow j, or instead the protruded portion 4 of the cantilever may be retired in the direction of the arrow k, so that the selected nanotube 8 only can be removed. In this way, by picking up nanotube 8 one by one from a single nanotube cartridge 6, a plenty of nanotube probe can be manufactured. Therefore, this method enables to improve remarkably the production efficiency for nanotube probes. In the above-described example, an electron microscope is used as the view-magnifying device, and an electron beam for forming the partial coating films. However, other view magnifying devices and charged beam can be used in accordance with the purposes. For instance, a focusing ion beam device can be employed to use ion beam as the charged beam. According to the first mode of the present invention, wherein a nanotube is fastened to a holder surface with partial coating films, a substantial reduction of fastening time is made possible so that both the mass-production and reduction of production cost can be accomplished. Furthermore, by reducing the size of the partial coating film, the same nanotube cartridge can be used repeatedly, so as to improve production efficiency for nanotube probes. According to the second through the fourth modes, the size requirement for the partial coating film are defined as W/d≧0.1, L/≧0.3 and T≧1 (nm), where W represents the maximum coating skirt width, d represents the nanotube diameter, L represents the coating length and T represent the average coating thickness. Since the energy flow density, irradiation time and scanning range (beam oscillation width) of the charged beam can be initially set so that these conditions can be satisfied, it is possible to manufacture the nanotube probes without skilled operators. Thus, significant improvement of productivity is possible. According to the fifth mode, since a nanotube can be manufactured by simply fastening a nanotube with the use of partial coating films on the cantilever used conventionally, it is possible to achieve significant cost reduction. According to the sixth mode, the partial coating films can be used to fasten a nanotube on a curved surface of protruded portion of the cantilever by applying partial coating films at contact points only. Even in case the contact area between the nanotube and said curved surface is small, the partial coating film on the contact area can achieve as strong fastening as the overall coating film. This does not only enable to cut down on the production time, but also facilitate the use of conventional cantilever to a great extent, ensuring attainment of labor saving. According to the seventh mode, the possibility of the sharp tip end of the protruded portion functioning as a probe needle is eliminated by having the nanotube pass through the vicinity of the sharp end of the protruded portion, so that a highly accurate surface image can be obtained by only the nanotube probe. Thus, reliability of the nanotube probe can be drastically improved. To be more specific, elimination of double exposure ensures correct detection of nanostructure of substance sample or organic sample, providing an epoch-making measuring device for nanotechnology. The eighth mode of the present invention enables to shorten the production time of nanotube probe, and makes it feasible to realize mass-production and cost reduction. According to the ninth mode of the present invention, the possibility of the sharp tip end of the protruded portion functioning as a probe needle is eliminated by having the nanotube pass through the vicinity of the sharp end of the protruded portion, so that a highly accurate surface image can be obtained by only the nanotube probe. Thus, reliability of the nanotube probe can be drastically improved. To be more specific, elimination of double exposure ensures correct detection of nanostructure of substance sample or organic sample, providing an epoch-making measuring device for nanotechnology. The tenth mode of the present invention allows nanotube probe to be made by fastening a nanotube on a curved surface with the partial coating films. As this enables to construct nanotube probes using holders of arbitrary shapes, diversification of nanotube probe is expected. According to the eleventh mode, since the nanotube is fastened to the curved surface of the protruded portion of the cantilever in a state of close line-contact, the fastening strength by the partial coating films can be augmented by the Van der Waals force between the contacting surfaces, so that more durable nanotube probe can be provided. Furthermore, since the nanotube probe needle in this mode is made to be perpendicular to the sample surface, it can detect the indentations and projections on the sample surface accurately. According to the twelfth mode, fastening strength of the nanotube is further increased by three partial coating films on the base end portion of the nanotube. According to the thirteenth mode, the fastening operation is conducted in direct observation under an electron microscope, so that the partial coating film can be formed at high precision. In addition to the formation of coating films, other tasks, like processing of nanotube and addition of functional substances, can be conducted precisely in the electron microscope. According to the fourteenth mode, coating film can be formed by the use of electron beam or ion beam. Since it is possible to manufacture nanotube probe utilizing the existing electron microscope and focusing ion beam apparatus (FIB apparatus), no new charged beam generator is required. As the electromagnetic control has been developed for electron beam and ion beam, high precision microscopic processing is made possible. According to the fifteenth mode, merely by regulating the scanning range of the electron beam or ion beam, the average thickness, coating length, and maximum coating skirt width can be changed freely. Consequently, nanotube probes can be manufactured using arbitrarily designed holders with desired fastening strength. Furthermore, as the beam can be narrowed down to the minimum, deposit of impurities on the holder due to the charged beam can be minimized. The nanotube probes according to the present invention is applicable to ordinary scanning probe microscope. Scanning probe microscopes include scanning tunnel microscopes (STM) which detect a tunnel current, atomic force microscopes (AFM) which detect surface indentations and projections using the Van der Waals force, leveling force microscopes (LFM) which detect surface differences by means of frictional force, magnetic force microscopes (MFM) which detect magnetic interactions between a magnetic probe needle and magnetic field regions on the sample surface, electric field force microscopes (EFM) which apply a voltage across the sample and probe needle, and detect the electric field force gradient, and chemical force microscopes (CFM) which image the surface distribution of chemical functional groups, etc. What these microscopes have in common is that they all detect characteristic physical or chemical actions by means of a probe needle, and thus attempt to detect surface information with a high resolution at the atomic level. Therefore, the use of nanotube probes according to the present invention will help improve resolving power and measuring accuracy to a drastic extent.
046648798	abstract	A guide tube flow restrictor for use on an upper guide tube housing support plate of a nuclear reactor, for guiding of a control rod drive shaft through an aperture in the support plate and restriction of flow of coolant therethrough, has an outer ring seatable on the support plate, the outer ring having a flange member from which there depends a plurality of flexible members, the flexible members having inwardly disposed deflectors thereon, and extending through the bore of the outer ring and the aperture of the support plate. An axially insertable sleeve, upon insertion into the outer ring, between the flexible members, contacts the deflectors thereon to radially force the flexible members outwardly to secure the same with the walls of the aperture of the support plate. Baffles are provided on the flexible segments and additional locking members provided between the outer ring and inner sleeve. Shoulders on the outer ring prevent the accumulation of deposits or corrosive affects which could render difficult the disengagement of the outer ring and inner sleeve for replacement thereof.
	summary
	claims	1. An apparatus for controlling a neutron beam, comprising a plurality of columnar prisms that are made of a material having a refractive index of less than 1 for a neutron beam, and are arranged so as to be multi-layered. 2. An apparatus for controlling a neutron beam according to claim 1, wherein the columnar prisms 1 each have an approximately right-triangle-shaped section, and are three-dimensionally multi-layered such that respective surfaces of the columnar prisms are in parallel to one another. 3. An apparatus for controlling a neutron beam according to claim 2, wherein oblique surfaces of the multi-layered columnar prisms are in parallel to one another, and face in the same direction so as to approximately form a triangular prism as a whole. 4. An apparatus for controlling a neutron beam according to claim 3, comprising a plurality of said triangular prisms arranged such that oblique surfaces respectively constituting the triangular prism cross each other. 5. An apparatus for controlling a neutron beam according to claim 1, wherein the columnar prisms 1 each have an approximately right-triangle-shaped section,the apparatus for controlling the neutron beam comprises a plurality of horizontal prism plates each of which includes the columnar prisms horizontally arranged such that respective surfaces of the columnar prisms are in parallel to one another, andthe plurality of horizontal prism plates are vertically multi-layered so as to be horizontally turned alternately by 90 degrees. 6. An apparatus for controlling a neutron beam according to claim 1, comprising a positioning member that sets the plurality of columnar prisms at predetermined positions, respectively. 7. A method for manufacturing a neutron beam controlling apparatus, comprising:forming a plurality of columnar prisms that are made of a material having a refractive index of less than 1 for a neutron beam, and each have an approximately right-triangle-shaped section; andthree-dimensionally multi-layering the plurality of columnar prisms such that respective surfaces of the columnar prisms are in parallel to one another. 8. A method for manufacturing a neutron beam controlling apparatus according to claim 7, wherein the forming of the plurality of columnar prisms is performed by any of molding, extruding, cutting, grinding, whetting or any combination thereof. 9. A method for manufacturing a neutron beam controlling apparatus according to claim 7, wherein forming the plurality of prisms comprising:making stick-shaped members of said material;setting the stick-shaped members in a plurality of grooves formed on a jig, the grooves having the same shape; andflattening upper surfaces of the grooves at the same time. 10. A method for manufacturing a neutron beam controlling apparatus according to claim 9, wherein the flattening of the upper surfaces of the grooves is performed by ELID grinding. 11. A method for manufacturing a neutron beam controlling apparatus according to claim 9, wherein the flattening of the upper surfaces of the grooves is performed by a straight grinding wheel, a cup grinding wheel or a lap.
	claims	1. A transportable container for nuclear fuel, comprising: an outer container bounding an interior and defining an overall volume; a thermal insulation material disposed within the interior bounded by the outer container, the thermal insulation material bounding an internal cavity; a neutron absorbing material received within the internal cavity; and a plurality of laterally spaced apart fuel containers received within the internal cavity, each fuel container having an internal volume adapted to receive unspent nuclear fuel, wherein the sum of the internal volumes of the fuel containers is at least 5% of the overall volume defined by the outer container. 2. A container according to claim 1 in which the internal cavity is divided up into a series of chambers, the chambers being defined by one or more elements, the elements spanning substantially the full height of the internal cavity and wherein the fuel containers are provided in more than three of the chambers. claim 1 3. A container according to claim 2 in which the internal cavity is divided into nine chambers, three chambers by three chambers, the fuel containers being provided in at least four of the chambers and the neutron absorbing material being provided in at least one of the chambers. claim 2 4. A container according to claim 2 in which the cavity is provided with nine sleeve elements, in a three by three sleeve element arrangement, to define nine chambers, the fuel containers being provided in at least four of the chambers, the neutron absorbing material being provided in at least one of the chambers. claim 2 5. A container according to claim 1 in which the internal cavity is provided with a correspondingly shaped single unit internal container comprising four side walls and a base. claim 1 6. A container according to claim 5 in which the internal container is divided up into a series of chambers. claim 5 7. A container according to claim 6 in which the internal container is divided by one or more elements crossing the internal cavity or container. claim 6 8. A container according to claim 6 in which the internal container is divided by one or more sleeves. claim 6 9. A container according to claim 8 in which the sleeves are encased in the neutron absorbing material. claim 8 10. A container according to claim 9 in which the neutron absorbing material comprises a resin-based material. claim 9 11. A container according to claim 10 , wherein the resin is introduced around the sleeves as a liquid during manufacture. claim 10 12. A container according to claim 5 in which the internal container is made of steel. claim 5 13. A container according to claim 12 wherein the steel comprises at least one of boronated steel or stainless steel. claim 12 14. A container according to claim 1 in which the insulation material is provided in a series of discrete layers with one or more base layers and/or one or more wall layers for each wall. claim 1 15. A container according to claim 1 in which the insulation material is also neutron absorbing. claim 1 16. A container according to claim 1 in which the internal cavity is divided up into nine chambers or sleeves of substantially equivalent size. claim 1 17. A container according to claim 16 in which the fuel containers comprise cylindrical drums received in one or more of the chambers or sleeves. claim 16 18. A container according to claim 16 in which the fuel containers are provided in more than three of the chambers or sleeves. claim 16 19. A container according to claim 16 in which at least one of the chambers or sleeves is provided with the neutron absorbing material. claim 16 20. A method of transporting and/or storing nuclear fuel comprising placing nuclear fuel in a container according to claim 1 . claim 1 21. A container according to claim 1 in which the sum of the internal volumes of the fuel containers is at least 10% of the overall volume defined by the outer container. claim 1 22. A container according to claim 1 in which the sum of the internal volumes of the fuel containers is at least 15% of the overall volume defined by the outer container. claim 1 23. A container according to claim 1 in which the sum of the internal volumes of the fuel containers is approximately 20%-40% of the overall volume defined by the outer container. claim 1 24. A container according to claim 1 further comprising a lid releasably attached to the outer container. claim 1 25. A container according to claim 24 in which the lid comprises thermal insulation material. claim 24 26. A container for transporting nuclear fuel, comprising: an outer container defining a cavity therein; a plurality of laterally spaced apart tubular sleeves disposed within the cavity, each of the plurality of sleeves being adapted to receive a nuclear fuel container containing unspent nuclear fuel; a nuclear fuel container disposed within at least one of the plurality of laterally spaced apart tubular sleeves, the nuclear fuel container being adapted to receive unspent nuclear fuel; and a polymeric material disposed Within the cavity so as to individually surround each of the plurality of sleeves within the cavity; and a neutron absorbing material disposed within the cavity. 27. A container according to claim 26 in which the polymeric material is a resin that is introduced into the cavity as a liquid during manufacture. claim 26 28. A container according to claim 26 in which the polymeric material is an insulating material. claim 26 29. A container according to claim 26 in which at least 50% of the cavity is filled with the polymeric material. claim 26 30. A container according to claim 26 further comprising a layer of an insulation material disposed between the polymeric material and the outer container, the insulation material having material properties different than the polymeric material. claim 26 31. A container according to claim 30 in which the insulation material comprises calcium silicate. claim 30 32. A container according to claim 30 in which the insulation material is provided in a series of discrete layers with one or more base layers and/or one or more wall layers for each wall. claim 30 33. A container according to claim 30 , further comprising an inner container disposed within the cavity between the layer of insulation material and the polymeric material. claim 30 34. A container according to claim 30 , in which the insulation material is neutron absorbing. claim 30 35. A container according to claim 26 in which the plurality of sleeves are ordered in a 3xc3x973 array. claim 26 36. A transportable container for uranium oxide, comprising: an outer container formed of steel bounding an interior and defining an overall volume; a lid releasably fastenable to the outer container; a thermal insulation material disposed within the interior bounded by the outer container, the thermal insulation material bounding an internal cavity; four or more laterally spaced apart sleeves disposed within the internal cavity; a neutron absorbing or moderating material at least partially surrounding each sleeve; and a fuel container received within each sleeve, the fuel container provided with a releasable lid and defining an internal volume adapted to receive unspent uranium oxide, the sum of the internal volumes of the fuel containers being at least 5% of the overall volume defined by the outer container. 37. A container for transporting nuclear fuel, the container comprising: an outer container defining an interior chamber therein; a neutron absorbing material disposed within the interior chamber; a plurality of laterally spaced apart sleeve members disposed within the interior chamber, each of the plurality of sleeve members being configured to receive therein a container of unspent nuclear fuel; and a nuclear fuel container comprising polyethylene received within at least one of the sleeve members, the nuclear fuel container adapted to contain unspent nuclear fuel. 38. A container according to claim 37 in which the polyethylene is a neutron absorber in a steel container corresponding to the size and shape of the sleeve into which the steel container is received. claim 37 39. A container according to claim 37 in which the polyethylene comprises at least one polyethylene bag. claim 37
	summary
	description	The present invention relates to a storage canister that seals stored nuclear fuel as radioactive waste and is installed in a nuclear waste storage facility, and a method to prevent stress corrosion cracking of the storage canister. Nuclear fuel as radioactive waste is stored in a storage canister in a nuclear facility of a nuclear power plant and so on. The nuclear fuel is transported from the storage canister to a nuclear waste storage facility 100 in FIG. 1 so as to be stored for an extended period. In the storage facility 100, a cask 101 contains a storage canister 102. There is a concern that the metallic storage canister 102 may have stress corrosion cracking. The storage canister 102 may have stress corrosion cracking if a tensile stress remains on an austenitic stainless steel material constituting the storage canister 102 in a corrosive environment of sea salt or the like. As shown in FIG. 1, vent holes 101a and 101b are formed at the top and bottom of the cask 101 so as to dissipate heat, which is generated by the nuclear fuel, from the surface of the storage canister 102. Since the outside air is passed through the vent holes 101a and 101b, the storage canister 102 is kept exposed to the outside air. In Japan, the nuclear waste storage facility 100 is built in a coastal region and thus cannot avoid a corrosive environment of sea salt and so on. A tensile stress remaining on the storage canister 102 is a tensile residual stress that occurs when a cover is welded to a body constituting the storage canister 102. In a known technique, stress corrosion cracking is prevented by performing plastic working after welding so as to eliminate a tensile stress remaining on the storage canister 102 and generate a compressive residual stress (See Non Patent Literature 1). In this technique, for example, the cover is welded to the body of the storage canister 102 and then an operation is performed to apply a compressive stress to and near a welded part. More specifically, nuclear fuel is supplied into the body of the storage canister 102 in a nuclear power plant, a primary cover is welded, and then a secondary cover is welded to seal the nuclear fuel. A tensile residual stress is generated by welding on the top and covers of the body of the storage canister 102 that contains the nuclear fuel. The welded part undergoes plastic working in which a compressive stress is applied by, for example, peening. This eliminates the tensile residual stress and leaves the compressive stress over the outer surface of the storage canister 102. In domestic storage of nuclear fuel, the state of the storage canister 102 is a required condition for preventing stress corrosion cracking. The sealed storage canister 102 that contains nuclear fuel does not leak a radioactive material to the outside but allows external leakage of radiation through the thin body of the storage canister 102. In order to prevent stress corrosion cracking of the storage canister 102, plastic working needs to be performed so as to face the storage canister 102, leading to an adverse effect of radiation leaking from the storage canister 102. Non Patent Literature 1: Study on interim storage of spent nuclear fuel by concrete cask for practical use, Research Report N10035, issued and reported by the Central Research Institute of Electric Power Industry in May 2011 The storage canister 102 containing nuclear fuel is transported to a nuclear storage facility while being placed in a thick transport cask. In order to suppress the influence of radiation, the storage canister 102 is placed into the transport cask in a pool, and then plastic working for preventing stress corrosion cracking is performed using a space near the upper opening of the storage canister 102. Welding on the cover generates a residual tensile stress over a relatively deep range from the upper end to the bottom of the body. This requires work to a deep position from the upper opening. For example, if the top of the transport cask is further opened, an amount of exposure may disadvantageously increase. In view of the problem of the related art, an object of the present invention is to provide a method to prevent stress corrosion cracking of a storage canister and the storage canister so as to generate a compressive residual stress over the outer surface of the storage canister while blocking radiation from nuclear fuel. In order to generate a compressive residual stress over the outer surface of a storage canister while suppressing the influence of radiation, the inventors have focused on the significance of work with a small upper opening between the storage canister and a transport cask and reached the following technical solution: A method to prevent stress corrosion cracking of a storage canister according to the present invention is a method to prevent stress corrosion cracking of a storage canister by applying a compressive stress to a range where a tensile residual stress is generated on a metallic cylindrical body by welding a cover to the top of the cylindrical body, the method including: applying a first compressive stress beforehand to the range of the cylindrical body where the tensile residual stress is expected to be generated by the welding of the cover; canceling the tensile residual stress generated by the welding of the cover, with a compressive residual stress generated in the range; and then applying a second compressive stress so as to generate a compressive residual stress over the range. According to the present invention, the first compressive stress is applied beforehand to the range of the body where the tensile residual stress is expected to be generated by the welding of the cover. This cancels the tensile residual stress generated by the welding and reduces a work range of application of the second compressive stress, accordingly. Thus, work can be performed with a small upper opening between the storage canister and a transport cask, thereby generating a compressive residual stress over the outer surface of the cylindrical body. The range of the cylindrical body that receives the first compressive stress is an axial range extending inward from the upper end of the cylindrical body in the axial direction, the axial range L satisfying the relational expression below:L≧2.5√{square root over (rt)} (r: the external radius of the cylindrical body, t: the thickness of the cylindrical body). The axial range of the cylindrical body where a tensile residual stress is generated by welding of the cover is indicated by the right side of the relational expression. Thus, if the axial range for applying the first compressive stress satisfies the expression, a compressive residual stress can be generated over the outer surface of the cylindrical body. The first compressive stress can be applied by various working methods. For example, zirconia shot peening or burnishing is preferably used. A storage canister according to the present invention is a storage canister including a metallic cylindrical body with a cover welded to the top of the cylindrical body, the storage canister being installed in a cask while containing nuclear fuel in a sealing state, wherein a first compressive stress is applied beforehand to a range of the cylindrical body where a tensile residual stress is expected to be generated by the welding of the cover, the tensile residual stress generated by the welding of the cover is canceled with a compressive residual stress generated in the range, and then a second compressive stress is applied so as to generate a compressive residual stress over the range. According to the present invention, the first compressive stress is applied beforehand to the range of the cylindrical body where a tensile residual stress is expected to be generated by welding the cover. This cancels the tensile residual stress generated by welding and reduces the work range of application of the second compressive stress, enabling work with a small upper opening between the storage canister and the transport cask and generation of a compressive residual stress over the outer surface of the cylindrical body. The storage canister may enable work for applying the second compressive stress to an upper opening between the cask and the cylindrical body. Specifically, if the cover includes an upper cover welded to the upper end of the cylindrical body and a lower cover welded to the cylindrical body inside the upper cover, the lower cover may be welded at a position in an axial range from the upper end of the cylindrical body to an L minimum value indicated by the right side of the relational expression. As has been discussed, according to the present invention, a tensile residual stress generated by welding is canceled. This reduces a work range for applying a second compressive stress, enabling work with a small upper opening between a storage canister and a transport cask. Thus, a compressive residual stress can be generated over the outer surface of a cylindrical body while radiation from nuclear fuel is blocked. An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 2 is a side view of a storage canister 1 according to the embodiment of the present invention. The storage canister 1 stores spent nuclear fuel 50. The stored spent nuclear fuel 50 is installed in a nuclear storage facility. The storage canister 1 is made of austenitic stainless steel and includes a long cylindrical body 2 (cylindrical body), a bottom member 3 that closes the bottom of the body 2, and a cover 4 that closes a top 2a of the body 2. The bottom member 3 and the cover 4 are welded to the body 2, sealing the storage canister 1 so as to prevent leakage of a radioactive material. Generally, the body 2 of the storage canister 1 is about 1700 mm in outside diameter, about 4600 mm in height, and about 13 mm in thickness. The cover 4 of the present embodiment includes an inner primary cover member 5 (lower cover) and an outer secondary cover member 6 (upper cover). The number of cover members constituting the cover that seals the body 2 is not limited and thus one or at least three cover members may be used. The edge of the primary cover member 5 and an inner surface 2b of the body 2 are welded to each other; meanwhile, the edge of the secondary cover member 6 and the inner surface 2b of the body 2 are welded to each other. The bottom member 3 is welded to a lower end 2c of the body 2. FIG. 3 is a flowchart for explaining the steps of a method to prevent stress corrosion cracking of the storage canister 1. In the method to prevent stress corrosion cracking of the storage canister according to the present embodiment (hereinafter, will be referred to as a method to prevent stress corrosion cracking), stress corrosion cracking is prevented by a residual compressive stress. A first compressive stress is applied beforehand to an axial range of the body 2 where a tensile residual stress is expected to be generated by welding of the cover 4, the cover 4 is welded with the compressive stress in the axial range so as to cancel the tensile residual stress, and then a second compressive stress is applied. Specifically, the first compressive stress is applied to the body 2, spent nuclear fuel is accommodated in the closed-end body 2 installed in a transport cask in a pool, and then the cover 4 is automatically welded to the body 2 to seal the body 2. In this state, the second compressive stress is applied to the top of the body 2. After that, the transport cask is transported with the storage canister 1 to a nuclear storage facility so as to store the spent nuclear fuel. The steps will be sequentially described below. First, the bottom member 3 is welded to the cylindrical body 2 to form a closed-end cylindrical body 7 shown in FIG. 4. A tensile residual stress generated by welding remains in a bottom 7a of the closed-end cylindrical body 7. Thus, plastic working is performed using, for example, shot peening to eliminate the tensile residual stress and leave a compressive stress. This can prevent stress corrosion cracking of the bottom 7a. In this working, nuclear fuel is not stored and no structure surrounds the body 2, thereby obtaining a sufficient working space without radiation exposure. FIG. 5 is an enlarged view at and near the welded part of the body 2. Before the cover members 5 and 6 are welded, work for applying the first compressive stress is performed beforehand in the range of the body 2 where a tensile residual stress is expected to be generated by welding. A range L in the top 2a of the body 2 where the first compressive stress is applied is an axial range that is extended inward from an upper end 2d of the body 2 in the axial direction. The range L satisfies a relational expression shown below. Thus, the axial range L where the first compressive stress is applied needs to extend from the upper end 2d of the body 2 at least to a minimum value of L (hereinafter, will be referred to as an L minimum value) which is expressed by the right side of the relational expression. The L minimum value is about 300 mm in the typical storage canister 1.L≧2.5√{square root over (rt)} (r: the external radius of the cylindrical body, t: the thickness of the cylindrical body) FIG. 6(a) is an explanatory drawing of the concept of the method to prevent stress corrosion cracking according to the present invention. FIG. 6(b) is an explanatory drawing of the related art corresponding to the present invention. The axial range of a tensile residual stress generated by welding of the secondary cover member 6 extends from the upper end 2d of the body 2 to the L minimum value. Thus, the first compressive stress is applied beforehand at least to the range to generate a compressive residual stress, thereby canceling the tensile residual stress generated during welding. Since the upper end 2d of the body 2 and a range s1 near the upper end 2d are substantially melted during welding, the applied compressive residual stress is also eliminated only in the axial range s1. Hence, in the step of applying the second compressive stress, a compressive residual stress can be generated over the outer surface of the body 2 only by processing the narrow axial range s1. This can apply the second compressive stress at a smaller depth (axial range s1) than a conventional depth s2. Moreover, a compressive residual stress may be applied beforehand by some method to a part other than the L range where the first compressive stress is not applied. In the present embodiment, the inner primary cover member 5 is welded to the body 2, and then the outer secondary cover member 6 is welded to the body 2. Welding of the secondary cover member 6 generates a tensile residual stress in the axial range from the upper end 2d of the body 2 to the L minimum value. Similarly, a tensile residual stress is also generated by welding of the primary cover member 5. The primary cover member 5 only needs to be welded at a position in the axial range from the upper end 2d of the body 2 to the L minimum value. The outer end of the axial range L where the first compressive stress is applied is the upper end 2d of the body 2. This configuration cancels the tensile residual stress generated by welding of the primary and secondary cover members 5 and 6. As has been discussed, a tensile residual stress is generated in the range from the upper end 2d of the body 2 to the L minimum value and thus a first compressive stress P1 needs to be applied to this range. The axial range L where the first compressive stress P1 is applied may be extended from the upper end 2d to the lower end 2c of the body 2 or to an axial central part 2e. The axial range L is preferably extended to the L minimum value+about 100 mm inward or more preferably to the L minimum value+about 50 mm inward in view of working. Plastic working for applying the first compressive stress P1 is performed up to the L minimum value+about 100 mm, thereby more reliably canceling the tensile residual stress generated by welding. A tensile residual stress is also generated on the cover members 5 and 6 by welding. The outer secondary cover member 6 is unfortunately exposed to the outside air. The secondary cover member 6 may also similarly undergo plastic working for applying the first compressive stress. The transport cask with an opened upper end does not interfere with a working space and thus the first compressive stress does not always need to be applied to the cover 4. A welding method for the body 2 and the cover 4 is preferably, but not exclusively, laser welding or arc welding. FIG. 7 is a graph showing an axial residual stress on the outer surface of the body during welding of the welding method. The region of a tensile residual stress is larger in arc welding than in laser welding, proving that laser welding is more preferable. Plastic working for applying the first compressive stress and the second compressive stress will be described below. A compressive residual stress already generated on an austenitic stainless steel material by scaling has a maximum depth of about 200 μm, requiring plastic working for applying the first compressive stress and the second compressive stress. For example, plastic working for applying a compressive stress includes, but not exclusively, peening methods such as laser peening, water jet peening, and shot peening. Laser peening and water jet peening with low workability and high construction cost are not generally used. Known shot peening methods include, for example, cast steel shot, alumina shot, and zirconia shot. In cast steel shot, there is a concern that a compressed layer having a depth of, for example, about 0.4 mm may cause red rust. In alumina shot, a rough surface is not disadvantageous but a compressed layer is about 0.5 mm in depth, generating a compressive residual stress at a relatively small depth as in cast steel shot. In zirconia shot, zirconia has high toughness and a compressed layer is about 0.7 mm in depth, thereby generating a compressive residual stress at a larger depth. In the present embodiment, zirconia shot is used to emit zirconia particles having a diameter of 1.0 μm with an air pressure of 5 kg/cm2G and a coverage of 3. The compressed layer has a depth of 0.7 mm. In the three shot patterns, zirconia shot is the most suitable. Burnishing is another known plastic working method for applying a compressive stress. Burnishing is plastic working in which a pressing tool with a hard spherical member attached to one end of the tool is rolled in contact with the surface of a target material. This method can obtain a deep compressed layer without generating dust and thus is the most suitable for working in a nuclear power generation facility. In various peening methods, a processed surface has a satin finish, whereas in burnishing, a processed surface has a mirror finish. Thus, any one of these methods allows simple visual confirmation of a worked range, achieving higher workability. FIG. 8 is an explanatory drawing showing a change of a residual stress value when a tensile stress is applied to the compressive stress processing part of an austenitic stainless steel material. Peening of zirconia shot was performed on one surface 30a of an austenitic stainless steel material 30 having predetermined dimensions. A tensile load was then laterally applied to the surface; meanwhile, a change of a residual stress value of a peening portion 31 was measured. FIG. 8 is a graph of measurement results. A vertical chain line in the graph indicates 243 MPa with a proof stress of 0.2%. The peening portion 31 has a residual stress value of “compression” up to a proof stress of 0.2%. Thus, even in the application of a tensile load, the peening portion 31 has a residual stress on a compression side up to a proof stress of 0.2%. The storage canister 1 designed with one third of the 0.2% proof stress does not eliminate an applied compressive residual stress. Since a nuclear fuel storage facility is built in a coastal region, the storage canister 1 in the cask is always exposed to a salt atmosphere. The existence of a compressive residual stress can prevent stress corrosion cracking but corrosion caused by salt also needs to be taken into consideration. If salt causes corrosion deeper than a compressive residual stress layer, stress corrosion cracking may occur. Thus, a maximum corrosion depth was estimated at a relative humidity of 15% (room temperature) close to a coastal environmental condition. An estimated value was calculated on the assumption that corrosion linearly grows with a maximum corrosion depth of 1000 hours. A total amount of time when stress corrosion cracking is likely to grow is 3853 hours in a northern part of the Honshu island and 15021 hours on a central coast of the Japan Sea according to the temperature of the storage canister and weather data, which is cited from “Study on interim storage of spent nuclear fuel by concrete cask for practical use, Research Report N10035, issued and reported by the Central Research Institute of Electric Power Industry in May 2011 (Non Patent Literature 1)”. The estimated value of the maximum corrosion depth will be shown below. (Grinding) SUS304L: 161 μm (a northern part of the Honshu island), 625 μm (a central coast of the Japan Sea) SUS316L: 213 μm (a northern part of the Honshu island), 829 μm (a central coast of the Japan Sea) (Peening) SUS304L: 114 μm (a northern part of the Honshu island), 442 μm (a central coast of the Japan Sea) SUS316L: 182 μm (a northern part of the Honshu island), 706 μm (a central coast of the Japan Sea) (Burnishing) SUS316L: 215 μm (a northern part of the Honshu island), 838 μm (a central coast of the Japan Sea) A compressive residual stress layer obtained by grinding has a depth of 0, a compressive residual stress layer obtained by peening of zirconia shot has a depth of 800 μm, and a compressive residual stress layer obtained by burnishing has a depth of 1500 μm. Stress corrosion cracking does not appear under the condition of (a corrosion depth<the depth of a compressive residual stress layer). Thus, peening or burnishing is performed to form a compressive residual stress layer of about 1 mm with the application of the first compressive stress and the second compressive stress, preventing stress corrosion cracking caused by the influence of corrosion. Even if a material surface layer is slightly damaged by fretting or collision during the manufacturing of the storage canister 1, the damage has a depth of about several hundreds of μm. Forming the compressive residual stress layer of about 1 mm can prevent stress corrosion cracking caused by the influence of damage. The deeper the compressive residual stress layer, the better. However, the compressive residual stress layer has a maximum depth of about 2 mm or preferably has a depth of about 1 mm in view of workability. The storage canister of the present invention can be obtained by performing the method to prevent stress corrosion cracking. Specifically, the storage canister 1 of the present invention includes the cover 4 welded to the top 2a of the metallic cylindrical body 2 and is installed in the cask while containing nuclear fuel in a sealing state. The first compressive stress is applied beforehand to the range of the body 2 where a tensile residual stress is expected to be generated by welding of the cover 4, the cover 4 is welded with a compressive residual stress in the range so as to cancel the tensile residual stress, and then the second compressive stress is applied so as to generate a compressive residual stress over the range. FIG. 9 is a partial enlarged view of the storage canister 1 contained in a transport cask 10. In order to suppress the influence of radiation, the storage canister 1 is placed into the transport cask 10 and then undergoes plastic working for preventing stress corrosion cracking. Conventionally, plastic working is deeply performed from the top toward the bottom of the body, whereas plastic working on the storage canister 1 of the present embodiment is limited to the small range s1 from the top 2a toward the bottom of the body 2. An upper opening 11 between the storage canister 1 and the transport cask 10 is sufficiently useful for a plastic working operation for applying the second compressive stress. The transport cask 10 has a thickness d of about 200 mm. As has been discussed, the range from the upper end 2d of the body 2 to the L minimum value is about 300 mm in the typical storage canister 1. In the present embodiment, the upper opening 11 has a radial dimension w of about 125 mm and a depth h (axial dimension) of about 145 mm. The depth h of the upper opening 11 may be almost double the thickness t of the storage canister 1, from a lower end 12 of the welded part of the primary cover member 5 toward the bottom of the primary cover member 5. These dimensions are not limited and can be optionally changed. The formation of the storage canister 1 according to this method cancels all tensile residual stresses while blocking radiation from nuclear fuel, thereby generating a compressive residual stress over the body 2. According to the present embodiment, the first compressive stress is applied beforehand to the range of the body 2 where a tensile residual stress is expected to be generated by welding of the cover 4. This cancels the tensile residual stress generated by welding and reduces a work range of application of the second compressive stress, accordingly. Thus, work can be performed with the small upper opening 11 between the storage canister 1 and the transport cask 10, thereby generating a compressive residual stress over the outer surface of the body 2 while blocking radiation from nuclear fuel. The present embodiment illustrates, but not exclusively, one example of the method to prevent stress corrosion cracking of the storage canister and the storage canister according to the present invention. The method to prevent stress corrosion cracking of the storage canister may include other steps, and the shape and dimensions of the storage canister may be changed. Referring to FIG. 9, for example, the upper opening 11 between the transport cask 10 and the storage canister 12 may be filled with water and then the cover members 5 and 6 may be welded in this state. Specifically, in the method to prevent stress corrosion cracking of the storage canister, the first compressive stress is applied beforehand to the range of the cylindrical body where a tensile residual stress is expected to be generated by welding of the covers, the covers are welded with a compressive residual stress in the range so as to cancel the tensile residual stress, and then the second compressive stress is applied so as to generate a compressive residual stress over the range. The welded part is water-cooled during the welding of the covers, further reducing the range of application of the second compressive stress. FIG. 10 is a graph showing an axial residual stress on the outer surface of the body when the welded part is water-cooled and when the welded part is not water-cooled. FIG. 11 is a graph showing a circumferential residual stress on the outer surface of the body when the welded part is water-cooled and when the welded part is not water-cooled. As shown in FIGS. 10 and 11, a residual axial stress and a residual circumferential stress both reduce the generation region of a tensile stress. Welding during cooling suppresses the expansion of the body, further reducing the axial range where a tensile residual stress is generated after welding. This can achieve a smaller work range for applying the second compressive stress.
	description	The following relates to the nuclear reactor arts, electrical power generation arts, nuclear reactor control arts, nuclear electrical power generation control arts, thermal management arts, and related arts. Nuclear reactors employ a reactor core comprising a mass of fissile material, such as a material containing uranium oxide (UO2) that is enriched in the fissile 235U isotope. A primary coolant, such as light water or heavy water flows through the reactor core to extract heat for use in heating water or another secondary coolant to generate steam, or for some other useful purpose. For electrical power generation, the steam is used to drive a generator turbine. In thermal nuclear reactors, the water also serves as a neutron moderator that thermalizes neutrons, which enhances reactivity of the fissile material. Various reactivity control mechanisms, such as mechanically operated control rods, chemical treatment of the primary coolant with a soluble neutron poison, or so forth are employed to regulate the reactivity and resultant heat generation. In a pressurized water reactor (PWR), the light water (or other primary coolant) is maintained in a subcooled state in a sealed pressure vessel that also contains the reactor core. In the PWR, both pressure and temperature of the primary coolant are controlled. An external pressurizer may be used for pressure control; however, an external pressurizer entails an additional large-diameter pressure vessel penetration to connect the external pressurizer with the pressure vessel. Various internal pressurizer configurations are also known. Disclosed herein are improvements that provide various benefits that will become apparent to the skilled artisan upon reading the following. In one aspect of the disclosure, an apparatus comprises a pressurized water reactor (PWR) including a pressure vessel and a nuclear reactor core disposed in the pressure vessel. A baffle plate is disposed in the pressure vessel and separates the pressure vessel into an internal pressurizer volume disposed above the baffle plate and an operational PWR volume disposed below the baffle plate. The baffle plate includes a transfer passage having a lower end in fluid communication with the operational PWR volume and an upper end in fluid communication with the internal pressurizer volume at a level below an operational pressurizer liquid level range. A vent pipe has a lower end in fluid communication with the operational PWR volume and an upper end in fluid communication with the internal pressurizer volume at a level above the operational pressurizer liquid level range. In some such apparatus, the baffle plate comprises first and second spaced apart plates. In another aspect of the disclosure, an apparatus comprises a pressurized water reactor (PWR) including a pressure vessel configured to contain a nuclear reactor core and a baffle plate disposed in the pressure vessel. The baffle plate separates the pressure vessel into an internal pressurizer volume disposed above the baffle plate and an operational PWR volume disposed below the baffle plate. The baffle plate comprises first and second spaced apart plates. In another aspect of the disclosure, an apparatus comprises a baffle plate configured to be disposed in a pressurized water reactor (PWR) with a first side of the baffle plate facing an internal pressurizer volume and an opposite second side of the baffle plate facing an operational PWR volume. A vent pipe passes through the baffle plate and has first end in fluid communication with the first side of the baffle plate and an opposite second end in fluid communication with the second side of the baffle plate. The first end of the vent pipe is relatively closer to the baffle plate and the second end of the vent pipe is relatively further away from the baffle plate. With reference to FIG. 1, an illustrative nuclear reactor of the pressurized water reactor (PWR) type includes a pressure vessel 10 and a nuclear reactor core 12 disposed in the pressure vessel 10. The reactor core 12 comprises a mass of fissile material, such as a material containing uranium oxide (UO2) that is enriched in the fissile 235U isotope, arranged fuel rod bundles disposed in a fuel basket or other support assembly configured to mount in suitable mounting brackets or retention structures of the pressure vessel 10. The pressure vessel contains a primary coolant up to a level L indicated in FIG. 1. In the PWR configuration, the primary coolant is maintained in a subcooled state in which both pressure and temperature are controlled. In the illustrative PWR of FIG. 1, the pressure is maintained using an internal pressurizer comprising a steam bubble S disposed at the top of the pressure vessel 10. Resistive heaters 14 or another heating device are provided to heat the steam bubble so as to increase the pressure. On the other hand, spray nozzles or spargers 16 are suitably provided to inject cool water or steam into the steam bubble to reduce the pressure. (Note that the control elements 14, 16 are shown diagrammatically). The internal pressurizer is contained within the pressure vessel 10. In the illustrative example, a baffle plate 20 is disposed in the pressure vessel 10. The baffle plate 20 separates the pressure vessel into an internal pressurizer volume 22 disposed above the baffle plate and an operational PWR volume 24 disposed below the baffle plate. The internal pressurizer volume 22 contains a portion of primary coolant extending from the baffle plate 20 up to the level L of the primary coolant in the PWR, and also contains the steam bubble S disposed above the level L. The level L of the primary coolant may vary during normal operation of the PWR within an operational pressurizer liquid level range Lop.range. The operational pressurizer liquid level range Lop.range is to be understood as the allowable range of the level L during any normal mode of PWR operation. A value for the level L that is outside of the operational pressurizer liquid level range Lop.range constitutes abnormal operation requiring intervention of reactor operations personnel. For example, a loss of coolant accident (LOCA) may cause the primary coolant level to decrease below the operational pressurizer liquid level range Lop.range—this is not normal operation, and indeed a LOCA generally results in immediate shutdown of reactor operation. Similarly, some events or conditions may cause the primary coolant level to increase above the operational pressurizer liquid level range Lop.range—again, this is not normal operation. In some cases, deviation of the liquid level range outside of the operational pressurizer liquid level range Lop.range may not call for reactor shutdown, but may instead be remediated control operations that bring reactor operational parameters into normal range, including bringing the level L into the operational pressurizer liquid level range Lop.range. It should also be noted that a particular current operational condition or mode of the PWR (e.g., operation at a particular power output level or a particular primary coolant temperature) may impose a more stringent restriction on the level of primary coolant than Lop.range. As used herein, the operational pressurizer liquid level range Lop.range is to be understood as the allowable range of the level L during any normal mode of PWR operation—a particular normal mode of PWR operation may impose a more stringent restriction of the primary coolant level. By way of illustration, consider levels L1<L2<L3<L4, and two operational modes: a first mode operating at temperature T1 for which the coolant level is restricted to the range [L1, L3] and a second mode operating at a temperature T2>T1 for which the coolant level is restricted to the range [L2, L4]. Assuming for simplicity that these are the only two operational modes for the PWR, the operational pressurizer liquid level range Lop.range is [L1, L4]. With continuing reference to FIG. 1, the illustrative PWR includes a central riser 30 disposed coaxially inside the pressure vessel 10. Primary coolant that is heated by the nuclear reactor core 12 flows upwardly inside the central riser 30 and discharges at a top of the central riser 30 which is proximate to (or in some contemplated embodiments connected with) the baffle plate 20. The discharged primary coolant reverses flow direction and flows downward outside the central riser 30 through an annulus 32 defined by the central riser 30 and the pressure vessel 10. Optionally, the top of the central riser 30 includes a perforated screen 34 to promote flow reversal from the upward direction inside the central riser 30 to the downward direction in the outer annulus 32. Although not illustrated, in some embodiments an integral steam generator is disposed in the annulus 32. In a typical configuration, feedwater (constituting a secondary coolant different from the primary coolant) flows in a generally upward direction either inside or outside one or more steam generator tubes (not shown) disposed inside the annulus 32. The primary coolant flows generally downward through the annulus 32 in the other of the inside or outside of the one or more steam generator tubes. (In other words, the primary coolant may flow generally downward outside the steam generator tube or tubes while the secondary coolant flows generally upward inside the steam generator tube or tubes, or, alternatively, the primary coolant may flow generally downward inside the steam generator tube or tubes while the secondary coolant flows generally upward outside the steam generator tube or tubes). The steam generator tubes may have various geometries, such as vertically straight steam generator tubes, or a helical steam generator tube encircling the central riser 30. A PWR that includes an integral steam generator is sometimes referred to in the art as an integral PWR. Although the integral steam generator is typically located in the annulus 32, it is also contemplated to locate an integral steam generator (or a portion thereof) elsewhere inside the pressure vessel 10, such as inside the central riser 30. In other embodiments, the steam generator is external to the pressure vessel 10, and the primary coolant heated by the reactor core 12 is piped from the pressure vessel 10 to the external steam generator (not shown) via suitable piping. In yet other contemplated embodiments, the PWR is used for a purpose other than generating steam, and there is no steam generator at all. Reactivity control mechanisms are suitably provided to control nuclear reactivity in the reactor core 12. In the illustrative embodiment, a plurality of neutron-absorbing control rods 40 are operated by a control rod drive mechanism (CRDM) or mechanisms 42 to controllably insert or withdraw the control rods 40 into or out of the reactor core 12. Inserting the control rods reduces reactivity, while withdrawing the control rods increases reactivity. The illustrative CRDM 42 is an internal CRDM 42 that is disposed inside the pressure vessel 10; alternatively, the CRDM may be an external CRDM that is disposed outside of and above the pressure vessel 10, with suitable mechanical penetrations to connect with the control rods. Additionally or alternatively, a soluble neutron poison such as boric acid may optionally be added to the primary coolant in controlled amounts to control reactivity. As yet another illustrative example, processes that form voids in the primary coolant can affect reactivity by modifying the moderator action of the primary coolant (these embodiments employ light water, heavy water, or another primary coolant that serves as a neutron moderator), and suitable control of such a process can provide an alternative or additional reactivity control mechanism. The PWR suitably includes other elements that are not illustrated in diagrammatic FIG. 1, such as monitoring sensors, valving and other components for safety systems, an external containment structure, or so forth. Circulation of the primary coolant inside the pressure vessel 10 (e.g., flowing upward through the central riser 30 and downward through the annulus 32 back to the reactor core 12) may be driven by natural convection, or may be actively driven or assisted by primary coolant pumps (not shown). The illustrative PWR pressure vessel 10 is mounted in a generally upright position via a support skirt 44 with a lower portion of the pressure vessel 10 that contains the reactor core 12 disposed underground. (In some contemplated embodiments, the entire pressure vessel 10 may be below ground, with the lower portion of the pressure vessel 10 that contains the reactor core 12 disposed in a deeper recess or pit). While the aforementioned partially or wholly subterranean arrangements are advantageous from a safety standpoint, other arrangements are also contemplated, such as placement of the PWR on a maritime or naval vessel to provide nuclear power for operating the vessel. Moreover, the PWR diagrammatically illustrated in FIG. 1 is an example, and other configurations for the reactor vessel, primary coolant circulation path, and so forth may be employed. In a PWR including an integral pressurizer, such as that shown by way of illustrative example in FIG. 1, the internal pressurizer volume 22 and the operational PWR volume 24 are both contained in the pressure vessel 10, but are separated by the baffle plate 20. There should be sufficient fluid communication across the baffle plate 20 such that pressure changes in the internal pressurizer volume 22 are effective to control the pressure in the operational PWR volume 24. Additionally, the baffle plate 20 contributes to diverting the upwardly flowing primarily coolant discharged from the central riser 30 into the outer annulus 32. It is recognized herein that thermal characteristics of the baffle plate 20 are also advantageously considered. To provide an illustrative example, in one operational mode simulated for a PWR similar to that shown in FIG. 1, the operational PWR volume is designed to operate with primary coolant comprising water in a compressed or subcooled liquid phase. A typical value for the sub-cooled liquid phase is in the range of about 310° C. to about 325° C. To maintain the desired pressure, the internal pressurizer volume 22 is maintained at a higher temperature that preferably corresponds to the saturation temperature of the primary coolant water and is preferably about 5° C. to about 35° C. above that of the subcooled liquid. The water in the pressurizer volume 22 is in the liquid phase below the water level L and in the gaseous phase in the steam bubble S above the water level L. With substantial fluid communication between the two volumes 22, 24, the pressure generated in the higher-temperature pressurizer volume 22 is efficiently transferred to the operational PWR volume 24 to provide pressure control. However, it is recognized herein that the aforementioned substantial fluid communication also implies substantial thermal communication between the two volumes 22, 24. Heat is thus efficiently transferred from the higher temperature pressurizer volume 22 to the lower temperature, and larger, operational PWR volume 24. Consequently, the heaters 14 are operated to maintain the higher temperature of the pressurizer volume so as to maintain the desired pressure. In simulations, about 80 kW of power are input to the heaters 14 to maintain the desired temperature of the pressurizer volume. It is recognized herein that this results in inefficient operation of the PWR, and can have other deleterious effects such as introducing a temperature gradient in the operational PWR volume 24. Accordingly, the disclosed baffle plates are designed to be thermally insulating. Toward this end, the baffle plate 20 is designed to suppress flow of primary coolant between the two volumes 22, 24 during steady state operation. This entails increasing the flow resistance across the baffle plate 20. In the illustrative example, fluid communication across the baffle plate 20 during normal operation is via one or more designated pressure transfer passages 50. Each pressure transfer passage 50 has a lower end in fluid communication with the operational PWR volume 24 and an upper end in fluid communication with the internal pressurizer volume 22 at a level below the operational pressurizer liquid level range Lop.range. This ensures that the upper end of the pressure primary transfer passage 50 remains immersed in liquid prima coolant during any normal operation of the PWR. The relatively higher flow resistance of the baffle plate 20 does reduce transient performance. However, it is recognized herein that a PWR used in power generation or another useful application is typically operated in steady state, with at most small transients being applied, except during startup and shutdown. By suppressing flow of primary coolant between the two volumes 22, 24, convective heat transfer between the two volumes 22, 24 is reduced, which increases the thermal insulation provided by the baffle plate 20. The illustrative baffle plate 20 is also made more thermally insulating by constructing the baffle plate 20 to include a thermally insulating gap. In the embodiment of FIG. 1, the baffle plate 20 comprises first and second spaced apart plates 60, 62 that are separated by a gap 64 that serves as a thermal insulator. Although two spaced apart plates 60, 62 are illustrated, the number of spaced apart plates can be increased to three or more plates to provide further thermally insulating gaps. The plates 60, 62 are suitably metal plates, for example made of steel or another metal comporting with the rigorous environment inside the pressure vessel 10 of the PWR. The relatively high flow resistance provided by the pressure transfer passages 50 advantageously increases the effective thermal insulation provided by the baffle plate 20. However, in some accident scenarios in which pressure builds up inside the pressure vessel 10, this high flow resistance can be problematic. In an accident scenario including pressure elevation, the increasing pressure is conventionally relieved via a suitable relief valve 52, which is suitably operatively connected with the steam bubble S proximate to the top of the pressure vessel 10. In such a situation, the high flow resistance of the baffle plate 20 could result in delayed pressure relief and/or rupture of the baffle plate 20. In the embodiment of FIG. 1, one or more vent pipes 70 are provided to accommodate an accident scenario in which pressure builds up in the pressure vessel 10. The vent pipes 70 provide a larger fluid pathway for relieving pressure. However, it is not desired for the vent pipes 70 to conduct fluid (and hence promote convective heat transfer) during normal operation of the PWR. In the embodiment of FIG. 1, each vent pipe 70 has a lower end in fluid communication with the operational PWR volume 24 and an upper end in fluid communication with the internal pressurizer volume 22, but at a level above the operational pressurizer liquid level range Lop.range. This places the upper end of the vent pipe 70 in the steam bubble S. As a result, primary coolant does not flow through the vent pipe 70 during normal operation of the PWR, and so the vent pipe 70 provides no (or negligible) contribution to heat transfer across the baffle plate 20. On the other hand, in the event of an accident in which pressure inside the pressure vessel 10 rises, the vent pipes 70 are available to conduct fluid (either liquid or gaseous primary coolant) into the internal pressurizer volume 22 so as to be released by the relief valve 52. With reference to FIG. 2, an enlarged view (as compared with the view of FIG. 1) is shown of a variant embodiment that also includes the baffle plate 20 defining the internal pressurizer volume 22 and the operational PWR volume 24, with the steam bubble S located in the pressurizer volume 22. The internal pressurizer of FIG. 2 also includes heaters 14 and the steam vent spray nozzles or spargers 16 for pressure control. The illustrative baffle plate 20 of FIG. 2 also comprises first and second plates 60, 62 spaced apart by the gap 64, and includes pressure transfer passages 50 (only one of which is shown by way of illustrative example in FIG. 2) passing through the baffle plate 20, and further includes vent pipes 70 (again, only one of which is shown by way of illustrative example in FIG. 2). As seen in FIG. 2, a lower end 82 of the vent pipe 70 is in fluid communication with the operational PWR volume 24 and an upper end 84 of the vent pipe 70 extends above the operational pressurizer liquid level range Lop.range, into the steam bubble S. In FIG. 2, a vent pipe support 86 provides support for the upper end 84 of the vent pipe 70 which extends relatively further away from the baffle plate 20 as compared with the lower end of the vent pipe 70. The embodiment of FIG. 2 differs from that of FIG. 1 in the detailed shape of the portion of the pressure vessel 10 defining the internal pressurizer volume 22, and in the use of a different perforated screen 34′ at the upper end of the central riser 30. The illustrative perforated screen 34′ extends from the central riser 30 to the baffle plate 20 such that all upwardly flowing primary coolant discharging at the upper end of the central riser 30 passes through the perforated screen 34′. It should be noted that in some embodiments the perforated screen 34′ is formed integrally with the central riser 30, for example by forming openings (that is, perforations) at the top of the central riser 30 to define the perforated screen 34′. In the embodiments of both FIGS. 1 and 2, the pressure transfer passages 50 are located outside of the perforated screen 34, 34′. At this outer location, the primary coolant flow is transitioning from the upward flow direction to the downward flow direction, and accordingly has a substantial (or, with suitable flow design, entirely) lateral flow component directed parallel with the baffle plate 20. This lateral flow is transverse to the flow direction inside the pressure transfer passages 50, which further reduces flow of primary coolant between the volumes 22, 24. With reference to FIG. 3, the pressure transfer passages 50 are suitably configured to further reduce flow of primary coolant between the volumes 22, 24. In the illustrative pressure transfer passage 50 of FIG. 3, this is accomplished by employing a pressure transfer passage 50 embodied as a surge pipe 90 passing through the baffle plate 20 (that is, in this embodiment, first and second constituent plates 60, 62). The surge pipe 90 has a lower end 92 in fluid communication with the operational PWR volume 24, and an upper end 94 in fluid communication with the internal pressurizer volume 22 at a level below the operational pressurizer liquid level range Lop.range (shown in FIGS. 1 and 2). The lower end 92 of the surge pipe 90 includes a closing plate 100, and fluid communication to the operational PWR volume 24 is via perforations or holes 102 in the sides of the lower end 92. Further reduction in primary coolant flow is provided by an outer coaxial pipe 104. Since primary coolant flow in the operational PWR volume 24 proximate to the lower end 92 is substantially lateral (again, transitioning from the upward flow inside the central riser 30 to downward flow in the outer annulus 32), the outer coaxial pipe 104 promotes formation of a primary coolant stagnation zone at the lower end 92. The illustrative configuration including features 100, 102, 104 is merely an illustrative example of a configuration of the pressure transfer passage 50 to reduce flow of primary coolant between the volumes 22, 24. Various other arrangements of baffles, constrictions, or flow barriers are also contemplated to provide reduced flow of primary coolant between the volumes 22, 24. Any such arrangements or configurations should provide sufficient fluid communication to enable the pressure transfer passage to perform its primary function of enabling control of pressure in the operational PWR volume 24 by adjustment of pressure in the internal pressurizer volume 22. The extent of fluid communication sufficient for this purpose depends upon the expected normal operating pressure, the acceptable (that is, designed) transient intervals, the type of primary coolant, and so forth. With reference to FIGS. 4 and 5, various approaches can be used to provide thermal insulation by construction of the baffle plate 20 comprising first and second plates 60, 62 spaced apart by the gap 64. In FIG. 4, the two plates 60, 62 are spaced apart by the gap 64, but are not sealed at their periphery. Suitable standoffs 110 secure the plates 60, 62 together and define the gap 64. In the embodiment of FIG. 4, the gap 64 is not a sealed volume. Rather, the first and second spaced apart plates 60, 62 define an unsealed volume 64 that fills with water when the baffle plate 20 is immersed in water. Thermal insulation is provided because water (or other primary coolant) in the unsealed volume 64 is stagnant and not flowing (or at least not rapidly flowing). Thus, the primary coolant in the unsealed volume 64 conveys heat primarily by thermal conduction, but not by thermal convection. If further insulation is desired, an embodiment such as that of FIG. 5 can be employed. In this alternative embodiment, a baffle plate 20′ comprises two plates 60, 62 that are spaced apart by the gap 64 in which the plates 60, 62 are sealed at their periphery by an annular seal 112 of metal or another material that is robust against the environment of the PWR. As a result, the gap 64 is a sealed volume in the embodiment of FIG. 5. The sealed volume can be filled with a gas 114, such as air, nitrogen, or so forth. This approach ensures that heat is conveyed across the gap 64 only by thermal conduction. In a further variation, it is contemplated for the sealed volume to be an evacuated volume (that is, “containing” a vacuum). The illustrative baffle plates 20, 20′ provide substantial thermal insulation. However, other thermally insulating baffle plates are also contemplated. For example, another contemplated baffle plate comprises a single plate (and hence no gap), with the single plate comprising a thermally insulating material that is robust in the environment inside the pressure vessel 10 of the PWR. Steady state simulations have been performed for the baffle plate 20 of FIG. 4 in the pressurizer configuration of FIG. 2 with pressure transfer passages embodied as shown in FIG. 3 and further including the vent pipes 70. These simulations used the operating conditions of subcooled primary coolant in the operational PWR volume 24, and the internal pressurizer volume 22 containing primary coolant water at a higher temperature approximately 11° C. higher than the sub-cooled temperature corresponding to the saturation temperature of the primary coolant water. Using a single steel plate with high flow conductance to separate the two volumes 22, 24, the simulations indicated about 80 kW of power to the heaters 14 was sufficient to maintain the pressurizer at the saturation temperature. In contrast, when using the disclosed baffle plate 20 this heating was reduced to a few kW. The steady state simulations indicated that most of the improved performance was due to limiting flow of coolant across the baffle plate 20 in the steady state, with the use of the spaced apart plates 60, 62 providing secondary thermal improvement. The vent pipes 70 are operative in certain accident scenarios. For example, in a loss of coolant accident (LOCA) scenario in which there is a full guillotine break a pressure relief valve nozzle 52, the vent pipes 70 minimize the pressure acting on the baffle plate 20. The vent pipes 70 allow the pressurized water (or other pressurized primary coolant) in the operational PWR volume 24 to bypass the pressure transfer passages 50 thus minimizing the pressure differential across the baffle plate 20. The vent pipe supports 86 allow for differential expansion between the vent pipes 70 and the shell of the pressure vessel 10. With reference to FIGS. 6-8, the mounting of the baffle plate 20 in the pressure vessel 10 can employ various connection configurations. Referring to FIG. 6, one embodiment for supporting the baffle plate 20 employs a lower support ring 120 that is welded to the shell 122 of the pressure vessel 10 with an upper support ring 124 that is also welded to the shell 122, that restrains the baffle plate 20 against any differential pressure across the baffle plate 20 as would be the case during a LOCA accident in which there is a full guillotine break at the pressure relief valve nozzle 52. In connection configuration of FIG. 6, flow across the baffle plate 20 via the periphery connection with the shell 122 can be suppressed or blocked entirely by including wedges 126 disposed between the upper metal plate 60 of the baffle plate 20 and the shell 122 or the upper support ring 124. The wedges 126 allow differential expansion between the baffle plate 20 and the shell 122 while maintaining a fluid seal. With reference to FIGS. 7 and 8, another connection embodiment comprises attaching the lower plate 62 of the baffle plate 20 to the shell 122 of the pressure vessel 10 by welding. The upper plate 60 is supported on the lower plate 62 in this configuration by the standoffs 110. Any potential displacement of the shell 122 due to pressure dilation and temperature expansion is suitably accommodated by an intervening component disposed between the shell 122 and the lower plate 62 to absorb the differential expansion. In the embodiment of FIG. 7, this intervening component comprises a tongue 130 formed by removing a portion of the shell 122 by etching or a mechanical grinding process or so forth. In the embodiment of FIG. 8, this intervening component comprises an intervening bracket 132 welded onto the shell 122. The connection configurations described with reference to FIGS. 6-8 are illustrative examples, and other connection configurations that accommodate differential thermal expansion and shell displacement while maintaining a suitable fluid seal are also contemplated. The preferred embodiments have been illustrated and described. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
	description	The present application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Ser. No. 63/033,915 filed on Jun. 3, 2020, the disclosure of which is incorporated herein by reference in its entirety. The present patent application is a continuation-in-part (CIP) of U.S. non-provisional patent application Ser. No. 16/285,199 filed on Feb. 26, 2019, and claims priority to said U.S. non-provisional patent application under 35 U.S.C. § 120. This U.S. non-provisional identified patent application is incorporated herein by reference in its entirety as if fully set forth below. The present invention relates in general to deeply located human-made caverns and more specifically to construction, implementation, and usage of the deeply located human-made caverns for disposal/storage of hazardous waste materials, wherein deeply located may be within a subterranean geological formation at a predetermined depth below the Earth's surface. A portion of the disclosure of this patent application may contain material that is subject to copyright protection. The owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyrights whatsoever. Certain marks referenced herein may be common law or registered trademarks of third parties affiliated or unaffiliated with the applicant or the assignee. Use of these marks is by way of example and should not be construed as descriptive or to limit the scope of this invention to material associated only with such marks. Implementation of relatively large diameter (e.g., six feet or more) deep human-made caverns in underground formations (e.g., 2,000 feet or so and deeper) has been a goal of several and very different industries. These industries vary from the nuclear warfare groups that desire such deeply located human-made caverns for underground atomic weapons testing to other the industries that desire to store large volumes of fluids and/or gases of various kinds. In the past, it has been challenging, dangerous, and expensive to try to store radioactive and/or nuclear materials (such as waste materials) in underground caverns except for those cases where solid quantities of material are stored in barrels, individual capsular containers, slurry material, open pits and also within shallow mines which are very close to a terrestrial surface (of the Earth). That is, in the past, deeply located human-made caverns have not been so utilized. Also, in industrial settings, the storage of large quantities of material has always been in near-surface caves built out of native rock or in somewhat deep natural salt deposits in which the caverns have been leached out by circulating water action. Both methods (i.e., near-surface caves built out of native rock or in somewhat deep natural salt deposits) have significant costs and time constraints. A better method is needed to facilitate the development and/or construction of deep human-made caverns which have significant capacity to store, dispose, and/or contain various types of materials, waste or otherwise. The inventions herein provide at least some teachings, systems, methods, and/or mechanisms utilizing available engineering and wellbore systems are used in the construction of deeply located human-made caverns. Underground human-made caverns have been used to store natural gas, hydrocarbon liquids, waste-water, petroleum products, and other commercial products for many decades. These caverns have generally been drilled into and/or leached from subsurface salt domes or salt formations which have been formed over geologic time by salt intrusions or depositions from regional seas or other long-gone aqueous environments. Human-made caverns within salt deposits are typically created by injecting fresh water into subterranean salt formations and withdrawing the resulting brine. This process is referred to as solution mining. Over time, numerous human-made caverns in salt deposits have been solution mined by the petroleum industry for use in storing hydrocarbons like the Strategic Petroleum Reserves which holds hundreds of millions of barrels of crude oil; and for disposing of nonhazardous oilfield wastes (NOW). However, to date (circa 2020), human-made caverns in salt deposits have not been routinely implemented to store large quantities of dangerous waste material. Atomic testing agencies have provided prior art related to implementation of large diameter underground caverns. About $57,000,000 (1967 USD) was spent over two years on a drilling effort in Alaska. The Parker Drilling company of Tulsa, Okla., in 1968 contracted with and drilled two secret wellbores in Alaska for the NRC (Nuclear Regulatory Commission). The first wellbore was a 90-inch diameter to a depth of 6,120 feet and the second was a 120-inch diameter wellbore to a depth of 4,427 feet. The operation costs were prohibitive. The drill rig was specialized and was later relegated to a museum in western Oklahoma. These two prior art wellbores were “special-built and dedicated” requests by the NRC. These wellbore types would not be able to be modified for general utilization in the nuclear waste disposal process because of the special requirements stipulated by the NRC regarding physical dimensions, capacity, and wellbore safety were geared for nuclear weapons testing. A very different technology from nuclear waste disposal. Today (2020), several operating well service companies like Halliburton, Schlumberger, and others have developed unique drilling and reaming systems that allow an existing wellbore to be “reamed” out to a larger diameter to provide more flexibility in drilling or well servicing operations. This type of reaming operation is significantly quicker and less expensive than drilling the final sized enlarged wellbore directly from the surface. These additional reaming operations typically are only able to enlarge the original wellbore by at most 75% of its original size. For example, a 12-inch initial wellbore may be enlarged to about 20 inches; and/or a 20-inch diameter initial wellbore may be enlarged to about 35 inches. These enlarged diameters of 20 to 35 inches are not sufficient to provide the large volumes needed to store or dispose of the millions of gallons/tons of material that is customarily available for disposal/storage. A means is needed to enlarge initial wellbore up to and including 120 inches diameter depending on depth, to provide the significant storage volumes in some rock formations. These prior art approaches to making large diameter wellbore suitable for deep disposal or storage are limited (e.g., they do not provide a sufficiently enlarged diameter). Better systems are needed. The better systems combine various aspects of available rotary drilling and jet drilling technologies to provide a system that can economically and in a reasonably short time provide a large diameter human-made cavern of sufficient size/depth to make disposal/storage therein an economic reality. This invention expands on the boundaries of the prior art, and broadens the scope of the existing prior art technologies, with the embodiments illustrated herein, able to combine jet drilling processes with the rotary drilling systems to formulate system and methods for building/constructing large diameter human-made caverns (e.g., of 120 inches in diameter or so) in a rapid manner and in an economical fashion for waste disposal and/or storage. The jet drilling processes may be modified oilwell drilling operations, in which coiled tubing or high-pressure jointed pipe conveys high-pressure fluid to a downhole jet drill tool assembly to typically penetrate or carve out a given rock formation. The downhole jet drill assembly may turn in a short radius of about three (3) inches. The operating jet drill pressures can range up to 20,000 psi (pounds per square inch) or more and flow rates are generally less than 10 gallons per minute. Jet drilling processes may carve out a section of essentially void space from a formation occur in a matter of minutes. The jet drill assembly itself may be manipulated by a series of programmed indexing or translational control measures. The operational jet drilling system can be deployed in either of two methods from the surface. The high-pressure jointed pipe allows the drilling operator to complete the entire jet drilling process utilizing a workover rig. In contrast, coiled tubing method allows for a shorter trip time for deeper disposal operations. These deep zones would be formations from 5,000 feet to 10,000 feet or more deep. Jet drilling technology has been developed over the last four decades. Some aspects may even be routine in some oilfield operations. The required equipment such as, high pressure pump, control systems, high pressure tubes, and nozzle configurations are well known and may be modified as required to operate under different downhole conditions as required in this invention. Operationally, the high pressure jet nozzle accelerates the fluid, with abrasive particles therein, to speeds close to 1,000 feet/second producing four main rock (formation) penetration mechanisms. These mechanisms are: 1) surface erosion; 2) hydraulic fracturing; 3) poro-elastic tensile failure; and 4) cavitation. Jet drill functionality and configuration of the jet nozzles may allow the jet nozzle to move away from the wellbore a predetermined distance into the formation thus enlarging the jetted (excavated) zone or cavity. In some embodiments of this invention, jet movement into the formation may be a minimal distance. Rock penetration rates between 0.5 foot/minute to 10 feet/minute have been achieved in the field. In the formations contemplated in this invention operating penetration rates between 0.5 foot/minute to 2 feet/minute may be expected. In some extreme published cases, some 10,000 psi fluid pressure jet drilling tools have pushed (moved) their nozzles into the formation forming a lateral (radially extending) wellbore up to 700 feet long and with diameters up to 4 inches in some cases. The sequential use of high-pressure jet drill processing with large diameter rotating reamer systems may together be used to implement a waste disposal system shown in the embodiments herein, which can meet the disposal and/or storage needs of many diverse industries. There are long felt, but unmet, needs for devices, apparatus, tools, machines, means, systems, mechanisms, and/or methods that would allow the development of large diameter human-made caverns for storage and/or disposal of waste; and wherein such large diameter human-made caverns may be located deeply and far below the Earth's surface; and wherein the waste may be high-level nuclear waste which may exist in a variety of difficult to manage physical forms (such as, but limited to, liquids, sludges, powders, solids, etc.). A need, therefore, exists for new systems and/or methods, that are also economic and implementable in relatively short time periods, for safely disposing of waste, such as, but not limited to radioactive waste, in a controlled manner along with depositing such waste in a system that is designed to meet the requirements of public acceptance along with regulatory guidelines/requirements. It is to these ends that the present invention has been developed. To minimize the limitations in the prior art, and to minimize other limitations that will be apparent upon reading and understanding the present specification, the present invention may describe systems and/or methods of waste disposal that use human-made caverns that are constructed within deep geological formations. Some embodiments of the present invention may describe means, systems, mechanisms, and/or methods for implementing large diameter human-made caverns configured for (capable of) the storage and/or disposal of radioactive materials within the human-made subterranean cavities within deep geological formations. In some embodiments, such stored and/or disposed of radioactive materials may be retrieved for auditing, inspection, technical, and/or operational reasons. For example, and without limiting the scope of the present invention, a given human-made cavern may be constructed by first drilling out a (substantially) vertical wellbore to or into a deep geological formation; then a bottom portion of that vertical wellbore may jet drilled, using an abrasive jetting fluid and at least one jetting tool, to form a launch chamber of void volume, that is sized to fit a reaming tool in its deployed open configuration; the jet drilling equipment may then be removed; the reaming tool, in a closed configuration, may then be inserted into the vertical wellbore for landing in the launch chamber; the reaming tool is then deployed into its open configuration while in the launch chamber; reaming operations, using the deployed and open reaming tool, then occur from the launch chamber directed downwards within the deep geological formation, forming a given human-made cavern. The newly formed human-made cavern may then be conditioned and/or configured for receiving amounts of the waste for long-term disposal and/or storage. Quantities of the waste may then be loaded into that human-made cavern. The human-made cavern, with its waste, may then be closed and/or sealed off. It may be an object of some embodiments to provide methods of the types described herein wherein a given human-made cavern of substantial volumetric capacity may be formed in a deep geologic formation being several thousand feet below the Earth's surface and wherein the human-made cavern may be several thousand feet in vertical extent with a reasonably large diameter of several feet (e.g., three (3) to ten (10) feet). A human-made cavern of this size can provide close to 1,000,000 gallons of liquid waste storage. By enlarging a pilot wellbore, once a sufficient depth may be reached, to a significant diameter and continuing to vertically drill-out the given human cavern for up to several thousand feet, may produce such a permanent human-made phenomenon for waste storage and/or for disposal. Briefly, the human-made cavern building systems and methods in accordance with some embodiments of this invention may achieve the intended objectives by including the steps of: drilling a pilot well (that may be substantially vertical) which intersects a deep geologic formation; and creation of a small “launch chamber” by jet drilling out a circular/cylindrical chamber of limited size and extent below the pilot wellbore (at a bottom of the pilot wellbore); removing the jet drilling equipment used for jet drill out the launch chamber; inserting an expandable downhole reamer tool in a “closed mode” (closed configuration) which is capable of being expanded to its fullest extent, the “open mode” (open configuration) in the launch chamber, and finally drilling the disposal or storage human-made cavern with the expanded reamer (in the open configuration) to a predetermined/designed depth. The reamer tool is then closed and in the “closed” mode is returned to the surface through the initial pilot wellbore. Recently (2018), an oil well service company has published that it successfully drilled a 54-inch wellbore during an offshore well drilling from a drilling platform. Modifying such oilfield drilling technology and combining diverse drilling technologies allows the implementation of embodiments of the present invention. The ability to economically provide a human-made cavern of sufficient size and volume, for safe disposal of substantial quantities of waste is completely feasible today with the systems and/or methods described herein. What is required is more than just the ability to store some small amount of waste in a single “narrow” vertical wellbore, however, there are needs for storage of massive quantities of waste and the storage in limited vertical wells may not be economically practical. Currently the United States Department of Energy has made attempts to store (dispose) of quantities of HLW in the lowermost sections of a single vertical wellbore. This prior art approach has at least two significant drawbacks: (a) the volumes stored in a small diameter, e.g., less than a nine (9) inch wellbore, is miniscule compared to the current disposal volumes on the Earth's surface waiting and needing to be disposed of properly in a safe long-term solution; and/or (b) vertically stacking capsules of waste material whose density may be as high as 19 gm/cc (grams per cubic centimeter) creates excessive compressive forces acting on the walls of the wellbore casing potentially leading to burst/rupture/failure conditions. Some of the technical drivers that have allowed the embodiments of present invention herein to be implemented may be as follows: jet drilling improvements, drilling rig improvements, and/or some specific technological improvements. The jet drilling systems may be controllable and with abrasive fluids have achieved significant progress in drilling “drainholes” at great depths in many consolidated and unconsolidated and metamorphic rocks for oil and gas production. Drilling rig features have improved including, but not limited to: increased hydraulic pressure availability at the drill bit; available drilling rig horsepower up to as much as 4,000 hydraulic horsepower; available pump horsepower; available rig capacity up to 2,000,000 pounds of dead weight lift is available and rigs with high levels of “push down” capacity for drilling; high downhole drilling fluid pressures can be maintained; drilling rig ability to pump slurries of high density, pounds per gallon (ppg) have increased considerably; and remote and automatic control software for rig operations. Specific technological improvements that pertain to the under-reaming operations and under-reaming equipment have allowed successful under-reaming needed to make and manage large diameter human-made caverns. Some of these improvements may include: hydraulically actuated reamer elements expandable and retractable with pump pressure and downhole RFID (radio frequency ID) triggering with injected RFID tags; cutter arms move upward and out simultaneously from the reaming tool body; fail-safe cutter arm retraction; reverse actuating mechanism maintains that the reaming tool is open, while drill string weight prohibits tool closure; unrestricted fluid flow through internal diameters of the wellbore tubular goods; roller cone cutters are specifically designed for the under-reamers and are consistent with downhole diameters; reamer bodies machined from heat-treated steel bar, giving it exceptional strength; jet nozzles near the cutters allow for cutter washing and cooling; and a variety of cutting structures is available to facilitate the reaming process. It is an objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the human-made caverns have relatively large diameters (e.g., from three (3) feet to ten (10) feet). It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the human-made caverns have relatively long (substantially) vertical lengths (e.g., from 1,000 feet to 10,000 feet). It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the human-made caverns are configured for and capable of long-term storage/disposal of radioactive materials. It is another objective of the present invention to provide systems and/or methods for sequestering high-level nuclear waste (HLW) (and/or the like) in large enough volumes and at a considerable enough distance below the surface of the Earth to maintain the highest level of safety as possible. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the human-made caverns are configured for and capable of long-term storage/disposal of waste materials. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein construction of the human-made caverns is facilitated by down-hole reaming tool(s). It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein use of down-hole reaming tool(s) is facilitated by constructing a launch chamber with a volume of sufficient size to permit expansion of the reaming tool(s) into an open configuration. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein when the reaming tool(s) are not being operated for reaming operations, lowering and raising of the reaming tool(s) through wellbores (of relatively smaller diameter(s)) is done while the reaming tool(s) are in a substantially closed configuration. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein construction of launch chambers is facilitated by use of jet drilling equipment. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, use of jet drilling equipment is done by horizontal/rotational indexing and vertical indexing. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the jet drilling is done at high-pressures and/or with abrasive additives added to (included in) the jetting fluid. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein a given human-made cavern is connected to and located below a given launch chamber. It is another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the deep geological formations have predetermined properties for making the systems and/or methods safer, more efficient, and/or cost effective than prior art/conventional disposal systems/methods. It is yet another objective of the present invention to provide systems and/or methods for constructing human-made caverns in deep geological formations, wherein the human-made caverns are configured for and capable of long-term storage/disposal of radioactive materials, wherein the systems and/or the methods are safer, more efficient, and/or cost effective than prior art/conventional disposal systems/methods. Recapping at least some of the above-noted objectives, some embodiments may provide means, systems, mechanisms, and methods for the implementation of human-made caverns using a sequential combination of drilling technologies (e.g., mechanical/rotatory drilling, jetting drilling, and/or reaming). These and other advantages and features of the present invention are described herein with specificity so as to make the present invention understandable to one of ordinary skill in the art, both with respect to how to practice the present invention and how to make the present invention. The preceding and other steps, objects, and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred method as illustrated in the accompanying drawings. 1 drilling rig 1 2 surface facilities 2 2a jet fluid supply (reservoir) 2a 2b pump means 2b 3 terrestrial ground-level 3 4 near surface formations 4 5 vertical pilot wellbore 5 6a high-pressure conduit 6a 6b drill pipe apparatus 6b 6c jet drill conduit centralizer 6c 7 launch chamber 7 8 volume inside launch chamber 8 9 jet drill fluid pipe 9 10 jetting tool 10 10a jetting tool device in upper position 10a 10b jetting tool device in lower position 10b 11 abrasive jet flow 11 11a channel jetted (carved) in formation rock 11a 12 reaming tool 12 12a large diameter moveable cutting arm 12a 12b small diameter moveable cutting arm 12b 12c drill string 12c 13 expandable and retractable cutting arm 13 14 human-made cavern 14 15 disposal formation rock 15 16 direction of motion of moveable reamer arm 16 17 waste material 17 18 horizontal and rotational indexing direction of jet drilling 18 19 vertical indexing direction of jet drilling 19 20 strata demarcation 20 600 method of forming the initial vertical wellbore 600 601 step of locating wellsite and setting up rig 601 603 step of preparing surface facilities 603 605 step of drilling vertical wellbore 605 607 step of removing rotary equipment and deploying jet drill system 607 609 step of landing the jet drill device in vertical wellbore 609 700 method of jet drilling the launch chamber below the vertical wellbore 700 701 step of deploying the jet drill system at bottom of vertical wellbore 701 703 step of initiating jet drill system 703 705 step of positioning jet drill device 705 707 step to control channel size in host rock 707 709 step of horizontally indexing jet drill 709 711 step of completing horizontal rotational jet drilling 711 713 step of vertically indexing jet drill 713 715 step of jet drilling at higher level 715 717 step of checking launch chamber dimensions 717 719 completing launch cavity 719 721 step of retrieving jet drill equipment 721 800 method of forming the man-made cavern with expanded reamer 800 801 step of deploying reamer tool in closed mode 801 803 step of expanding the reamer tool arms 803 805 step of using surface drill rig system to operate the reamer tool 805 807 step of collapsing and retrieving reamer tool 807 809 step of preparing disposal cavity 809 811 step of introducing waste into cavern 811 813 step of stopping operations 813 As noted above, embodiments of the present invention may describe means, systems, mechanisms, and/or methods for the implementation and construction of large diameter human-made subterranean caverns within deep geological formations, wherein such human-made caverns are configured for long-term storage and/or disposal of predetermined materials. The predetermined materials may or may not be waste. In this patent application, the terms “radioactive material,” “radioactive waste,” “nuclear material,” “nuclear waste,” and/or “high-level nuclear waste” (HLW) may be used interchangeably herein. In this patent application, the terms “cavern,” “cavity,” and/or “chamber,” may be used interchangeably with the same meaning. Further, “cavern,” “cavity,” and/or “chamber,” may mean an at least substantially hollow void space that may be human-made. However, “launch chamber” and “human-made cavern” may refer to different types of human-made structures that may be constructed in different ways. In this patent application, “disposal formation rock,” “matrix rock,” “host rock,” and/or “deep geologic formation” may be used interchangeably; and may refer to a rock structure within a deep geological formation that may be hosting (housing) one or more human-made caverns. In this patent application, the terms “well” and “wellbore” may be used interchangeably and may refer to (substantially) cylindrical drilled out elements implemented in design and/or installation processes of some embodiments of the present invention. In this patent application, the terms “single well” or “common well” may refer to a wellbore that may be shared. In this patent application, the term “pilot” may refer to a first or initial wellbore that may be drilled out from a given site on a terrestrial surface of the Earth, using a given drilling rig. Often such a pilot wellbore may be substantially vertical. In some embodiments, a pilot wellbore may be a single wellbore, a common wellbore, and/or a shared wellbore. In this patent application, the term “ream” and “under-ream” may be used interchangeably to mean the enlarging of a wellbore, hole, and/or void space in a rock medium, such as a portion of a given deep geological formation. In this patent application, “vertical” and “horizontal” may be with respect to Earth's terrestrial surface at a given drill site. That is, “horizontal” may be substantially parallel with respect to Earth's terrestrial surface at the given drill site; and “vertical” may be substantially orthogonal/perpendicular with respect to Earth's terrestrial surface at the given drill site. Or in the alternative, “vertical” and “horizontal” may be with respect to Earth's local gravitational field vector at a given drill site. That is, “vertical” may be substantially parallel with respect to Earth's local gravitational field vector at the given drill site; and “horizontal” may be substantially orthogonal/perpendicular with respect to Earth's local gravitational field vector at the given drill site. In this patent application, “vertical wellbores” need not be geometrically perfectly vertical; but rather may be substantially vertical (e.g., more vertical than horizontal). In this patent application, “lateral wellbore” and “horizontal wellbore” may be used interchangeably. Further, “lateral wellbores” or “horizontal wellbores need not be geometrically perfectly horizontal; but rather may be substantially horizontal (e.g., more horizontal than vertical). Note, unless an explicit reference of “vertical wellbore” or “lateral wellbore” (i.e., “horizontal wellbore”) accompanies “wellbore,” use of “wellbore” herein without such explicit reference may refer to vertical wellbores or lateral wellbores, or both vertical and lateral wellbores. In this patent application, the term “launch chamber” and “launch system” may be used to describe a (human-made) chamber which is developed below the initial pilot wellbore (or at the bottom of the initial pilot wellbore) by jet drilling equipment and actions. This “launch chamber” may be a location into which a closed reamer tool may be inserted from the Earth's terrestrial surface and then opened/expanded completely for subsequent reaming operations used for construct a given human-made cavern. The launch chamber is constructed using jet drilling using fluid mechanics; whereas, the given human-made cavern is constructed from reaming operations using a reaming tool of mechanical/rotary mechanics. In this patent application, the term “indexing” may be used to describe a mechanical process in which a device such as a jet drill (or the like) may be moved incrementally a (small) angular distance (rotation) and/or a (small) linear distance in a given plane to a new position to continue jet drilling operations at the new position. Indexing can be in any of three different axes and/or directions. In some embodiments, of the present invention such indexing of a given jet drill (or the like) may done horizontally, rotationally, and/or vertically. In this patent application, the term “jet drill” may be used to describe a mechanical device in which a highly pressurized abrasive fluid is hydraulically discharged/ejected through a nozzle, orifice, and/or a jet, with sufficient force/pressure and/or with fluid properties (e.g., abrasive properties) to cut through solid material, including portions of a given deep geological formation. These “jet drills” may have one or multiple nozzles strategically placed in a radial system or linear system to accelerate the cutting forces/pressures of the abrasive fluid jets. The terms “jet drilling,” “jetting,” and/or “hydraulic jetting” may be used interchangeably to describe the mechanical process of cutting reservoir rock by hydraulically pressured abrasive filled liquids. The novel features which are considered characteristic for various embodiments of the invention are set forth in the appended claims. Embodiments of the invention itself, however, both as to its construction and its methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of the specific embodiments when read and understood in connection with the accompanying drawings. Attention is called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described within the scope of the appended claims. These and other advantages and features of the present invention are described herein with specificity so as to make the present invention understandable to one of ordinary skill in the art, both with respect to how to practice the present invention and how to make the present invention. In the following discussion that addresses a number of embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part thereof, where depictions are made, by way of illustration, of specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the invention. Note, FIG. 1A through FIG. 1H may be directed to various aspects of launch chambers 7. In some embodiments, a given launch chamber 7 may be formed at a distal/terminal portion of a given substantially vertical wellbore 5. In some embodiments, a purpose of a given launch chamber 7 may be to provide sufficient space, area, room, and/or volume (see e.g., volume 8) for deployment, expansion, extension, retraction, and/or operation of a given reaming tool 12, wherein the given reaming tool 12 may then be used for forming at least one human-made cavern 14 from the given launch chamber 7. That is, in some embodiments, a given launch chamber 7 may be used to facilitate forming a given human-made cavern 14 by permitting use of a given reaming tool 12. In some embodiments, jet drilling may be used to form a given launch chamber 7; whereas, reaming via reaming tool 12 may be used to form a given human-made cavern 14. In some embodiments, reamer tool 12 may be opened and/or closed from inside a given launch chamber 7, from which reamer tool 12 may be retrieved to terrestrial ground-level 3 via the smaller diameter vertical wellbore 5. In some embodiments, a given human-made cavern 14 may be used to receive waste material(s) 17 therein for disposal and/or storage purposes. Note, reaming tool 12, human-made cavern 14, and waste material(s) 17 are not shown in FIG. 1A through FIG. 1H. In some embodiments, waste material(s) 17 may be hazardous, dangerous, radioactive, portions thereof, combinations thereof, and/or the like material(s). In some embodiments, waste material(s) 17 may be one or more of: nuclear waste, radioactive waste, high-level nuclear waste (HLW), spent nuclear fuel (SNF), weapons grade plutonium (WGP), uranium-based waste products, depleted uranium products, depleted uranium penetrators (DUP), uranium hexafluoride (UF6), portions thereof, combinations thereof, and/or the like. In some embodiments, waste material(s) 17 may be in a predetermined form/format. In some embodiments, waste material(s) 17 may be in one or more forms/formats of: solid, liquid, liquefied, slurry, pellet, powder, brick, spherical, ball, gel, rod, cylindrical, briquette, foam, portions thereof, combinations thereof, and/or the like. In some embodiments, waste material(s) 17 may be received into a given human-made cavern 14 for disposal and/or long-term storage. In some embodiments, a given human-made cavern 14 may be located entirely within a given disposal formation rock 15. See e.g., FIG. 3 for waste material(s) 17. FIG. 1A may show a schematic side view of various components that may be used in some embodiments of the invention with respect to forming a given launch chamber 7. In some embodiments, a given launch chamber 7 may be formed in disposal formation rock 15. In some embodiments, disposal formation rock 15 may be located at least some predetermined distance (depth) from a terrestrial ground-level (surface) 3. In some embodiments, “Earth's surface” and “terrestrial ground-level” may be used interchangeably herein and associated with reference numeral 3 in the relevant figures. In some embodiments, disposal formation rock 15 may also be referred to as “deep geologic formation” or as “host rock” or as “matrix rock.” In some embodiments, disposal formation rock 15 may be located substantially from about 2,000 feet to about 30,000 feet below terrestrial ground-level 3, plus or minus 1,000 feet. In some embodiments, disposal formation rock 15 (i.e., the deep geological formation) may be located substantially from 2,000 feet to 30,000 feet, plus or minus 1,000 feet, substantially vertically below the drill site. In some embodiments, disposal formation rock 15 may be one or more of: an igneous rock formation, a metamorphic rock formation, a sedimentary type rock formation, portions thereof, combinations thereof, and/or the like. In some embodiments, disposal formation rock 15 may have desirable and/or required properties to contain the waste material(s) 17 over long time intervals (e.g., of at least one thousand years) and may be able to minimize migration of waste material(s) 17 and/or its radionuclides away from the human-made caverns 14 that are housing the waste material(s) 17. In some embodiments, at least some of desired and/or required properties of disposal formation rock 15 may be demonstrated by petrophysical analysis prior to instituting a given human-made cavern 14 therein. In some embodiments, disposal formation rock 15 may have geologic properties that make the storing/disposal of waste material(s) 17 within disposal formation rock 15 relatively safe. For example, and without limiting the scope of the present invention, in some embodiments, disposal formation rock 15 may have one or more of the following geologic properties: structural closure, stratigraphically varied, low porosity, low permeability, low water saturation, and reasonable clay content. In some embodiments, it may be desirable to locate, create, form, and/or build one or more human-made cavern(s) 14 within disposal formation rock 15. Continuing discussing FIG. 1A, in some embodiments, disposal formation rock 15 may be reach by drilling at least one substantially vertical (pilot) wellbore 5 from terrestrial ground-level 3 to disposal formation rock 15, using at least one drilling rig 1. In some embodiments, surface drilling rig 1 may be an apparatus that drills the vertical pilot wellbore 5. In some embodiments, drilling rig 1 may be located on terrestrial ground-level 3. In some embodiments, drilling rig 1 may be used for one or more of: drilling substantially vertical (pilot) wellbore 5, for landing and/or operating jet drilling equipment; for landing and/or operating reamer tool 12; for forming a human-made cavern 14 using reamer tool 12; for inserting waste material(s) 17 into a given human-made cavern 14; portions thereof; combinations thereof; and/or the like. In some embodiments, drilling rig 1 may have supplementary features to allow safe handling of the waste material 17, such as, but not limited to, radiation shielding. In some embodiments, drilling rig 1 may be substantially as a drilling rig used in oil-field drilling, pumping, and/or maintenance operations. Continuing discussing FIG. 1A, in some embodiments, a given vertical wellbore 5 may be at least substantially vertical. In some embodiments, vertical wellbore 5 may be perfectly vertical to mostly vertical. In this context vertical may be substantially orthogonal with respect to terrestrial ground-level 3; and/or vertical may be substantially parallel with a vector of Earth's gravitational field at a given drill site on terrestrial ground-level 3. In some embodiments, vertical wellbore 5 may be a pilot wellbore in the sense that vertical wellbore 5 may be a first/initial wellbore drilled at a given drill site on terrestrial ground-level 3. In some embodiments, subsequent drilling operations may widen a diameter of at least a portion of vertical wellbore 5 and/or may lengthen a depth/distance of vertical wellbore 5. In some embodiments, vertical wellbore 5 may run from terrestrial ground-level 3 to disposal formation rock 15. In some embodiments, vertical wellbore 5 may run into at least a portion of disposal formation rock 15. In some embodiments, once vertical wellbore 5 may be formed, at least some interior surfaces of vertical wellbore 5 may be lined with casing/piping, with cement, portions thereof, combinations thereof, and/or the like. In some embodiments, a given section of vertical wellbore 5 may have a predetermined length. In some embodiments, a given section of vertical wellbore 5 may have a minimum predetermined length (e.g., to run from terrestrial surface 3 to disposal formation rock 15). In some embodiments, a given section of vertical wellbore 5 may have a length selected from a range of 2,000 feet to 25,000 feet, plus or minus 1000 feet. In some embodiments, a given section of vertical wellbore 5 may have a length selected from a range of 2,000 feet to 25,000 feet, plus or minus 100 feet. In some embodiments, a given section of vertical wellbore 5 may have a predetermined diameter. In some embodiments, a given section of vertical wellbore 5 may have a minimum predetermined diameter (e.g., to accommodate a given reaming tool 12 in its substantially collapsed/closed configuration). In some embodiments, a given section of vertical wellbore 5 may have a diameter selected from a range of ten (10) inches to thirty (30) inches, plus or minus one inch. In some embodiments, a given section of vertical wellbore 5 may have a diameter selected from a range of twelve (12) inches to thirty (30) inches, plus or minus one inch. In some embodiments, reamer tool 12 (see e.g., FIG. 2) in an open or operational position may be too wide to traverse the relatively narrow diameter vertical wellbore 5. In some embodiments, in a closed position, reamer tool 12 may be lowered through vertical wellbore 5 to the desired depth for reaming out a given human-made cavern 14. The ability to insert reamer tool 12 through a relatively small diameter vertical wellbore 5, negates a need for larger diameter wellbores, from the surface to the desired depth, which would be operationally more difficult, more expensive, and more time-consuming in both materials and equipment. In addition, in a large diameter wellbore, it may be difficult to protect the near surface water-bearing zones or potable water tables for environmental safety since it is easier to “case” or line a smaller diameter wellbore with steel and/or cement than a larger diameter wellbore that may be 6 feet or more in diameter. Larger diameter wellbores are problematic near the surface since larger diameter steel cylinders are structurally weaker and prone to collapse when loaded laterally. For example, and without limiting the scope of the present invention, in some embodiments, multiple initial vertical wellbore sections 5 may be drilled by conventional means from an initial vertical wellbore 5 as lateral wellbores which may have an S-shaped section leading to an additional separate vertical section capable of initiating and implementing the jet drilling equipment for forming a launch chamber 7 therein. See e.g., FIG. 1A and FIG. 3A of U.S. patent application Ser. No. 16/285,199 which show such S-shaped sections of wellbores. Continuing discussing FIG. 1A, in some embodiments, once a given vertical wellbore 5 is formed from terrestrial ground-level 3 to disposal formation rock 15, equipment used to form vertical wellbore 5 may be removed from vertical wellbore 5. In some embodiments, then jet drilling equipment may be inserted and/or landed to a bottom and/or to a distal/terminal portion of vertical wellbore 5 in preparation of jet drilling operations to form a given launch chamber 7 therein. In some embodiments, the jet drilling equipment may comprise at least one jetting tool 10, at least one jet drill fluid pipe 9, a high-pressure conduit 6a, the jet drilling fluid, a supply/reservoir 2a of the jet drill fluid, a pumping means 2b, portions thereof, combinations thereof, and/or the like. Note, see FIG. 1B for jet fluid supply/reservoir 2a and pumping means 2b. In some embodiments, jet fluid supply/reservoir 2a and/or pumping means 2b may be located on and/or proximate to terrestrial ground-level 3. In some embodiments, jet fluid supply/reservoir 2a and pumping means 2b may be operatively connected to each other. In some embodiments, pumping means 2b and high-pressure conduit 6a may be operatively connected to each other. In some embodiments, high-pressure conduit 6a may be at least mostly located in the given vertical wellbore 5 during jet drilling operations. In some embodiments, high-pressure conduit 6a may be have two opposing terminal ends, with one being operatively connected to pumping means 2b and the other being operatively connected to jetting tool 10 and jet drill fluid pipe 9. In some embodiments, high-pressure conduit 6a may be configured for high pressure use. In some embodiments, high-pressure conduit 6a may be a means for moving the jetting fluid therein, while under high pressure, from jet fluid supply/reservoir 2a to jet drill fluid pipe 9. In some embodiments, pumping means 2b may pump the jetting fluid from jet fluid supply/reservoir 2a to jet drill fluid pipe 9, and may do while generating high pressures of the jetting fluid. In some embodiments, jet drill fluid pipe 9 may be at least mostly located within jetting tool 10. In some embodiments, jet drill fluid pipe 9 may have two opposing terminal ends, with one connecting to a terminal end of high-pressure conduit 6a and the other end terminating at a nozzle/orifice of jet drill fluid pipe 9, where the jetting fluid may be ejected a high-pressures into jet flow 11. In some embodiments, the nozzle/orifice of jet drill fluid pipe 9 may be located on an exterior vertical side of jetting tool 10. In some embodiments, the nozzle/orifice of jet drill fluid pipe 9 may be located on an exterior vertical side of jetting tool 10, closer to a bottom of jetting tool 10 than a top of jetting tool 10. In some embodiments, jet flow 11 may be directed at portions of disposal formation rock 15, wherein jet flow 11 may erode, cut, carve, excavate, combinations thereof, and/or the like at least portions of disposal formation rock 15 to form the given launch chamber 7. In some embodiments, the eroded, cut, carved, excavated, portions thereof, combinations thereof, and/or the like of disposal formation rock 15 may be shown as channel jetted 11a in the relevant figures. Continuing discussing FIG. 1A, in some embodiments, a transverse cross-section through a given jetting tool 10 may have a dimension that is the same or smaller than a diameter of vertical wellbore 5, wherein this may facilitate insertion and landing of jetting tool 10 into a bottom of vertical wellbore 5. In some embodiments, a transverse cross-section through a given jetting tool 10 may be substantially circular in shape. In some embodiments, jetting tool 10 may be sized and shaped to be able to rotate/spin while in vertical wellbore 5. Continuing discussing FIG. 1A, in some embodiments, a specialized high-pressure pipe system 6a is implemented internally to the initial vertical wellbore 5 to transport the abrasive jetting fluid from the surface reservoir apparatus 2a down the vertical wellbore 5 to the jet drill tool 10. In some embodiments, jet drill tool 10, which may be a substantially standard industry product, may have an internal section 9, herein referred to jet fluid pipe 9. In some embodiments, jet fluid pipe 9 may be curved to convert the downward vertical flow of the abrasive jetting fluid into a substantially horizontal jet flow 11 (spray) which may be configured to carve out and/or erode a channel jetted 11a as the abrasive jetting fluid 11 impacts portions of the disposal formation rock 15 at very high-pressures. Continuing discussing FIG. 1A, in some embodiments, high-pressure conduit 6a may be selected from one or more of high-pressure jointed pipe, high-pressure coiled tubing, portions thereof, combinations thereof, and/or the like. in some embodiments, high-pressure conduit 6a may be to transport a predetermined/given jetting fluid, with or without abrasives, at relatively high pressures (e.g., about 5,000 psi [pounds per square inch] to about 20,000 psi, plus or minus 1,000 psi). Continuing discussing FIG. 1A, in some embodiments, the jetting fluid that may be ejected from the nozzle/orifice of jetting tool 10/jet drill fluid pipe 9, may be at high-pressures. In some embodiments, the jetting fluid that may be ejected from the nozzle/orifice of jetting tool 10/jet drill fluid pipe 9, may be at predetermined high-pressures. In some embodiments, the jetting fluid may have predetermined properties and/or formulation. In some embodiments, the jetting fluid have abrasive additives included therein. In some embodiments, jet flow 11 may have an exit high-pressure of 5,000 psi (pounds per square inch) to 20,000 psi, plus or minus 1,000 psi. In some embodiments, jet flow 11 may have an exit high-pressure of 20,000 psi. Continuing discussing FIG. 1A, in some embodiments, jetting tool 10 may be operated and varied in a substantially vertical direction (up and/or down) within vertical wellbore 5 to form a predetermined height for the given launch chamber 7 to be formed. In FIG. 1A, reference numeral 10a may indicate an upper position of jetting tool 10 in vertical wellbore 5. In FIG. 1A, reference numeral 10b may indicate a lower position of jetting tool 10 in vertical wellbore 5. In some embodiments, jetting tool 10 may also be rotated around a central longitudinal axis (e.g., around a longitudinal center of vertical wellbore 5 and/or of high-pressure conduit 6a) to help facilitate forming of the given launch chamber 7. See e.g., FIG. 1D. That is, in some embodiments, excavation using jetting tool 10 may occur in a vertical (up/down direction) as well in a radial and horizontal direction to form a given launch chamber 7. In some embodiments, that fully formed launch chamber 7 may be substantially cylindrical in shape with a volume 8. See e.g., FIG. 1A. Continuing FIG. 1A, in some embodiments, jet drill tool 10 may be mechanically capable of moving in one or more planes to allow indexing of jet drill tool 10, which in turn may permit formation of a substantially cylindrical launch chamber 7. For example, and without limiting the scope of the present invention, jet drill tool 10 may be mechanically elevated from location/position 10a to location/position 10b (and/or vice-versa) as shown in the FIG. 1A, to cut a new channel jetted 11a at the new vertical location/position. These indexing/movement processes are discussed further in the discussions of FIG. 1D and FIG. 1E. In some embodiments, below the initial vertical wellbore 5, a given launch chamber 7 may be implemented by the sequential actions of jet drill tool 10, first by indexing in a horizontal plane (e.g., with jet drill tool 10 rotating) and then sequentially in a vertical plane (e.g., with jet drill tool 10 moving up and/or down). This type of horizontal and vertical carving or erosion is similar to the engineering actions used in many other industries and in the prior art, wherein a hollow cavity inside a solid object is implemented using mechanical means by a lathe or by electro-erosion processes, on a much smaller scale. The sequential indexing processes which are later shown in FIG. 1D and FIG. 1E are continued until the designed and/or predetermined dimensions are reached for the given launch chamber 7. In some embodiments, the volume (void) 8 may be with respect to interior volume of the given launch chamber 7. In some embodiments, the pre-determined dimensions of a given launch chamber 7 may be determined by the overall largest operational/open diameter of a given reamer tool 12 that may be desired to be used to form the given human-made cavern 14. In some embodiments, volume 8 of a given launch chamber 7 may have a predetermined diameter that is larger than a largest dimension of the at least one reaming tool 12, when the at least one reaming tool 12 is in an open configuration. In some embodiments, a plurality of channels jetted 11a together may form a given volume 8 of a given launch chamber 7. Continuing discussing FIG. 1A, in some embodiments, volume 8 for a given launch chamber 7 may be predetermined. In some embodiments, volume 8 for a given launch chamber 7 may have a (horizontal) diameter (protruding horizontally into disposal formation rock 15) selected from a range of four (f) feet to ten (10) feet, plus or minus one (1) foot. In some embodiments, volume 8 for a given launch chamber 7 may have a (vertical) height (protruding towards into disposal formation rock 15) selected from a range of six (6) feet to twelve (12) feet, plus or minus one (1) foot. In other embodiments, volume 8 may be other predetermined dimensions. Continuing discussing FIG. 1A, in some embodiments, various surface facilities 2 may be located on terrestrial ground-level 3. In some embodiments, associated usually, at nearby/proximate locations close to the drill rig 1, may be surface facilities 2 for the jet drilling system. In some embodiments, surface facilities 2 may comprise one or more: jet fluid supply/reservoir 2a, pumping means 2b, buildings, structures, sheds, storage areas, staging areas, personnel accommodations, portions thereof, combinations thereof, and/or the like. Note, see FIG. 1B for jet fluid supply/reservoir 2a and pumping means 2b. Continuing discussing FIG. 1A, in some embodiments, vertical wellbore 5 may pass through various near surface formation 4. In some embodiments, disposal formation rock 15 may be located below and/or beneath near surface formation(s) 4. In some embodiments, near surface formation(s) 4 may be disposed between terrestrial ground-level 3 and disposal formation rock 15. In some embodiments, human-made cavern(s) 14 may not be suitable for being located in near surface formation(s) 4 (e.g., because of increased environmental and/or water contamination risks associated with storing waste materials 17 in near surface formation(s) 4). FIG. 1B may show a schematic side view of various components that may be used in some embodiments of the invention with respect to forming a given launch chamber 7, wherein jet drilling may be used to form the given launch chamber 7. FIG. 1B differs from FIG. 1A by FIG. 1B showing jet fluid supply/reservoir 2a and pumping means 2b, both of which are noted above. In some embodiments, pumping means 2b may comprise at least one pump. In some embodiments, pumping means 2b may comprise one or more pumps. In some embodiments, pumping means 2b may comprise two or more pumps. In some embodiments, at least one pump of pumping means 2b may be configured to pump the jetting fluid (which may be abrasive) from jet fluid supply/reservoir 2a, to high-pressure conduit 6a, and to jet drill fluid pipe 9. In some embodiments, most of the jetted fluid expelled from jetting tool 10, may collect inside the growing launch chamber 7 space (volume 8) and accumulate in the lower portion of the growing launch chamber 7 as the jet process continues and jetting tool 10 moves upwards in wellbore 5. This small amount of expelled jetted liquid with formation 15 particulate will not have any undesirable effects of the very high pressure jetted fluid which is being pumped through the jet nozzle(s) of jetting tool 10 to carve out the void in the formation rock 15. In some embodiments, the expelled jet fluid is usually not pumped back to the surface 3. In some embodiments, the expelled jet fluid just remains in the bottom of the launch chamber 7 area and wellbore 5 and may be removed after, if so desired or needed. In some embodiments, the expelled jet fluid will not affect the jetting nor drilling operations. In some embodiments, the launch chamber 7 may be substantially full of drilling mud when the reaming process begins for the human-made cavern 14 construction operations and the big reamer 12 is in operation. In general, all downhole operations may occur with substantially full or nearly liquid filled wellbores/chambers/caverns. However, in some embodiments, at least one pump of pumping means 2b may be configured to pump expelled (effluent) jetting fluid (that has exited jet drill fluid pipe 9 as jet flow 11) back through a portion of jet drill fluid pipe 9, through a portion of high-pressure conduit 6a, and back to terrestrial ground-level 3. In such embodiments, jet drill fluid pipe 9 and/or high-pressure conduit 6a may comprise at least two separate fluid pathways configured for moving fluids, at high-pressures, in substantially opposing directions. In some embodiments, this effluent may also comprise portions of the eroded disposal formation rock 15 (that were eroded by jet flow 11). Continuing discussing FIG. 1B, in some embodiments, a given jetting tool 10 may be connected to at least one high-pressure conduit 6a, wherein the at least one high-pressure conduit 6a may run from the given jetting tool 10 to terrestrial surface 3, with portions of the at least one high-pressure conduit 6a passing through at least one wellbore 5 to pumping means 2b; wherein by use of pumping means 2b, the at least one high-pressure conduit 6a may be configured to transport (and may transport) the jetting fluid, under high-pressure, from jetting fluid reservoir 2a to the given jetting tool 10, wherein jetting fluid reservoir 2a may be operatively connected to the pumping means 2b. In some embodiments, the jetting fluid may comprises at least one abrasive additive, wherein the jetting fluid may be configured to assist with mechanical and/or chemical erosion of regions of a geological formation that come into contact with the jetting fluid when the jetting fluid is under high-pressure. In some embodiments, a given jetting tool may comprise at least one nozzle/orifice that may be configured to deliver/discharge/eject the jetting fluid at high-pressure towards regions of the geological formation resulting in erosion of at least some of those regions of the geological formation. In some embodiments, this geological formation may be axially surrounding bottom/distal/terminal portions of wellbore 5. In some embodiments, this geological formation that a given launch chamber 7 may be formed from and/or where jet drilling operations may be directed to, may be portions of disposal formation rock 15 (deep geological formation). In some embodiments, this geological formation that a given launch chamber 7 may be formed from and/or where jet drilling operations may be directed to, may not be portions of disposal formation rock 15 (deep geological formation), i.e., may be some other formation. Continuing discussing FIG. 1B, in some embodiments, the jetting drilling system may comprise at least one jet drill conduit centralizer 6c. In some embodiments, jet drill conduit centralizer 6c may be configured to assist portions of high-pressure conduit 6a to be positioned substantially centrally within its outer wellbore 5. In some embodiments, disposed around axial side(s) of a portion of high-pressure conduit 6a may be at least one jet drill conduit centralizer 6c. In some embodiments, a given jet drill conduit centralizer 6c may be in operative communication with a portion of high-pressure conduit 6a. In some embodiments, a given jet drill conduit centralizer 6c may be physically touching a portion of high-pressure conduit 6a. In some embodiments, a given jet drill conduit centralizer 6c may be attached to a portion of high-pressure conduit 6a. In some embodiments, a given jet drill conduit centralizer 6c may be disposed between a portion of high-pressure conduit 6a and a portion of proximate wellbore 5. In some embodiments, the reaming system may comprise at least one jet drill conduit centralizer 6c. In some embodiments, jet drill conduit centralizer 6c may be configured to assist portions of drill pipe apparatus 6b to be positioned substantially centrally within its outer wellbore 5. In some embodiments, disposed around axial side(s) of a portion of drill pipe apparatus 6b may be at least one jet drill conduit centralizer 6c. In some embodiments, a given jet drill conduit centralizer 6c may be in operative communication with a portion of drill pipe apparatus 6b. In some embodiments, a given jet drill conduit centralizer 6c may be physically touching a portion of drill pipe apparatus 6b. In some embodiments, a given jet drill conduit centralizer 6c may be attached to a portion of drill pipe apparatus 6b. In some embodiments, a given jet drill conduit centralizer 6c may be disposed between a portion of drill pipe apparatus 6b and a portion of proximate wellbore 5. FIG. 1C may show a schematic side view of distal portions of a jet drilling system used to form a given launch chamber 7. FIG. 1C may show jet flow 11 being expelled at high-pressure from an orifice/nozzle of jet drill fluid pipe 9 of jetting tool 10, to erode a portion of disposal formation rock 15 forming a given channel jetted 11a. In some embodiments, during such jet drilling operations, jetting tool 10 may be moved up and/or down and rotationally (around a central longitudinal axis of vertical wellbore 5 and/or of high-pressure conduit 6a) forming a plurality of channels jetted 11a, wherein this plurality of channels jetted 11a may form volume 8 of a given launch chamber 7, that may be substantially cylindrical in overall shape. In some embodiments, a given channel jetted 11a formed from jet flow 11 may be substantially linear, parallel, colinear, and in linear alignment a longitudinal axis of jet flow 11. In some embodiments, as jetting tool 10 moves up and/or down, channels jetted 11a may be substantially as a vertical planar sheet of void (eroded) space; whereas, as jetting tool 10 moves rotationally, channels jetted 11a may form a substantially horizontal disk/disc of void (eroded) space. These eroded void spaces may form volume 8 of a given launch chamber 7. FIG. 1D may show a top-down schematic view or a transverse-cross-sectional schematic view of/through jetting tool 10 and its horizontal (and rotational) indexed movements, wherein such movements in part may facilitate forming the given launch chamber 7. In some embodiments, by rotationally indexing the jetting tool 10, in a given horizontal plane, around a central longitudinal axis of vertical wellbore 5 and/or of high-pressure conduit 6a, the high-pressure (abrasive) jet flow 11 can be indexed in a rotational and horizontal manner shown via the direction arrow 18. In some embodiments, by repeating this indexing process in a complete 360-degree circle within that given horizontal plane, a substantially horizontal disk/disc of void (eroded) space may be formed in disposal formation rock 15. A height of such a substantially horizontal disk/disc of void (eroded) space may be about a diameter of jet flow 11. FIG. 1E may show a schematic side view of jetting tool 10 and its vertical (up and/or down) indexed movements, wherein such movements in part may facilitate forming the given launch chamber 7. In some embodiments, by vertically indexing jetting tool 10, the high-pressure (abrasive) jet flow 11 may be indexed in a vertical manner shown via the direction arrow 19 to a higher location 10a. In some embodiments, such vertical indexing of jetting tool 10 may occur in a given substantially vertical axis, that in turn may then form a substantially vertical planar sheet of void (eroded) space in disposal formation rock 15. In some embodiments, jetting tool 10 may begin jet drilling at a bottom location of vertical wellbore 5 and may be first indexed rotationally and horizontally according to direction 18 and only after 360 degrees of jet drilling has been completed resulting in formation of a first substantially horizontal disk/disc of void (eroded) space, may jetting tool 10 then be indexed vertically according to direction 19; wherein at this new vertical height a new substantially horizontal disk/disc of void (eroded) space may be formed on top of the prior/first substantially horizontal disk/disc of void (eroded) space; and then once this latest substantially horizontal disk/disc of void (eroded) space may be formed, jetting tool 10 may be indexed vertically again to another new height and yet another substantially horizontal disk/disc of void (eroded) space may be formed; and this process of horizontal/rotational indexing followed by vertical indexing may continue until a full/complete volume 8 may be formed for a given launch chamber 7, wherein volume 8 may be substantially shaped as a hollow cylinder. See e.g., FIG. 1D, FIG. 1E, and FIG. 1A. In some embodiments, the vertical indexing process, jetting tool 10 may always be pulled vertically upwards to maintain tension in the jet drill system, since pushing down on the downhole jet drilling system may be mechanically ineffective. Whereas, in other embodiments, vertical indexing may occur in up or down vertical directions. FIG. 1F may show a schematic side view of a jetting tool 10 with at least two jets, wherein the at least two jets may be vertically stacked with respect to each other. In some embodiments, a distal/terminal portion of jet drill fluid pipe 9 may terminate in at least two different orifices/nozzles, configured to direct and emit two different jet flows 11. In some embodiments, jetting tool 10 may have on its exterior side at least two different orifices/nozzles, configured to direct and emit two different jet flows 11. In some embodiments, the two orifices/nozzles may be fixedly located side by side with each other. In some embodiments, the two orifices/nozzles may be fixedly vertically stacked with respect to each other. In practice operationally higher pump pressures may be needed as a quantity of jet flows 11 may be increased for channel jetted 11a development in disposal formation rock 15. FIG. 1G may show a schematic top view of a jetting tool 10 with at least two jets, wherein the at least jets may be horizontally and oppositely disposed with respect to each other. In some embodiments, a distal/terminal portion of jet drill fluid pipe 9 may terminate in at least two different orifices/nozzles, configured to direct and emit two different jet flows 11. In some embodiments, jetting tool 10 may have on its exterior side at least two different orifices/nozzles, configured to direct and emit two different jet flows 11. In some embodiments, the two orifices/nozzles may be fixedly located on opposing sides of jetting tool 10 with respect to each other. In some embodiments, in a given horizontal plane the two opposing jet flows 11 from the two opposing orifices/nozzles may be erode disposal formation rock 15 in opposite directions from each other. In practice operationally higher pump pressures may be needed as a quantity of jet flows 11 may be increased for channel jetted 11a development in disposal formation rock 15. In some embodiments, the teachings of FIG. 1F and FIG. 1G may be combined providing for a four jet embodiment, wherein the opposing sides of jetting tool 10 each may comprise a pair of vertically stacked orifices/nozzles for jet flows 11. Use of multiple jets may make forming a given launch chamber 7 faster and more efficient. See e.g., FIG. 1F and/or FIG. 1G. FIG. 1H may show a schematic side view of a completed launch chamber 7. Note in FIG. 1H the jet drilling equipment has been removed from launch chamber 7 and its associated (connected) vertical wellbore 5. Launch chamber 7 as shown in FIG. 1H may now be ready to receive a given reamer tool 12 (in a non-deployed/non-expanded configuration). FIG. 2 may show a schematic side view of at least a portion of a reamer tool 12. In some embodiments, reamer tool 12 may be a type of downhole drill device. In some embodiments, reamer tool 12 may be used to enlarge a borehole below a point during well drilling operations. In some embodiments, reamer tool 12 may be strategically positioned either above a drill bit or above a specialized bottom hole assembly run inside an existing borehole (such as vertical wellbore 5). Preexisting reamer tools may be used in existing oil-field drilling operation and may exist in numerous designs and in sizes varying from a few inches to more than 60 inches (in an undeployed configuration) for a given reaming tool. In some embodiments, reamer tool 12 may be substantially similar to such preexisting reamer tools used in oil drill operations. Continuing discussing FIG. 2, reamer tool 12 may be comprised of a body extensible (pivotable) mobile parts and/or cutting devices. In some embodiments, reamer tool 12 may comprise at least one large diameter moveable cutting arm 12a and/or at least one small diameter moveable cutting arm 12b. In some embodiments, the cutting devices may comprise at least one large diameter moveable cutting arm 12a and/or at least one small diameter moveable cutting arm 12b. In some embodiments, the cutting devices, large diameter moveable cutting arm 12a, small diameter moveable cutting arm 12b, may comprise moving parts, arms, blocks, blades, cutters, portions thereof, combinations thereof, and/or the like. In some embodiments, “large” and “small” with respect to large diameter moveable cutting arm 12a and small diameter moveable cutting arm 12b may be with respect to each other. That is, large diameter moveable cutting arm 12a may have larger diameter cutters than small diameter moveable cutting arm 12b. That is, small diameter moveable cutting arm 12b may have smaller diameter cutters than large diameter moveable cutting arm 12a. Continuing discussing FIG. 2, in some embodiments, reamer tool 12 may have three such cutting devices of large diameter moveable cutting arm 12a and small diameter moveable cutting arm 12b. Continuing discussing FIG. 2, in some embodiments, these cutting devices, large diameter moveable cutting arm 12a and small diameter moveable cutting arm 12b, may exist in two main configurations, an open configuration and a closed configuration. In some embodiments, a body of reamer tool 12 may comprise expandable and retractable cutting arm(s) 13. In some embodiments, expandable and retractable cutting arm(s) 13 may comprise large diameter moveable cutting arm 12a and/or small diameter moveable cutting arm 12b. In some embodiments, reamer tool 12 may exist in the two main configurations, the open configuration and the closed configuration. FIG. 2 may show both configurations simultaneously; however, in reality reamer tool 12 would only exist one or the other configuration, i.e., the two configurations are mutually exclusive. In some embodiments, the closed configuration may be for moving/transporting reamer tool 12 within confined spaces; whereas, the open configuration may be for active under-reaming operations to enlarge confined spaces. In some embodiments, reamer tool 12 may be transition from the closed configuration to the open configuration; and/or may transition from the open configuration to the closed configuration. Continuing discussing FIG. 2, in some embodiments, in the closed configuration, the cutting devices, large diameter moveable cutting arm 12a and small diameter moveable cutting arm 12b, may be substantially retracted to the body of reamer tool 12, which in turn may provide for an overall smaller diameter of reamer tool 12 while in this closed configuration. In some embodiments, this closed configuration of reamer tool 12 may be used during descent (or ascent) into a given wellbore, such as vertical wellbore 5. In some embodiments, an overall diameter of reamer tool 12, when reamer tool 12 may be in the closed configuration, may be sized/dimensioned to fit within a diameter of vertical wellbore 5. In some embodiments, the closed configuration of reamer tool 12 may be useful for moving reamer tool 12 within a given wellbore (e.g., vertical wellbore 5). For example, and without limiting the scope of the present invention, with reamer tool 12 in the closed configuration, reamer tool 12 may be moved into a desired location within a given wellbore (e.g., vertical wellbore 5) and/or within a formed launch chamber 7, where under-reaming operations are to occur. For example, and without limiting the scope of the present invention, with reamer tool 12 in the closed configuration, reamer tool 12 may be moved into a formed launch chamber 7 where reamer tool 12 may now have sufficient room to extend and/or deploy into its open configuration. For example, and without limiting the scope of the present invention, with reamer tool 12 in the closed configuration, reamer tool 12 may be removed from a location within a given wellbore (e.g., vertical wellbore 5), from a launch chamber 7, and/or from a human-made cavern 14) where under-reaming operations have already occurred. Continuing discussing FIG. 2, in some embodiments, reamer tool 12 may transition from its closed configuration to its open configuration, by at least one predetermined input. In some embodiments, the at least one predetermined input may be one or more of: a received optical signal; a received electronic signal; a received electromagnetic signal; a received mechanical input; a received fluid pressure input; portions thereof; combinations thereof; and/or the like. In some embodiments, the received electromagnetic signal may be from a RFID (radio frequency identification) tag that may be proximate to reamer tool 12. In some embodiments, energy and/or power for opening into the open configuration and/or for operating once in the open configuration may come from hydraulic pressure supplied to the given reamer tool 12, via drill pipe apparatus 6b, and from surface located pumping means 2b and/or the like. In some embodiments, the under-reaming system may be activated by a pre-programmed RFID tag, sent down the wellbore to the reamer apparatus to trigger reamer activity via a reamer control module which may energize the reamer's the cutter system. Note, the reaming technology is such that today (2020) multiple reamers may be run in tandem and they may be independently controlled to allow rapid and efficient under-reaming of disposal formation rock 15 up to a prescribed (predetermined) designed diameter to form a given human-made cavern 14. In some embodiments, reamer tool 12 may be connected to one or more drill strings. In some embodiments, reamer tool 12 may be connected to one or more drill pipe apparatus 6b (a portion of which may be a drill string). In some embodiments, drill pipe apparatus 6b may be used to move a given attached reamer tool 12 vertically up and/or down. FIG. 3A may show a schematic side view of a formed launch chamber 7, wherein reamer tool 12 has been inserted/positioned/located therein. Aspects of the launch chamber 7, including its formation, are discussed above in the discussions of FIG. 1A through FIG. 1H. Aspects of reamer tool 12 are discussed above in the discussion of FIG. 2. In some embodiments, moving and/or locating a given reamer tool 12 into a formed launch chamber 7, may be done by moving reamer tool 12 in its closed configuration through vertical wellbore 5 (that is attached to launch chamber 7) until reaching launch chamber 7. FIG. 3A presumes launch chamber 7 has been previously formed (e.g., according to FIG. 1A through FIG. 1H) and that the jet drilling equipment has been removed from vertical wellbore 5 and its attached launch chamber 7. In some embodiments, moving and/or locating a given reamer tool 12 into a formed launch chamber 7, may then provide sufficient space for reamer tool 12 to transition between closed configuration and the open configuration; and/or vice versa. In some embodiments, volume 8 (of launch chamber 7) may be larger than a greatest transverse/horizontal dimension of reamer tool 12 in its open configuration. Continuing discussing FIG. 3A, in some embodiments, reaming tool 12 may be connected to the surface equipment on rig 1 by drill pipe tubulars 6b. In some embodiments, drill pipe tubulars 6b may include oil industry-standard drilling tubulars and/or heavy weight drill collars. In some drilling situations the reaming tool 12 may be connected to a down hole unit which may comprise a downhole motor and geo-steering systems, wherein such equipment may be standard and well understood in the oil drilling industry today [2020]. FIG. 3B may show a schematic side view of a formed launch chamber 7 and at least a portion of a given human-made cavern 14, wherein reamer tool 12 may be operating (e.g., under-reaming) to form that given human-made cavern 14. In some embodiments, reamer tool 12 may have been deployed/extended into its open configuration in launch chamber 7 and then under-reaming operations may have begun directed at a bottom of launch chamber 7 to begin forming the given human-made cavern 14. FIG. 3B may show the reamer tool 12, in its open configuration, under-reaming and forming the given human-made cavern 14. In some embodiments, during the under-reaming operations for forming a given human-made cavern 14, the expandable and retractable cutting arm 13, large diameter moveable cutting arm 12a, and/or small diameter moveable cutting arm 12b may be moving at least partially in a direction of movement 16. In some embodiments, direction of movement 16 may be substantially up and/or down movement. FIG. 3C may show a schematic side view of a formed launch chamber 7 and a formed human-made cavern 14, wherein reamer tool 12 may have formed that given human-made cavern 14. In some embodiments, a given human-made cavern 14 may be located vertically below a given launch chamber 7. In some embodiments, a bottom of a given launch chamber 7 may transition into a top of a given human-made cavern 14. In some embodiments, an open bottom of a given launch chamber 7 may transition into an open top of a given human-made cavern 14. In some embodiments, a given launch chamber 7 may be attached to a given human-made cavern 14. In some embodiments, a pair of attached launch chamber 7 and human-made cavern 14 may share a common longitudinal axis. In some embodiments, a diameter of human-made cavern 14 may be the same or less than a diameter of launch chamber 7. Continuing discussing FIG. 3C, in some embodiments, human-made cavern 14 may be reamed out to its desired dimensions up to about 10,000 feet plus or minus 1,000 feet in vertical length (e.g., extending down into disposal formation rock 15); and/or up to 10 feet in diameter plus or minus one (1) foot (e.g., extending horizontally out into disposal formation rock 15). In some embodiments, a given human-made cavern 14 may have a fixed diameter that is selected from a range of three (3) feet to ten (10) feet, plus or minus one (1) foot. In some embodiments, a given human-made cavern 14 may have a fixed diameter that is selected from a range of three (3) feet to ten (10) feet, plus or minus six (6) inches. In some embodiments, a given human-made cavern 14 may have a fixed length that extends into the deep geological formation 15, wherein the fixed length is selected from a range of 1,000 feet to 10,000 feet, plus or minus one hundred (100) feet. In some embodiments, a given human-made cavern 14 may be substantially surrounded by a given deep geological formation 15. At a termination of the reaming process, reaming tool 12 may be transitioned into its closed configuration and pulled back to terrestrial surface-level 3 using drill pipe apparatus/tubulars 6b (e.g., drill string(s)) through human-made cavern 14, launch chamber 7, and/or the attached vertical wellbore 5. With respect to FIG. 3C, now that the given human-made cavern 14 has been formed, reamer tool 12 may be transitioned back into its closed configuration and removed from human-made cavern 14, launch chamber 7, and its attached vertical wellbore 5. Once reamer tool 12 has been so fully removed, human-made cavern 14 may be pretreated/preconditioned for receiving waste material(s) 17; and/or waste material(s) 17 may be added to human-made cavern 14 for long-term disposal and/or storage therein, see e.g., FIG. 4. FIG. 4 may show a schematic side view of a formed launch chamber 7 and a formed human-made cavern 14, wherein waste material(s) 17 may now be loaded into that formed human-made cavern 14. In some embodiments, prior to loading waste material(s) 17 into human-made cavern 14, human-made cavern 14 may be pretreated/preconditioned for receiving waste material(s) 17 (e.g., with coatings, sprays, paints, portions thereof, combinations thereof, and/or the like). In some embodiments, loading of waste material(s) 17 into human-made cavern 14 may be facilitated by one or more of drilling rig 1, surface facilities 2, pumping means 2b, portions thereof, combinations thereof, and/or the like. In some embodiments, for waste material(s) 17 to reach human-made cavern 14, waste material(s) 17 may pass through vertical wellbore 5. In some embodiments, at least some portions of vertical wellbore 5 may be lined with casing(s), pipes, cement, portions thereof, combinations thereof, and/or the like. Continuing discussing FIG. 4, in some embodiments, vertical wellbore 5 may be attached to and in fluid communication with launch chamber 7 and with terrestrial surface-level 3. In some embodiments, launch chamber 7 may be attached to and in fluid communication with vertical wellbore 5 and with human-made cavern 14. In some embodiments, human-made cavern 14 may be attached to and in fluid communication with launch chamber 7. Continuing discussing FIG. 4, in some embodiments, after a given human-made cavern 14 may have been filled with waste material(s) 17 to a predetermined level/quantity, human-made cavern 14, launch chamber 7, vertical wellbore 5, portions thereof, combinations thereof, and/or the like, may be at least partially sealed/closed (e.g., with cement plugs and/or the like). In some embodiments, after a given human-made cavern 14 may have been filled with waste material(s) 17 to a predetermined level/quantity, human-made cavern 14, launch chamber 7, vertical wellbore 5, portions thereof, combinations thereof, and/or the like, may be completely sealed/closed (e.g., with cement plugs and/or the like). Continuing discussing FIG. 4, in some embodiments, prior to sealing/closing human-made cavern 14, launch chamber 7, and/or vertical wellbore 5, a protective medium blanket may be inserted into human-made cavern 14. In some embodiments, this protective medium blanket may be substantially on top of waste material(s) 17 within human-made cavern 14. FIG. 5 may show a flow chart summarizing how three methods (phases) described herein may relate and/or interact with each other. FIG. 5 may show a flow chart summarizing how method 600 (phase 1) flows into method 700 (phase 2) and how method 700 flows into method 800 (phase 3). In some embodiments, method 600 may be a method of forming the initial/pilot vertical wellbore 5, see e.g., FIG. 1A to FIG. 4 and see FIG. 6. In some embodiments, method 700 may be a method of jet drilling to form a given launch chamber 7 at a bottom of the vertical wellbore 5, see e.g., FIG. 1A to FIG. 1H and see FIG. 7. In some embodiments, method 800 may be a method of forming a given human-made cavern 14 and/or of using that formed human-made cavern 14 for the long-term disposal and/or storage of waste-material(s) 17, see e.g., FIG. 3A to FIG. 4 and see FIG. 8. Continuing discussing FIG. 5, in some embodiments, with respect to a single human-made cavern 14 to be formed, method 600 (phase 1) may come first and upon completion, method 600 may transition into method 700 (phase 2); wherein upon completion of method 700, method 700 may transition into method 800 (phase 3); wherein method 800 may then be executed. FIG. 6 may show at least some steps in a method 600 for forming an initial vertical (pilot) wellbore 5. In some embodiments, method 600 may be considered phase 1 of the operations. In some embodiments, method 600 may be a method of locating and drilling with standard rotary drilling tools, an initial/pilot substantially vertical wellbore 5 from terrestrial surface-level 3 to a predetermined/designed depth, for eventual formation of a given launch chamber 7. In some embodiments, method 600 may comprise one or more steps of: 601, 603, 605, 607, and/or 609. In some embodiments, some steps of method 600 may occur in non-numeral order with respect to step reference numerals. In some embodiments, at least one six hundred series steps may be omitted from method 600. Continuing discussing FIG. 6, in some embodiments, step 601 may be a step of one or more of: locating at least one site for wellbore 5 drilling; selecting at least one site for wellbore 5 drilling; setting up drilling rig 1 for wellbore 5 drilling at the at least one site; preparing for drilling operations at the at least one site; portions thereof; combinations thereof; and/or the like. In some embodiments, the site may need to be located substantially vertically above at least one disposal formation rock 15. In some embodiments, completion of step 601 may cause method 600 to transition into step 603. In some embodiments, completion of step 601 may cause method 600 to transition into step 605. Continuing discussing FIG. 6, in some embodiments, step 603 may be a step of one or more of: preparing/installing surface facilities 2 for drilling and/or reaming operations; preparing/installing jet fluid supply (reservoir) 2a; preparing/installing pumping means 2b; preparing for drilling operations; preparing for jet drilling operations; portions thereof; combinations thereof; and/or the like. In some embodiments, completion of step 603 may cause method 600 to transition into step 605. In some embodiments, step 603 may occur after step 605. In some embodiments, completion of step 603 may cause method 600 to transition into step 607, if step 605 has already occurred. Continuing discussing FIG. 6, in some embodiments, step 605 may be a step of drilling at least one substantially vertical pilot wellbore 5, using drilling rig 1, at the at least one site, that is located substantially vertically above at least one disposal formation rock 15. In some embodiments, step 605 may be drilling at least one substantially vertical pilot wellbore 5 to a predetermined depth. In some embodiments, step 605 may be drilling at least one substantially vertical pilot wellbore 5 to disposal formation rock 15. In some embodiments, step 605 may be drilling at least one substantially vertical pilot wellbore 5 into disposal formation rock 15. In some embodiments, the at least one substantially vertical wellbore 5 may have a diameter from ten (10) inches to thirty (30) inches plus or minus one inch; and a vertical depth between 2,000 feet and 25,000 feet, plus or minus 100 feet. In some embodiments, step 605 may utilize at least one rotary drill and/or drill pipe apparatus/tubulars 6b connected to the at least one rotary drill. In some embodiments, completion of step 605 may cause method 600 to transition into step 607. Continuing discussing FIG. 6, in some embodiments, step 607 may be a step of one or more of: removing drilling equipment used to form the at least one substantially vertical pilot wellbore 5 from the at least one substantially vertical pilot wellbore 5; deploying jet drilling equipment (e.g., jetting tool 10, jet drill fluid pipe 9, and/or at least a portion of high-pressure conduit 6a) for jet drilling operation in a predetermined location within the at least one substantially vertical pilot wellbore 5; portions thereof; combinations thereof; and/or the like. In some embodiments, step 607 may comprise removing rotary drilling equipment from the at least one substantially vertical pilot wellbore 5. In some embodiments, step 607 may comprise removing drill pipe apparatus/tubulars 6b from the at least one substantially vertical pilot wellbore 5. In some embodiments, step 607 may comprise connecting jetting tool 10 to pumping means 2b and to jet fluid supply (reservoir) 2a via high-pressure conduit 6a. In some embodiments, completion of step 607 may cause method 600 to transition into step 609. Continuing discussing FIG. 6, in some embodiments, step 609 may be a step of landing and/or fixing applicable/relevant jet drilling equipment (e.g., jetting tool 10, jet drill fluid pipe 9, and/or at least a portion of high-pressure conduit 6a) at the predetermined location (and/or portions leading up to the predetermined location) within the at least one substantially vertical pilot wellbore 5. In some embodiments, the predetermined location may be at a bottom of the at least one substantially vertical pilot wellbore 5. In some embodiments, the predetermined location may be at a distal/terminal portion of the at least one substantially vertical pilot wellbore 5. In some embodiments, completion of step 609 may cause method 600 to transition to method 700. In some embodiments, completion of step 609 may cause method 600 to transition to step 703. FIG. 7 may show at least some steps in a method 700 for forming a given launch chamber 7. For a given well site and/or for a given substantially vertical 5, method 700 may follow completion of method 600. In some embodiments, method 700 may be considered phase 2 of operations. In some embodiments, method 700 may be a method of jet drilling, eroding, and/or carving out a launch chamber 7 in disposal formation rock 15 with a specialized jet drilling equipment, that may comprise one or more of: jetting tool 10, jet drill fluid pipe 9, high-pressure conduit 6a, jet fluid supply (reservoir) 2a, pumping means 2b, the jetting fluid itself, portions thereof, combinations thereof, and/or the like. In some embodiments, method 700 may comprise one or more steps of: 701, 703, 705, 707, 709, 711, 713, 715, 717, and/or 719. In some embodiments, some steps of method 700 may occur in non-numeral order with respect to step reference numerals. In some embodiments, at least one seven hundred series steps may be omitted from method 700. Continuing discussing FIG. 7, in some embodiments, step 701 may be a step of preparing jetting tool 10 for jet drilling operation at the predetermined location within the at least one substantially vertical wellbore 5. In some embodiments, step 701 may be a step of fixing jetting tool 10 (for jet drilling operation) in place at the predetermined location within the at least one substantially vertical wellbore 5. In some embodiments, in step 701 jetting tool 10 may be deployed from the terrestrial surface-level 3 via the substantially vertical wellbore 5 to its designated vertical position, such as position 10b at the bottom of the substantially vertical wellbore 5; wherein once there, jetting tool 10 may be fixed in place such that jet fluid 11 may be directed at disposal formation rock 15 after traversing the internal curved pipe section of jet drill fluid pipe 9 which may convert the vertical jetting fluid flow to horizontal jet flow for cutting channels jetted 11a in disposal formation rock 15 on impact. In some embodiments, completion of step 701 may cause method 700 to transition into step 703. Continuing discussing FIG. 7, in some embodiments, step 703 may be a step of initiating jet drilling operations at the predetermined location within the at least one substantially vertical wellbore 5. In some embodiments, in step 703 the jet drilling process may be initiated by pumping abrasive fluids from the surface facility 2 (e.g., jet fluid supply (reservoir) 2a), via the high-pressure conduit 6a using pumping means 2b and thus delivering the subject jetting fluid to jetting tool 10. In some embodiments, the jetting fluid may be pumped from jet fluid supply (reservoir) 2a, by pumping means 2b, through high-pressure conduit 6a and jet drill fluid pipe 9, to be ejected from an orifice/nozzle in jetting tool 10. In some embodiments, completion of step 703 may cause method 700 to transition into step 705. Continuing discussing FIG. 7, in some embodiments, step 705 may be a step of positioning jetting tool 10 within the predetermined location within the at least one substantially vertical wellbore 5 for jet drilling operations into disposal formation rock 15. In some embodiments, step 705 may be a step of jet drilling, carving out an initial channel jetted 11a, in disposal formation rock 15. In some embodiments, the jetting fluid may be pumped from jet fluid supply (reservoir) 2a, by pumping means 2b, through high-pressure conduit 6a and jet drill fluid pipe 9, to be ejected from an orifice/nozzle in jetting tool 10 as jet flow 11 to form an initial channel jetted 11a in disposal formation rock 15. In some embodiments, step 705 may result in at least an initial channel jetted 11a in disposal formation rock 15. In some embodiments, initial channel jetted 11a may be extend substantially linearly into disposal formation rock 15. In some embodiments, completion of step 705 may cause method 700 to transition into step 707. Continuing discussing FIG. 7, in some embodiments, step 707 may be a step of continued jet drilling until a channel jetted 11a into disposal formation rock 15 is carved out to a sufficient (predetermined) length into disposal formation rock 15. In some embodiments, step 707 may be a step of controlling the continued jet drilling until a channel jetted 11a into disposal formation rock 15 is carved out to a sufficient (predetermined) length into disposal formation rock 15. In some embodiments, in step 707 pressure of jet flow 11 may be varied to achieve channel jetted 11a of a sufficient length into disposal formation rock 15. In some embodiments, in step 707 jetting time of jet flow 11 may be varied to achieve channel jetted 11a of a sufficient length into disposal formation rock 15. In some embodiments, in step 707 a composition of the jetting fluid (e.g., abrasive additives mix) may be varied to achieve channel jetted 11a of a sufficient length into disposal formation rock 15. In some embodiments, completion of step 707 may cause method 700 to transition into step 709. Continuing discussing FIG. 7, in some embodiments, step 709 may be a step of jet drilling after a rotationally indexed movement of jetting tool 10, within a given (substantially) horizontal plane. In some embodiments, each rotational indexed movement of jetting tool 10, within the given (substantially) horizontal plane, may be selected from a range of one (1) degree to ten (10) degrees, plus or minus one half (0.5) degree. In this new azimuth position, the jetting process is re-initiated and a new channel jetted 11a is carved out in disposal formation rock 15. See e.g., FIG. 1D and its discussion for such rotational indexing. In some embodiments, completion of step 709 may cause method 700 to transition into step 711. Continuing discussing FIG. 7, in some embodiments, step 711 may be a step of continued jet drilling with rotational indexing and movement of jetting tool 10, carving out a disk/disc/circle of void space at a given height/depth, in disposal formation rock 15. In some embodiments, step 709 may entail rotational indexing of jetting tool 10 and forming a new channel jetted 11a after each indexed rotational move, wherein such rotational indexing and jet drilling may continue until jetting tool 10 has been rotationally indexed for about 360 degrees, resulting in forming a region of void space that is substantially circular in shape. In some embodiments, step 709 may entail rotational indexing of jetting tool 10 and forming a new channel jetted 11a after each indexed rotational move, wherein such rotational indexing and jet drilling may continue until all those carved channels jetted 11a now form a region of void space that is substantially circular in shape. See e.g., FIG. 1D and its discussion for such rotational indexing. In some embodiments, if the jet drilling system is sufficiently robust and sophisticated and disposal formation rock 15 is of suitable petrophysical and rock properties, this horizontal and rotational indexing process may be a substantially continuous process such that the indexing is continuously performed until the full circular void shaped may be carved out, at that particular horizontal plane height/position. In some embodiments, completion of step 711 may cause method 700 to transition into step 713. Continuing discussing FIG. 7, in some embodiments, step 713 may be a step of vertically indexed movement of jetting tool 10, within a given (substantially) vertical plane. In some embodiments, each vertical indexed movement of jetting tool 10, within the given (substantially) vertical plane, may be substantially vertically upwards movement of jetting tool 10. In some embodiments, jetting tool 10 may be moved vertically upwards by an amount selected from a range of one (1) inch to six (6) inches, plus or minus one half (0.5) inch for each such vertically indexed upwards movements. It is noted that vertical indexing as shown in FIG. 1E may be implemented from a lower depth position 10b to a higher depth position 10a. See e.g., FIG. 1E and its discussion for such vertical indexing. In some embodiments, completion of step 713 may cause method 700 to transition into step 715. Continuing discussing FIG. 7, in some embodiments, step 715 may be a step of repeating steps 707 through 711 at the latest vertically indexed height/position of jetting tool 10, so that a new substantially circle shaped region of void space is formed in disposal formation rock 15 at that latest height/position of jetting tool 10. In some embodiments, after steps 707 through 711 are completed for the given level/height of jetting tool 10, step 715 may further comprise repeating step 713 to raise jetting tool 10 to yet another vertically upwards indexed position/height. That is, step 715 may be iterative in nature and may result in a region of void space in disposal formation rock 15 that may be substantially cylindrical in shape. That is, step 715 may be iterative in nature and may result in a region of void space in disposal formation rock 15 that may be launch chamber 7 and/or volume 8. In some embodiments, before vertical indexing to a new height and then carving out a new circle of void space, step 715 may progress to step 717. In some embodiments, completion of step 715 may cause method 700 to transition into step 717. Continuing discussing FIG. 7, in some embodiments, step 717 may be a step of checking whether prior jet drilling operational steps (e.g., steps 707-715) have resulted in a void space in disposal formation rock 15 that substantially matches with a predetermined dimensional size of the launch chamber 7 being built by method 700. In some embodiments, step 717 may be a step of checking whether prior jet drilling operational steps (e.g., steps 707-715) have resulted in a void space in disposal formation rock 15 that substantially matches with a predetermined vertical size dimension of the launch chamber 7 being built by method 700. In some embodiments, with respect to step 717, if the carved void space from jetting operations substantially matches the predetermined dimensional size of launch chamber 7 and/or of volume 8, then the desired launch chamber 7 and/or of volume 8 may be completed and/or formed by method 700. In some embodiments, with respect to step 717, if the carved void space from jetting operations substantially matches the predetermined dimensional size of launch chamber 7 and/or of volume 8, then step 717 may progress into step 719. In some embodiments, with respect to step 717, if the carved void space from jetting operations substantially matches the predetermined dimensional size of launch chamber 7 and/or of volume 8, then step 717 may progress into step 721. With respect to step 717 progressing to step 721 and not step 719, progression from step 717 to step 721, may occur when not further finishing actions are needed nor desired for launch chamber 7 and/or volume 8; whereas, if some finishing actions are needed or desired with respect to launch chamber 7 and/or volume 8, then step 717 may progress to step 719. In some embodiments, with respect to step 717, if the carved void space from jetting operations does not substantially match the predetermined dimensional size of launch chamber 7 and/or of volume 8, then step 717 may progress back to step 713. Continuing discussing FIG. 7, in some embodiments, step 719 may be a step of finishing/completing a given launch chamber 7 and/or volume 8. In some embodiments, step 719 may entail some jet drilling operations within launch chamber 7 to make sure the predetermined dimensions of launch chamber 7 and/or volume 8 are at least met, i.e., rough spots and/or harder/denser projections into launch chamber 7 and/or volume 8 may be removed with some additional jet drilling operations. In some embodiments, launch chamber 7 and/or volume 8 may be complete when a given reaming tool 12 may be lowered into launch chamber 7 and/or volume 8 and that given reaming tool 12 may articulated from its closed configuration to its open configuration and vice versa without obstructions from rock walls of launch chamber 7 and/or volume 8. In some embodiments, completion of step 719 may cause method 700 to transition into step 721. Continuing discussing FIG. 7, in some embodiments, step 721 may be a step of retrieving the jetting drilling equipment from the newly formed launch chamber 7, volume 8, substantially vertical wellbore 5, portions thereof, combinations thereof, and/or the like. In some embodiments, step 721 may be a step of retrieving jetting tool 10, jet drill fluid pipe 9, and/or high-pressure conduit 6a from the newly formed launch chamber 7, volume 8, substantially vertical wellbore 5, portions thereof, combinations thereof, and/or the like. In some embodiments, completion of step 721 may cause method 700 to transition to method 800. In some embodiments, the jet drilling operations of method 700 may be executed substantially continuously until a given horizontal circular void shape may be carved out from disposal formation rock 15 at a given depth in disposal formation rock 15. In some embodiments, the jet drilling operations of method 700 may be executed by rotating and elevating the jetting tool 10 in substantially continuous incremental motions, in a “rotate and elevate” fashion until the given launch chamber 7 may be formed. FIG. 8 may show at least some steps in a method 800 for forming a human-made cavern 14 and/or then using that human-made cavern 14 as disposal location for waste material(s) 17. In some embodiments, method 800 may be considered phase 3 of operations. In some embodiments, method 800 may be a method of large diameter reaming to construct a human-made cavern 14 for waste material(s) 17 disposal/storage using industry type rotary under-reaming equipment. In some embodiments, method 800 may comprise one or more steps of: 801, 803, 805, 807, 809, 811, and/or 813. In some embodiments, some steps of method 800 may occur in non-numeral order with respect to step reference numerals. In some embodiments, at least one seven hundred series steps may be omitted from method 800. Continuing discussing FIG. 8, in some embodiments, step 801 may be a step of deploying, placing, locating, and/or landing a given reaming tool 12 into a volume 8 of a given launch chamber 7. In order to accomplish this, reaming tool 12 may be in its substantially closed configuration, wherein reaming tool 12 may be located into wellbore 5 that connects to launch chamber 7, then using drilling rig 1 and drill pipe apparatus 6b, reaming tool 12 may be lowered down into launch chamber 7 through that connecting wellbore 5. In some embodiments, completion of step 801 may cause method 800 to transition into step 803. Continuing discussing FIG. 8, in some embodiments, step 803 may be a step of expanding/opening reaming tool 12 into its substantially open configuration. In some embodiments, this expansion process may involve movement of the closed arms 12a in an outward direction (e.g., outward direction 16) which may result in cutting arms 13 shown in FIG. 2 and in FIG. 3B to be extended to their fullest extent. In some embodiments, completion of step 803 may cause method 800 to transition into step 805. Continuing discussing FIG. 8, in some embodiments, step 805 may be a step of under-reaming out portions of disposal formation rock 15, using reaming tool 12 in its fully open configuration, to a predetermined depth vertically below launch chamber 7 to form the given human-made cavern 14. In some embodiments, a given human-made cavern 14 size may be from 1,000 feet to 10,000 feet or more in a vertical linear direction. In some embodiments, completion of step 805 may cause method 800 to transition into step 807. Continuing discussing FIG. 8, in some embodiments, step 807 may be a step of retrieving the reaming equipment out from human-made cavern 14, launch chamber 7, the connected wellbore 5, portions thereof, combinations thereof, and/or the like. In some embodiments, step 807 may be a step of retrieving reaming tool 12 and/or drill pipe apparatus/tubulars 6b portions out from human-made cavern 14, launch chamber 7, the connected wellbore 5, portions thereof, combinations thereof, and/or the like. In some embodiments, in order to accomplish such retrieval, reaming tool 12 may be first stopped and then collapsed into its substantially/fully closed configuration. In some embodiments, completion of step 807 may cause method 800 to transition into step 809. In some embodiments, completion of step 807 may cause method 800 to transition into step 811. Continuing discussing FIG. 8, in some embodiments, step 809 may be a step of conditioning and/treating at least some interior surfaces of a given human-made cavern 14 before that 14 receives waste material(s) 17. In some embodiments, this may entail, applying, lining, spraying, painting, at least some interior surfaces of a given human-made cavern 14 with one or more predetermined treatments/conditioners. In some embodiments, step 809 may entail lining at least some interior portion of a given wellbore 5 that connects to a given human-made cavern 14, wherein this lining may be of piping, steel, cement, portions thereof, combinations thereof, and/or the like. In some embodiments, completion of step 809 may cause method 800 to transition into step 811. Continuing discussing FIG. 8, in some embodiments, step 811 may be a step of loading at least some quantity of waste material(s) 17 into a given human-made cavern 14. In some embodiments, step 811 may be facilitated by using drilling rig 1 (or the like) and pumping means 2b (or the like) to pump and/or transport the at least some quantity of waste material(s) 17 through connected wellbore 5 and into human-made cavern 14. In some embodiments, drilling rig 1 (or the like) may have radiation shielding installed thereon. In some embodiments, completion of step 811 may cause method 800 to transition into step 813. Continuing discussing FIG. 8, in some embodiments, step 813 may be a step of stopping/ending method 800. In some embodiments, step 813 may entail closing and/or sealing at least some portion of human-made cavern 14, launch chamber 7, connected wellbore 5, portions thereof, combinations thereof, and/or the like, with one or more plugs. In some embodiments, the one or more plugs may be substantially constructed from a predetermined concrete and/or cement. Some embodiments of the present invention may be characterized as a method for disposing of waste 17 within at least one human-made cavern 14. In some embodiments, such a method may comprise steps of: step (a); step (b); step (c); step (d); step (e); and step (f); wherein these steps are noted below. In some embodiments, the step (a) may be a step of drilling at least one wellbore 5 from a drill site located on a terrestrial surface 3, wherein the at least one wellbore may be substantially vertical and drilled out to at least a predetermined depth. See e.g., method 600, such as step 605. In some embodiments, the step (a) may be at least partially accomplished by using at least one drilling rig 1 located on the terrestrial surface 3 and using rotary oilwell drilling equipment, wherein at least a portion of the rotary oilwell drilling equipment may be operatively connected to the at least one drilling rig 1. See e.g., method 600. In some embodiments, the predetermined depth may be at least to a top boundary of the deep geological formation 15, wherein the deep geological formation 15 may be located substantially vertically below the drill site. In some embodiments, this drilling of the step (a) may be at least partially into the deep geological formation 15. See e.g., method 600. In some embodiments, the step (b) may be a step of inserting at least one jetting tool 10 within the at least one wellbore 5 to a predetermined location. See e.g., method 700, such as step 701. In some embodiments, the predetermined location within the at least one wellbore 5 may be at a distal bottom of the at least one wellbore 5, disposed away from the drill site. In some embodiments, the step (c) may be a step of jet drilling into a geological formation that axially surrounds a portion of the at least one wellbore 5 using the at least one jetting tool 10 to form a launch chamber 7 of a volume 8 of void space within the geological formation. See e.g., method 700, such as steps 707 to 715. In some embodiments, the step (c) may be done by rotational indexing and by vertical indexing of the at least one jetting tool 10 within the at least one wellbore 5; wherein the rotational indexing at a horizontal location within the at least one wellbore 5 may result in formation of a void region that is substantially circular and horizontal (see e.g., method 700, such as steps 709 and 711); wherein the vertical indexing raises the at least one jetting tool to a different vertical location within the at least one wellbore 5 (see e.g., method 700, such as steps 709 and 711). In some embodiments, the geological formation (that axially surround bottom/distal/terminal portions of wellbore 5 and/or that axially surrounds a given launch chamber 7) and the deep geological formation 15 may be a same formation. In some embodiments, the geological formation (that axially surround bottom/distal/terminal portions of wellbore 5 and/or that axially surrounds a given launch chamber 7) and the deep geological formation 15 may not be a same formation. In some embodiments, volume 8 of a given launch chamber 7 may have a predetermined diameter that is larger than a largest dimension of the at least one reaming tool 12, when the at least one reaming tool 12 is in an open configuration. In some embodiments, prior to the step (d), the method may comprise a step of removing the at least one jetting tool 10 from the launch chamber 7 and from the at least one wellbore 5. See e.g., method 700, such as step 719. In some embodiments, the step (d) may be a step of landing at least one reaming tool 12 within the launch chamber 7. See e.g., method 800, such as step 801. In some embodiments, the step (d) may occur while the at least one reaming tool 12 may be in a closed configuration having a smaller diameter that is smaller than a larger diameter of the at least one reaming tool 12 when the at least one reaming tool is in an open configuration. See e.g., method 800, such as step 801. In some embodiments, after the step (d) but before the step (e), the at least one reamer tool 12 may be transitioned from a closed configuration to an open configuration. See e.g., method 800, such as step 803. In some embodiments, the step (e) may be a step of reaming portions of a deep geological formation 15 that are located below the launch chamber 7 to form the at least one human-made cavern 14. See e.g., method 800, such as step 805. In some embodiments, the step (f) may be a step of inserting at least some of the waste 17 into the at least one human-made cavern 14. See e.g., method 800, such as step 811. In some embodiments, prior to the step (f), the method may comprise a step of removing the at least one reaming tool from 12: the at least one human-made cavern 14, the launch chamber 7, and the at least one wellbore 5. See e.g., method 800, such as step 807. In some embodiments, prior to the step (f), the method may comprise a step of conditioning at least some of interior surfaces of the at least one human-made cavern 14 for receiving the at least some of the waste 17. See e.g., method 800, such as step 809. In some embodiments, after the step (f), the method may comprise a step of sealing off (closing) one or more of: the at least one human-made cavern 14, the launch chamber 7, or the at least one wellbore 5. See e.g., method 800, such as step 813. Some embodiments of the present invention may be characterized as a method for constructing at least one human-made cavern 14 by forming a launch chamber 7 to facilitate reaming tool 12 transitions. In some embodiments, such a method may comprise steps of: the step (a); the step (b); the step (c); the step (d); and the step (e). Systems and methods for human-made cavern construction for use in waste disposal have been described. The foregoing description of the various exemplary embodiments of the invention has been presented for the purposes of illustration and disclosure. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching without departing from the spirit of the invention. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be 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.
	summary
043269176	summary	TECHNICAL FIELD The present invention generally relates to nuclear reactor control methods and particularly to such methods wherein the control is accomplished in response to a variable temperature set point which is a function of load demand. BACKGROUND ART Nuclear control systems for pressurized water reactors are known which are based on average reactor coolant temperature as a set point. These known control systems utilize either a constant average temperature set point or a set point which increases with increasing reactor power. Control of the average temperature to the set point is by reactor control rod movement and/or changes in the boron concentration in the reactor coolant. Rapid power changes have historically depended upon full length control rod motion for reactivity addition and upon partial length control rod motion for power distribution control within the reactor. However, the large changes in linear heat rate experienced by reactor fuel rods in the vicinity of the control rods, particularly those near the partial length control rods, have led to recent concerns about fuel cladding integrity in light of a phenomenon known as pellet-clad interaction. It is well-known that reactor operation with the partial length control rods totally removed from the reactor reduces the risk for pellet-clad interaction but at the same time restricts the maneuvering capability of the reactor based on full length control rods because there is no readily available method of controlling large power imbalances within the core. Rapid power changes utilizing changes in boron concentration, while possible would require very expensive hardware modifications to existing reactor designs and would substantially increase the radioactive waste processing requirements. Because the reactor coolant has an inherent negative moderator coefficient, methods of achieving positive reactivity addition and fast power increases by decreasing the average reactor coolant temperature are known. However, all the known methods employ a temperature drop below a set point which normally increases with power which is the standard control mode for nuclear plants with recirculating steam generators. What was needed was a control system which would allow large power load changes at rates up to five percent full power per minute and which could be implemented at a reasonable cost in conjunction with deletion of the partial length control rods from the existing design of a nuclear reactor system utilizing once-through steam generators. SUMMARY OF THE INVENTION The present invention is a specific method of combining known temperature set point control concepts employing constant average temperature, dropping average temperature, and constant reactor coolant outlet temperature into a single control concept which yields significantly greater benefits on plants employing once-through steam generators than any of the individually known temperature control methods. The invention solves the problems associated with the prior art devices as well as others by providing a method and apparatus for nuclear reactor control which allows reactor power changes at ramp rates up to five percent full power per minute while minimizing waste bleed volumes and pellet-clad interaction concerns for fuel integrity. To accomplish this, a variable average reactor coolant temperature set point is provided which is made a function of the power load demand requirements. This variable set point is made to have a constant temperature set point over the middle portion of the power load range and provides a gradually decreasing temperature set point at the high power end of the power load range. The control of the reactor in response to this variable set point is automatic and done by control rod motion. The programmed average reactor coolant temperature provides moderator temperature reactivity benefits which significantly reduce control rod motion and the need to change boron concentration during maneuvering at high power levels. To meet large power change requirements at rates up to five percent full power per minute, a manual "droop mode" of control is provided wherein the temperature of the reactor coolant is allowed to drop below the forementioned set point within predetermined limits. During this manually-actuated control function, the power requirements are met by varying the feedwater flow to the steam generator to drop the reactor coolant temperature and thereby increase the reactivity of the reactor. Utilizing this mode of control further minimizes control rod motion and boron concentration change requirements while meeting power load demands at rates up to five percent full power per minute. In view of the foregoing, it will be seen that one aspect of the present invention is to provide a method and apparatus for nuclear reactor control utilizing a variable set point which is a function of power load demand and has a constant temperature at the mid range of power load and a decreasing temperature at the high range of power load. Another aspect of the present invention is to provide a manual nuclear reactor control which is based exclusively on feedwater flow and allows high power demand changes with less boron concentration change than would otherwise be required. These and other aspects of the present invention will be more clearly understood upon a review of the foregoing description of the preferred embodiment when considered with the accompanying drawings.
053944496	summary	FIELD OF THE INVENTION The present invention relates to impact limiters for nuclear fuel transportation casks. The impact limiters protect the sealed transportation casks from damage during an impact that may occur during transportation of the cask, for example, from one storage site to another. BACKGROUND OF THE INVENTION One system for on-site storage of spent nuclear fuel utilizes a ventilated concrete horizontal storage module to passively store spent fuel assemblies sealed in a dry shielded canister containment vessel. The dry shielded canister containment vessel has an internal basket assembly with fuel storage locations similar to that of a fuel rack, each of which holds a spent fuel assembly. The loaded dry shielded canister is transferred from the planes spent fuel pool to a horizontal storage module located in an independent spent fuel storage installation using a transfer system that includes a transport trailer. The transfer system also includes an on-site transfer cask for containing the dry shielded canister containment vessel as it is being transferred from the fuel pool to the horizontal storage module. Once transferred to the storage installation, the dry shielded canister containment vessel is removed from the transfer cask and stored in the horizontal storage module until a monitored retrievable storage facility or a permanent storage facility is available. As permanent storage facilities become available, it will be necessary for the dry shielded canister containment vessels to be transported from the on-site temporary storage facility to the off-site storage or disposal facility. Off-site transportation will use a transportation cask to contain the dry shielded canister vessel. Transportation of the spent nuclear fuel to off-site facilities will require that the dry shielded canister containment vessel and transportation cask be transported over public thoroughfares, such has highways, waterways, and railways. During transportation, it is imperative that steps be taken to prevent leakage of radioactive material from the sealed cask and the containment vessel within the cask. Although the containment vessel and cask are shielded and sealed to prevent leakage, there is always a risk of damage to the cask and containment vessel caused by hypothetical accident impacts which might be encountered during transportation. Such impacts may be encountered during a collision involving the vehicle carrying the cask or possibly if the cask were to separate from the transportation vehicle during transportation. One prior design for protecting the transportation cask and containment vessel from damage due to impacts includes "impact limiters" that include round, cylindrical elements carried on each end of the cylindrical transportation cask. Each impact limiter includes an annular region that encases a portion of one end of the cask. Such impact limiters include a foam, wood, or honeycomb material sandwiched between a rigid inner shell and a rigid outer shell. These impact limiters are designed to absorb energy upon impact and protect the transportation cask and containment vessel from damage. Since the impact limiters must accompany the transportation cask over public thoroughfares, the space available for the impact limiters to pass through tunnels, bridges, and other highway, waterway, and railway features limits the overall size of impact limiters. The energy absorbing properties of the impact limiters with round, cylindrical elements often resulted in impact limiters that because of size limitations could not adequately protect a transportation cask that could carry a predefined amount of spent nuclear fuel. Therefore, in order to transport the predefined amount of spent nuclear fuel, additional trips would be necessary which increases the public's exposure to the fuel and the risk of an accidental incident. These previous impact limiters also generally employed one type of material, e.g., foam, wood, or honeycomb with directional crush properties in a given plane between the outer shell and the inner shell. Different densities of foam, wood, or honeycomb were used to soften the impact limiter in certain orientations in order to vary the crush characteristics. In addition, the impact absorbing material used in previous impact limiters was generally oriented radially between the inner and outer shell in order to take advantage of the properties of the material in its strongest direction. Despite the existence of the foregoing impact limiter designs, there continues to be a need for improvements in impact limiters in order to protect the public from the catastrophic effects of an occurrence wherein the transportation casks and containment vessel are breached, and radiation from the spent nuclear fuel escapes. In addition, there continues to be a need for maximizing the amount of fuel that can be transported by a transportation cask and containment vessel so that the number of trips to transport a given amount of fuel can be reduced, thus minimizing the overall risk to the public. SUMMARY OF THE INVENTION In one aspect, the present invention relates to an impact limiter for protecting a nuclear fuel transportation cask and containment vessel, particularly as it is being transported across public thoroughfares. The impact limiter is designed to meet or exceed the regulatory requirements which are in place to protect the public from radiation by minimizing the risk that the integrity of the nuclear fuel transportation cask and containment vessel is breached upon an impact. An impact limiter formed in accordance with this aspect of the present invention includes an annular body having an inner periphery defined by an inner shell that mates with the transportation cask and an outer periphery defined by an outer shell that is noncircular. The annular body includes an impact absorbing material sandwiched between the inner shell and the outer shell. A tapered cap projects from one end of the annular body and includes an outer periphery defined by an outer shell that is noncircular. The tapered cap also includes an impact absorbing material within the outer shell. In a preferred embodiment of this aspect of the present invention, the outer shell of the annular body is multisided, for example, approximating an octagon. Likewise, in a preferred embodiment, the outer shell of the tapered cap in a given cross section is multisided, for example, approximating an octagon. In a specific embodiment of this aspect of the present invention, the impact absorbing material sandwiched between the inner shell and the outer shell of the annular body is different from the impact absorbing material within the outer shell of the tapered cap. The use of two types of impact absorbing material allows for the design of an impact limiter that is capable of effectively protecting the nuclear fuel transportation cask and containment vessel from damage due to impacts in a plurality of orientations. Another embodiment of this aspect of the present invention relates to the use of an aluminum honeycomb with cross laminated corrugations as the impact absorbing material within the annular body, and more particularly, to the axial manner in which bricks of this aluminum honeycomb with cross laminated corrugations are positioned between the inner shell and the outer shell in order to prevent the cask from separating the discreet sections of honeycomb material.
	abstract	The electron beam device includes a source of electrons and an objective deflector. The electron beam device obtains an image on the basis of signals of secondary electrons, etc. which are emitted from a material by an electron beam being projected. The electron beam device further includes a bias chromatic aberration correction element, further including an electromagnetic deflector which is positioned closer to the source of the electrons than the objective deflector, and an electrostatic deflector which has a narrower interior diameter than the electromagnetic deflector, is positioned within the electromagnetic deflector such that the height-wise position from the material overlaps with the electromagnetic deflector, and is capable of applying an offset voltage. It is thus possible to provide an electron beam device with which it is possible to alleviate geometric aberration (parasitic aberration) caused by deflection and implement deflection over a wide field of view with high resolution.
	claims	1. A method for generating an ultrashort charged particle beam, comprising creating a high intensity longitudinal E-field by shaping and tightly focusing in an on-axis geometry a substantially radially polarized laser beam, and using the high intensity longitudinal E-field for interaction with a medium to accelerate charged particles. 2. The method of claim 1, comprising a) converting the polarization of a beam from a high peak power laser to a substantially radial polarization, b) shaping and optimizing the intensity profile and wavefront of the beam; c) tight focusing the radially polarized laser beam in an on-axis geometry with a high numerical aperture optic; and d) accelerating charged particles from the medium by the resulting high intensity longitudinal E-field; in an interaction chamber. 3. The method of claim 1, comprising focusing the radially polarized beam so that radial field projections cancel themselves transversally and align themselves longitudinally, in such a way that a longitudinal to transverse field ratio (LTFR) in the focal plane is maximum for an ultrashort pulse, with the LTFR ratio defined as follows: L ⁢ ⁢ T ⁢ ⁢ F ⁢ ⁢ R = Longitudinal ⁢ ⁢ Field ⁢ ⁢ intensity Transverse ⁢ ⁢ Field ⁢ ⁢ intensity . 4. A system for generating an ultrashort charged particle beam, in an interaction chamber, comprising:a laser system delivering an ultrashort pulse;a polarization converter unit converting a beam from said laser system into a substantially radially polarized laser beam;amplitude beam shaping and transport optics, shaping the substantially radially polarized laser beam;focusing optics tight-focusing the beam received from said transport optics in an on-axis geometry; anda first medium from which charged particles are accelerated by the tight-focused beam. 5. The system of claim 4, wherein said laser system provides ultrashort laser pulses. 6. The system of claim 4, wherein said polarization converter comprises one of: achromatic half wave plates; electro optical modulators, Z-polarization plates, mode polarization combinators and fiber optics. 7. The system of claim 4, wherein said amplitude beam shaping optics comprise at least one of: reflectivity mirrors, hole mirrors, amplitude masks, a diffraction elements, axicons and fiber optics. 8. The system of claim 4, wherein said amplitude beam shaping optics comprise at least one of: reflectivity mirrors, hole mirrors, amplitude masks, a diffraction elements, axicons and fiber optics, in combination with a deformable mirror. 9. The system of claim 4, wherein said focusing optics comprise high numerical aperture optics compatible with ultrashort pulses. 10. The system of claim 4, wherein said focusing optics comprise optics of numerical aperture of at least 0.5, compatible with ultrashort pulses. 11. The system of claim 4, wherein said focusing optics comprise a parabolic mirror in an on axis-geometry, with one of: i) a focal point position near or at the edge of the parabolic mirror; ii) a focal point inside the parabolic mirror and iii) a focal point through a partially cut parabolic mirror. 12. The system of claim 4, wherein said focusing optics comprise a parabolic mirror in an on axis-geometry, with one of: i) a focal point position near or at the edge of the parabolic mirror; ii) a focal point inside the parabolic mirror and iii) a focal point through a partially cut parabolic mirror, in combination with a deformable mirror. 13. The system of claim 4, wherein said focusing optics comprise one of: i) a microscopic objective and ii) a parabola. 14. The system of claim 4, wherein said focusing optics comprise one of: i) a microscopic objective in combination with an ellipsoid and ii) a parabola in combination with an ellipsoid. 15. The system of claim 4, wherein said focusing optics comprise one of: i) a microscopic objective and ii) a parabola, in combination with a deformable mirror. 16. The system of claim 4, wherein said interaction chamber is filled with a low density gas under controlled pressure. 17. The system of claim 4, wherein said interaction chamber is filled with one of helium, oxygen and argon, under controlled pressure. 18. The system of claim 4, wherein said first medium is one of a gas, a liquid, a solid, and a plasma. 19. The system of claim 4, further comprising a second medium located on the propagation axis of the ultrashort charged particle beam, positioned close to the acceleration region, for interaction with the ultrashort charged particle beam. 20. The system of claim 4, further comprising a second medium located on the propagation axis of the ultrashort charged particle beam, positioned close to the acceleration region, for interaction with the ultrashort charged particle beam, said second medium being one of a thin solid target, a thin film, a liquid and a high density gas. 21. A method, comprising:a) radially polarizing, shaping and optimizing a high peak power laser pulse; andb) tight focusing the radially polarized pulse in an on-axis geometry, in a low pressure gas environment, thereby generating a high intensity longitudinal E-field. 22. The method of claim 21, further comprising accelerating charged particles of a first medium with the high intensity longitudinal E-field. 23. The method of claim 21, further comprising accelerating charged particles of a first medium with the high intensity longitudinal E-field into an ultrashort charged particle beam and interacting the ultrashort charged particle beam with a second medium located on the propagation axis of the ultrashort charged particle beam, positioned close to the acceleration region. 24. The method of claim 21, further comprising using the high intensity longitudinal E-field for interaction with a medium composed of electrons, protons and ions to accelerate electrons in the propagation axis, thereby creating a space charge field that accelerates protons and ions from the medium. 25. The method of claim 21, further comprising accelerating charged particles of a first medium with the high intensity longitudinal E-field into an ultrashort charged particle beam and interacting the ultrashort charged particle beam with a second medium composed of electrons, protons and ions, located on the propagation axis of the ultrashort charged particle beam, positioned close to the acceleration region, thereby accelerating protons and ions from the second medium. 26. A method for generating X ray or particles sources, comprising creating a high intensity longitudinal E-field by tightly focusing a radially polarized laser beam in an on-axis geometry, using the high intensity longitudinal E-field for interaction with a first medium to accelerate charged particles and generate an ultrashort charged particle beam, and interacting the ultrashort charged particle beam with a second medium located close to the acceleration region.
042784980	abstract	Earthquake-proof mounting support for control rod drives of nuclear reactors having a generally cylindrical reactor pressure vessel formed with a convex wall at least at one end thereof and including control rods with control rod drive shafts coupled thereto and mounted so as to be movable in axial direction thereof within tubular drive housings extending pressure-tightly through the end convex wall and sealed against the outside, the tubular drive housings comprising tube member forming respective feed-through passageways for the control rod drive shafts, the tube members having respective portions thereof extending with respectively varying lengths outside and beyond the convex wall to a given horizontal plane, and a support grid formed of a plurality of grid bars articulatingly connecting the tube members at respective free ends thereof outside the convex wall, respectively, to one another.
	claims	1. A storage container system, the system comprising:a plurality of storage containers each including a plurality of side walls, each of the side walls having a shield mounting point, wherein the plurality of storage containers are arrangeable in a plurality of storage configurations, each storage configuration including a plurality of exposed side walls along an outermost portion of the storage configuration, the exposed side walls each formed by a side wall of storage container that is not mated with a side wall of an adjacent storage container;a plurality of shield panels each having a shield mounting point, each of the plurality of shield panels having a different shielding material property from the plurality of storage containers and configured to be removably coupled to one of the plurality of exposed side walls; anda plurality of shield mounts configured to removably couple the plurality of shield panels to the plurality of exposed side walls, wherein each of the plurality of shield mounts includes a first slot and a second slot, the first slot configured to engage with the mounting point on one of the plurality of storage containers, the second slot engaging the mounting point on one of the plurality of shield panels. 2. The storage container system of claim 1, wherein, when one of the plurality of shield mounts is engaged with the one of the plurality of storage containers, and wherein a top surface of the shield mount is flush with a top surface of the storage container. 3. The storage container system of claim 2, wherein, when one of the plurality of shield mounts is engaged with the one of the plurality of storage containers, and wherein an outer surface of the shield mount is flush with one of the plurality of side walls of the storage container. 4. The storage container system of claim 1, wherein one of the first slot and the second slot is a closed slot that is sized and shaped to fit over a guide on one of the plurality of shield panels. 5. The storage container system of claim 1, wherein the plurality of shield mounts are slidably engageable with the plurality of storage containers and are slidably engageable with the plurality of shield panels. 6. The storage container system of claim 1, wherein the shield mount is adjustable to accommodate shield panels of different thicknesses. 7. The storage container system of claim 6, wherein the shield mount includes a channel, a mounting peg, and a container peg, and wherein at least one of the mounting peg and the container peg is slidable along the channel. 8. The storage container of claim 1, wherein at least one of the plurality of the shield mount includes a toggle clamp. 9. A storage container system, the system comprising:a plurality of storage containers each including four side walls, each of the side walls having a shield mounting point, wherein the plurality of storage containers are arrangeable in a plurality of storage configurations, each storage configuration having a plurality of internal side walls and a plurality of exposed side walls, the internal side walls formed by side walls of adjacent storage containers that are mated together, the exposed side walls formed by a side wall of one of the plurality of storage containers that is not mated with a side wall of an adjacent one of the plurality of storage containers;a plurality of shield panels each having a shield mounting point, each of the plurality of shield panels having a different shielding material property from the plurality of storage containers and configured to be removably coupled to one of the plurality of exposed side walls; anda plurality of shield mounts configured to removably couple the plurality of shield panels to the plurality of exposed side walls. 10. The storage container system of claim 9, wherein the at least one of the plurality of shield panels includes a tabbed edge configured to overlap with another one of the plurality of shield panels. 11. The storage container system of claim 9, wherein the plurality of shield mounts each includes a first slot and a second slot, the first slot configured to engage with the mounting point on one of the plurality of storage containers, the second slot engages the mounting point on one of the plurality of shield panels. 12. The storage container system of claim 11, wherein the plurality of shield mounts each includes a top surface configured to be flush with a top surface of one of the plurality of storage containers. 13. A system of storage containers arranged in a storage configuration, the system comprising:a plurality of storage containers selectively arrangeable in a storage configuration, wherein when arranged in a storage configuration each of the plurality of storage containers has at least one internal surface adjacent an internal face of another of the plurality of storage containers, and at least some of the plurality of storage containers have at least one external surface along an outermost surface of the storage configuration;a plurality of shield panels having a different shielding material property from the plurality of storage containers and configured to be removably coupled to the storage containers such that the plurality of shield panels each lie adjacent to the at least one external surface of the plurality of storage containers; anda plurality of shield mounts configured to removably couple the plurality of shield panels to the plurality of storage containers having external surfaces. 14. The system of claim 13, wherein each of the plurality panels has a different material composition from the plurality of storage containers to provide the different shielding material property. 15. The system of claim 13, wherein the plurality of shield panels are each formed from a material composition configured to provide more radiation shielding than the plurality of storage containers. 16. The system of claim 13, wherein each of the plurality of shield panels is configured to provide at least one of nuclear radiation, thermal, magnetic flux, electromagnetic flux, radio, and impact shielding properties. 17. The system of claim 13, wherein the different shielding material property includes an increased shielding ability relative to the plurality of storage containers. 18. The system of claim 1, wherein each of the plurality of storage containers defines a complete enclosure. 19. The system of claim 1, wherein the plurality of shield panels are each substantially planar and configured to completely cover the one of the exposed side walls directly face-to-face therewith. 20. The system of claim 1, wherein the plurality of shield panels are each configured to at least partially cover the outermost portion of the one of the exposed side walls, directly face-to-face therewith.
	abstract	An imaging method and apparatus for forming images of substantially the same area on a sample for defect inspection within the area are disclosed. The disclosed method includes line-scanning the charged particle beam over the area to form a plurality of n*Y scan lines by repeatedly forming a group of n scan lines for Y times. During the formation of each group of n scan lines, an optical beam is, from one line scan to another, selectively illuminated on the area prior to or simultaneously with scanning of the charged particle beam. In addition, during the formation of each group of n scan lines, a condition of illumination of the optical beam selectively changes from one line scan to another. The conditions at which individual n scan lines are formed are repeated for the formation of all Y groups of scan lines.
	abstract	A method for removing radioactive cesium and/or iodine from a radioactive substance in liquid and/or a solid matter using a hydrophilic resin composition comprising a hydrophilic resin and a metal ferrocyanide compound, wherein the hydrophilic resin includes at least one hydrophilic resin selected from the group consisting of a hydrophilic polyurethane resin, a hydrophilic polyurea resin, and a hydrophilic polyurethane-polyurea resin each having at least a hydrophilic segment, and a metal ferrocyanide compound is dispersed in the hydrophilic resin composition in a ratio of at least 1 to 200 mass parts relative to 100 mass parts of the hydrophilic resin.
	summary
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	abstract	According to an embodiment, a pressurized water reactor plant has a primary system which includes: a reactor vessel for housing a reactor core which is cooled by a primary coolant, a single steam generator, a hot leg pipe for connecting the reactor vessel and the steam generator, cold leg pipes, at least two primary coolant pumps, and a pressurizer for pressurizing the primary coolant pressure boundary in which the primary coolant flows. The plant also has: a passive cooling and depressurization system which is a primary depressurization means for equalizing the primary system pressure to the secondary system pressure at the time of a tube rupture accident of the steam generator, and a reactor containment vessel containing the primary system and cooling the primary system by air cooling. Thus, a compact pressurized water rector with high economic efficiency, safety, and reliability can be provided.
	description	FIG. 1 is a front sectional view, with parts cut away, of a boiling water nuclear reactor 10. However, the present invention is equally applicable to other types of nuclear reactors, and the description of reactor 10 is therefore provided for illustrative purposes only rather than by way of limitation. Reactor 10 includes a reactor pressure vessel (RPV) 12 that is generally cylindrical in shape and is closed at one end by a bottom head 14 and at its other end by a removable top head 16. Reactor 10 is located within a reinforced concrete containment vessel (RCCV) 18 that includes a side wall 20. RCCV side wall 20 includes openings (not shown in FIG. 1) located to receive steam lines, feedwater lines, emergency cooling lines, instrumentation and control lines, electrical power lines, equipment hatches, and/or personnel access hatches (not shown). RPV 12 includes a cylindrically shaped core shroud 22 that surrounds a reactor core 24. Shroud 22 is supported at one end by a shroud support 26 and includes a removable shroud head 28 at the other end. An annulus 30 is formed between shroud 22 and an RPV side wall 32. A pump deck 34, which has a ring shape, extends between shroud support 26 and RPV side wall 32. Pump deck 34 includes a plurality of circular openings 36, with each opening housing a jet pump assembly 38. Jet pump assemblies 38 are circumferentially distributed around core shroud 22. Heat is generated within core 24, which includes fuel bundles 40 of fissionable material. Water circulated up through core 24 is at least partially converted to steam. Steam separators 42 separates steam from water, which is recirculated. Residual water is removed from the steam by steam dryers 44. The steam exits RPV 10 through a steam outlet 46 near vessel top head 16. The amount of heat generated in core 24 is regulated by inserting and withdrawing control rods 48 of neutron absorbing material. To the extent that control rods 48 are inserted into fuel bundles 40, they absorb neutrons that would otherwise be available to promote the chain reaction which generates heat in core 24. Control rod guide tubes 50 maintain the vertical motion of control rods 48 during insertion and withdrawal. Control rod drives 52 effect the insertion and withdrawal of control rods 48. Control rod drives 52 extend through bottom head 14. Fuel bundles 40 are aligned by a core plate 54 located at the base of core 24. A top guide 56 aligns fuel bundles 40 as they are lowered into core 24. Core plate 54 and top guide 56 are supported by core shroud 22. FIG. 2 is a top sectional view of RCCV side wall 20 having openings 58 that extend from an outer surface 60 to an inner surface 62 of wall 20. Openings 58 are located to receive steam lines, feedwater lines, emergency cooling lines, instrumentation and control lines, electrical power lines, equipment hatches, and/or personnel access hatches (not shown). Terminated at side wall openings 58 are reinforcing bars 64. Reinforcing bars 64 include vertical reinforcing bars 66 and horizontal hoop reinforcing bars 68. Reinforcing bars 66 are connected to reinforcing plates 70. Reinforcing bars 66 and reinforcing plates 70 can be fabricated from any suitable material, for example, structural steel. FIG. 3 is a front view of reinforcing plate 70. Reinforcing plate 70 has a substantially square shape and includes an opening 72 that is substantially aligned with a side wall opening 58 (shown in FIG. 2). Reinforcing plate opening 72 is substantially circular. In alternate embodiments, reinforcing plate 70 and/or opening 72 can have different shapes such as a polygonal shape or an elliptical shape. A plurality of layers of reinforcing bars 64 connect to reinforcing plate 70 with reinforcing bar terminators 76. Reinforcing plate 70 includes an outer flange 78 at a peripheral edge 80 that surrounds a reinforcing plate intermediate portion 82. Reinforcing bar terminators are attached to outer flange 78. A reinforcing plate inner flange 84 is adjacent reinforcing plate opening 72 and is sized to receive a penetration sleeve 86 that is secured to reinforcing plate inner flange 84. Penetration sleeve 86 includes a bore 88 to accommodate steam lines, feedwater lines, instrumentation and control lines, or electrical power lines (not shown). In one embodiment, outer flange 78 has a thickness greater than a thickness of inner flange 84 which has a thickness greater than a thickness of intermediate portion 82. In an another embodiment, reinforcing plate opening 72 includes a diameter larger than an outer diameter of a corresponding penetration sleeve 86. In other words, reinforcing plate opening 72 has a diameter larger than an inner diameter of penetration sleeve 86 plus twice the thickness of a penetration sleeve wall 90. Reinforcing plate 70 is installed into RCCV shell side wall 20 (shown in FIG. 1) by positioning reinforcing plate 70 in side wall 20 at a location corresponding opening 58. Vertical and horizontal hoop reinforcing bars 66 and 68 are coupled to reinforcing bar terminators 76 which are attached to reinforcing plate 70. A penetration sleeve 86 is positioned in reinforcing plate opening 72 and secured to reinforcing plate inner flange 84, for example, by welding. Concrete is subsequently used to form RCCV shell side wall 20. FIG. 4 is a front view of two reinforcing plates 70 connected together at an outer edge contact region 92 to form a double reinforcing plate 94. Reinforcing plates 70 are welded together at contact region 92, and reinforcing plates 70 do not include a flange 74 at contact region 92. In this embodiment, RCCV shell side wall 20 has two adjacent openings (not shown) located to accommodate two penetrations (not shown). Vertical reinforcing bars 66 and horizontal hoop reinforcing bars 68 are terminated around the respective openings. Accordingly, vertical reinforcing bars 66 and horizontal hoop reinforcing bars 68 are attached to outer flanges 74 of reinforcing plates 70 with reinforcing bar terminators 76. This particular configuration is provided in order to illustrate the combination of reinforcing plates in order to accommodate a plurality of adjacent RCCV shell side wall openings. The present invention may be practiced with a variety of configurations of adjacent side wall openings, with regard to number and relative location, similar or dissimilar to the particular configuration presented in FIG. 4. Therefore, the configuration of reinforcing plates 70 in FIG. 4 is provided for illustrative purposes only and is not intended to limit the invention to any particular configuration. In addition, multiple reinforcing plates may be positioned adjacent one another, in order to accommodate situations wherein one side wall opening is configured to include a plurality of penetration sleeves 86. FIG. 5 is a front view of a reinforcing plate 96 that includes a discontinuous reinforcing plate outer flange 98 in accordance with another embodiment of the present invention. Flange 98 partially surrounds a reinforcing plate intermediate portion 100. Particularly, outer flange 98 surrounds reinforcing plate 96 along a first side 102 and an opposing second side 104. Reinforcing plate 96 includes reinforcing bar extensions 106. Vertical reinforcing bars 66 are connected to reinforcing bar terminators 76 which are attached to extensions 106. Extensions 106 are welded to reinforcing plate intermediate portion 100. FIG. 6 is a top view of reinforcing plate 96, at first side 102. Reinforcing bar extensions 106 are attached to reinforcing plate intermediate portion 100. Specifically, vertical reinforcing bar 66 is connected to terminator 76 which is attached to an extension plate 108. Extension plate 108 is connected to extension flanges 110 which are attached to plate intermediate portion 100. Extensions 106 minimize eccentricity in the connections between horizontal hoop reinforcing bars 68, vertical reinforcing bars 66, and reinforcing plate 96. FIG. 7 is a top view of reinforcing plate 112 in accordance with another embodiment of the present invention. A plurality of reinforcing bar extensions 114 (one shown) are coupled to reinforcing plate 112. Reinforcing bar extensions 114 include brackets 116 which receive terminators 76. Brackets 116 are connected to an reinforcing plate intermediate portion 118. Reinforcing bar extensions 114 are provided to accommodate a reinforcing plate 112 that does not align with vertical reinforcing bars 66 while aligning with horizontal reinforcing bars 68. Reinforcing plates 96 and 112 can include a variety of reinforcing bar extensions similar or dissimilar to reinforcing bar extensions 106 and 114. Therefore, while specific configurations of reinforcing bar extensions have been discussed, reinforcing bar extensions 106 and 114 are provided for illustrative purposes only and are not intended to limit the invention to any particular type of reinforcing bar extension. In addition, a variety of reinforcing bar extension configurations may be used in combination with a variety of reinforcing bar terminator configurations within the scope of the present invention. FIG. 8 shows a front view of reinforcing plate 70 formed from several reinforcing plate sections 120 and 122. The reinforcing plate sections 120 and 122 are welded together on site to facilitate a timely installation. Particularly, reinforcing plate 70 is formed from two half-plate sections 120 and 122 with seams 124 located along a horizontal centerline. Reinforcing plates 70, 96, and 112 described above provide a positive means for load transfer across an opening 58 in an RCCV side wall 20 where reinforcing bars 64 are terminated. Reinforcing plates 70, 96, and 112 eliminate congestion problems due to excessive usage of reinforcing bars 64 adjacent to an opening 58, as well as the need to locally increase the thickness of RCCV side wall 20 adjacent to opening 58. Additionally, fabricating RCCV 18 using reinforcing plates 70, 96, and 112 shortens and improves construction schedules. Further, reinforcing plates 70, 96, and 112 are particularly useful when the diameter of an opening 58 is larger than the thickness of RCCV side wall 20. 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.
	claims	1. A robotic apparatus for remotely inspecting at least one component in an annulus region of a reactor pressure vessel of a nuclear power plant, comprising:a partial track positioned on an annular rim of a core shroud in the reactor pressure vessel and horizontally movable along the rim;a frame assembly, comprising:a frame movably connected to the partial track such that the frame is horizontally movable along the partial track;at least one mast assembly;at least one mast positioning assembly; andat least one inspection device attached to the at least one mast assembly; anda braking system connected to the partial track and the frame assembly, structured such that when activated, the partial track is stationary and the frame assembly is horizontally movable along the partial track and when deactivated, the partial track is horizontally movable along the annular rim of the core shroud and the frame assembly is stationary. 2. The apparatus of claim 1, wherein a first mast assembly is positioned on one side of the frame and a second mast assembly is positioned on an opposite side of the frame. 3. The apparatus of claim 1, wherein a first mast positioning device is positioned on one side of the frame and a second mast positioning assembly is positioned on an opposite side of the frame. 4. The apparatus of claim 1, wherein a first pan and tilt assembly is positioned on one side of the frame and a second pan and tilt assembly is positioned on an opposite side of the frame. 5. The apparatus of claim 1, wherein the frame assembly includes a positioning motor and gear combination to move the frame assembly along the track. 6. The apparatus of claim 1, wherein the inspection device is a camera. 7. The apparatus of claim 1, wherein the at least one mast assembly comprises a mast that is capable of becoming rigidly stable in an extended tube form and a retracted rolled form.
050874098	claims	1. A multiple shell pressure vessel comprising a top head section comprising a top head flange having a lower bearing surface, a shell course section comprising a first inner shell having a top rim, a first inner shell flange attached to said top rim of said first inner shell and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said first inner flange to said lower bearing surface of said top head flange, a second outer shell adapted to telescopically enclose said first inner shell and having a top rim, a second outer shell flange attached to said top rim of said second outer shell and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said second outer shell flange to said lower bearing surface of said first flange, a top tendon skirt having a bottom flange, means for connecting said bottom flange to said top head section proximate said top head flange, a bottom tendon skirt having a top flange, means for connecting said top flange to said second outer shell proximate said lower bearing surface of said second flange, means connected to said top and bottom tendon skirts for compressing said flanges between said top and bottom tendon skirts, and a radial spacer bearing ring disposed about the outer surface of said shell module first inner shell and adapted to engage the inner surface of said shell module second outer shell, said radial spacer bearing ring located a predetermined distance from said first inner shell flange to equalize torsional forces on said first inner shell flange. a top head module comprising a top head flange having a lower bearing surface, a shell course module comprising a first inner shell having a top rim, a first inner shell flange attached to said top rim of said first inner shell and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said first inner flange to said lower bearing surface of said top head flange, an intermediate shell adapted to telescopically enclose said first inner shell and be spaced apart therefrom comprising a top rim, an intermediate shell flange attached to said top rim and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said intermediate flange to said lower bearing surface of said first inner shell flange, an outer shell adapted to telescopically enclose said intermediate shell and be spaced apart therefrom comprising a top rim, an outer shell flange attached to said outer shell top rim and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said outer shell flange to said lower bearing surface of said intermediate shell flange, a top tendon skirt having a bottom flange, means for connecting said bottom flange to said top head module proximate said upper bearing surface of said top head flange, a bottom tendon skirt having a top flange, means for connecting said top flange to said outer shell proximate said lower bearing surface of said outer shell flange, and means connected to said top and bottom tendon skirts for compressing said flanges between said top and bottom tendon skirts. an insulating material disposed in the space between said first inner shell and said intermediate shell, and a low melting point thermal conducting material disposed in the space between said outer shell and said intermediate shell. a first radial spacer bearing ring disposed about the outer surface of said shell module first inner shell and adapted to engage the inner surface of said shell module intermediate shell, said first radial spacer bearing ring located a predetermined distance from said first inner shell flange to equalize torsional forces on said first inner flange, and a second radial spacer bearing ring disposed about the outer surface of said shell module intermediate shell and adapted to engage the inner surface of said shell module outer shell, said radial spacer bearing ring located a predetermined distance from said intermediate shell flange to equalize torsional forces on said intermediate flange. means for cooling the outer shell of said pressure vessel. means for controlling the pressure of said low melting point thermal conducting material disposed in the space between said outer shell and said intermediate shell. a top head section comprising a top head bottom rim, a top head flange attached to said bottom rim of said top head section, said top head flange having an upper bearing surface and a lower bearing surface, a nozzle course section comprising a nozzle course top rim, a nozzle course top flange attached to said nozzle course top rim and having a top bearing surface and a lower bearing surface, means for sealably connecting said upper bearing surface of said nozzle course top flange to said lower bearing surface of said top head flange, a nozzle course bottom rim, a nozzle course bottom flange attached to said nozzle course bottom rim and having an upper bearing surface and a lower bearing surface, a shell course section comprising a first inner shell having a top rim, a first flange attached to said top rim of said first inner shell and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said first flange to said lower bearing surface of said nozzle course bottom flange, a second outer shell adapted to telescopically enclose said first inner shell and having a top rim, a second flange attached to said top rim of said second outer shell and having a lower bearing surface and an upper bearing surface, means for sealably connecting said upper bearing surface of said second flange to said lower bearing surface of said first flange, a top tendon skirt having a bottom flange, means for connecting said bottom flange to said top head section proximate said upper bearing surface of said top head flange, a bottom tendon skirt having a top flange, means for connecting said top flange to said second outer shell proximate said lower bearing surface of said second flange, and means connected to said top and bottom tendon skirts for compressing said flanges between said top and bottom tendon skirts. a first shell course bearing plate disposed between the lower bearing surface of said first inner shell flange and the upper bearing surface of said second outer shell flange. a top tendon skirt top flange a top tendon skirt frusto-conical section disposed between said top tendon skirt bottom flange and said top tendon skirt top flange, and said bottom tendon skirt comprises a bottom tendon skirt bottom flange, a bottom tendon skirt frusto-conical section disposed between said bottom tendon skirt top flange and said bottom tendon skirt bottom flange. at least three tension members connected between said top tendon skirt top flange and said bottom tendon skirt bottom flange and equiangularly spaced around said flanges outside said pressure vessel, said first and second shell course flanges stepped relative to each other, and a radial spacer bearing ring disposed between said first inner and said second outer shells of said shell course and located proximate a force line which produces zero flange torsion. the point of connection of said tension members to said top tendon skirt top flange and said bottom tendon skirt bottom flange are approximately coincident with the frusto-conical surface defined by said top tendon skirt frusto-conical section and said bottom tendon skirt frusto-conical section. 2. A multiple shell pressure vessel comprising 3. A multiple shell pressure vessel as claimed in claim 2 further comprising 4. The multiple shell pressure vessel as claimed in claim 2 further comprising 5. The multiple shell pressure vessel as claimed in claim 2 further comprising 6. The multiple shell pressure vessel as claimed on claim 2 further comprising 7. A multiple shell pressure vessel comprising 8. The multiple shell pressure vessel as claimed in claim 7 further comprising 9. The multiple shell pressure vessel as claimed in claim 7 wherein said top tendon skirt comprises 10. The multiple shell pressure vessel as claimed in claim 9 comprising 11. The multiple shell pressure vessel as claimed in claim 10 wherein
	summary
	description	The strontium-89 production method is based upon a unique ability to effect not only the final radioisotopes, but also its precursors produced as a result of the nuclear transformation of products in the decay chain of elements with mass 89 occurring in a nuclear solution reactor. The decay chain is Se89xe2x86x92Br89xe2x86x92Kr89xe2x86x92Rb89xe2x86x92Sr89. A liquid fuel nuclear reactor having a uranyl sulfate water solution (UO2SO4) core is used in the present invention. Uranium-235 and/or uranium-233 can be used as fissionable material in the fuel solution of uranyl sulfate. The Russian Argus reactor was the particular reactor used. It used 90% enriched U235 in a concentration of 73.2 g/l in the water solution. The uranyl sulfate water solution volume (pH=1) was 22 liters. It can be brought up to its rated power of 20 kW in 20 minutes. The thermal neutron flux density in the central channel is 5xc3x971011 neutrons/cm2s. Homogenous solution fuel reactors have a number of advantages over hard fuel reactors. They have large negative temperature and power reactivity effects, which provides for their high nuclear safety. The core design is much simpler. There are no fuel element cladding spacers and other parts reducing the neutron characteristics. Solution preparation is much cheaper than fuel element production. Solution fuel loading (pouring) is much easier too, and makes it possible to change the fissionable material concentration in fuel or solution volume if necessary. There can be no local over-heating provoked by power density field deformations in the core of the solution reactor, thanks to good conditions for heat transfer. These reactors are simple and reliable in operation and do not require a large staff for their operation. A number of radioactive inert gases are produced in uranyl sulfate solution reactor during its operation, including the desired krypton-89. The majority of these gases leave the solution in the gas phase, accumulating above the liquid surface. The process by which this takes place is based on xe2x80x9cradiolytic boiling.xe2x80x9d Gas bubbles containing water vapor and hydrogen form in the tracks of fission fragments. The vapor is condensed within about 10xe2x88x928 seconds and a gas bubble forms having a radius of about 10xe2x88x925 cm. Fission fragments either get into the gaseous bubble during its generation or afterwards by diffusing from the solution. They then migrate to the surface of the fuel solution. The radiolytic gas bubbles rise to the surface in only a couple of seconds, making it possible to remove relatively short-life radioisotopes, such as krypton-89. Bubbling the fuel with an inert gas can speed up this process of removal of fragment gases. Krypton-89, along with small quantities of other fission fragment elements are produced at the same time. The main chains of fission products"" decay resulting in strontium radionuclides whose gaseous precursors have a half-life of more than one second are shown in FIGS. 1A to 1C. One of the fission products is krypton-89 (Kr89), a radioactive isotope of the inert gas, krypton, preceding strontium-89 in the decay chain of fission products with an atomic mass of 89. It has a half-life of 3.2 minutes, decaying to rubidium-89. Rubidium-89 decays with a half-life of 15.4 minutes to the desired strontium-89. Other isotopes of krypton, however, also bubble to the surface, including the highly undesirable precursor to strontium-90, krypton-90. Krypton-90 decays in 33 seconds to rubidium-90 and in 2.91 minutes to strontium-90. Because krypton-89 and krypton-90 are gases and because of the differential in half-life of the two isotopes, it is relatively easy to separate the two. There is no such possibility in the core of a typical nuclear reactor in which the fissionable material, e.g., U235, is a hard oxide or metal enclosed in the cladding of fuel elements. Other radioactive components with half-lives short compared to krypton-89 can also be readily separated. The high productivity of this method is primarily the result of: (1) the large cross-section of the decay reaction (n,f) of up to 600-800xc3x9710xe2x88x9224 for thermal neutrons for such nuclei as U235, U233, or Pu239; and (2) the ability to remove the krypton-89 from other gaseous end products of the reaction due to differential decay. For a unit target, this method is about 1000 times more efficient than the prior art. Because the half-life of krypton-89 (190.7 seconds) is significantly longer than that of krypton-90 (32.2 seconds), it is possible to decrease the content of strontium-90 in the mixture to about 10xe2x88x924 atomic percent, providing for high radioisotope purity in the strontium-89. The method of strontium extraction via a continuous gas loop is illustrated in FIG. 2. The process is begun after the transitional processes bound up with the reactor start-up are finished (about 20 minutes). Referring to FIG. 2, valves 3 and 9 are opened and a gas pump 5 is turned on. Gas from above the fuel solution is moved to a delaying line 4. The delaying line is designed to keep the gas from arriving at the precipitation device 7 for the time necessary for krypton-90 to decay to strontium-90, thereby removing it from the gas mixture. Rubidium and strontium isotopes that have not precipitated in the delaying line settle in the filter 6. The diameter of the delaying line pipe is determined by the condition of laminar gas flow in the pipe. The pipe""s length is determined by the delay time for a preset gas flow rate. (If the gas flow rate is about 2 l/min, a delay time of ten minutes is achieved when the pipe inner diameter is 10 mm and the pipe length is 255 meters. If the diameter were 20 mm, a delay line length of 64 meter would give a 10-minute delay.) A ten minute delay yields a radionuclide purity (Sr90/Sr89) of about 3xc3x9710xe2x88x928. After going through the delaying line, the gas arrives at the strontium-89 precipitation device 7. The precipitation device is another pipe whose diameter and length are designed for a delay period sufficient for the remaining krypton-89 to decay to strontium-89. This would be about 30 minutes at a gas flow rate of 2 l/minute. Those isotopes of rubidium and strontium, which have not precipitated in the precipitation device, pass through it and settle in the filter 8. The gas, less those fission fragments that have precipitated out or otherwise been removed, is returned to the reactor. After the cycle of strontium-89 production is completed, the valves 3, 9 are closed. Strontium-89 deposited in the precipitation device and in the filter 8 are subsequently extracted. The circulating gas flow removes water vapor from the fuel solution. The initial part of the gas pipe 10 shown in FIG. 2 is inclined so that water vapor is condensed on the pipe wall and the water runs back into the reactor vessel by gravity preventing fuel solution water loss. A trap 11 is indicated in FIG. 2 at the entrance to the gas loop to hinder non-gaseous fission fragments moved by the gas flow over the fuel solution from getting into the gas loop. If the precipitation rate of strontium-89 is high, most of it will accumulate in the precipitation device 7. An acid solution can then be used to wash out strontium-89 from which it is subsequently extracted and subjected to radiochemical purification. If the precipitation rate is low, most of the strontium-89 will accumulate in the filter 8. This filter can consist of thin, fine nets of stainless steel. The strontium-89 can then be extracted by pumping an acid solution through the filter. Alternatively, a removable filter could be used with extraction of the strontium-89 being done at a later time.
	summary
	summary
	abstract	A method is presented for collecting and removing radon from a confined area, a storage box or articles of clothing. The method includes collecting radon from the confined area or around a storage box via at least one collector, connecting each of a plurality of radon adsorbers to a corresponding power supply or power source such as a battery, capacitor, fuel cell, etc. diverting, via a plurality of valves, the collected radon or radon daughters through one or more of the plurality of radon adsorbers, and receiving, via a plurality of radon storage units, radon or radon daughters held by the plurality of radon adsorbers for a predetermined period of time.
	claims	1. A fuel element, comprising: a fuel element body having a fuel element axis, a polygonal internal cross section perpendicular to said fuel-element axis, a first region, and a second region; and fuel rods having outer surfaces disposed substantially parallel to said fuel-element axis and substantially perpendicular to said polygonal internal cross section in said fuel element body, in said first region a ratio of a free area of said polygonal internal cross section to an area through which said fuel rods pass in said first region is smaller than in said second region, said first region forming a first corner of said polygonal internal cross section and said second region forming second corners of said polygonal internal cross section, and a distance between said outer surfaces of each two adjacent fuel rods increasing monotonically in any one direction along said polygonal internal cross section starting from said first corner of said fuel element body. 2. The fuel element according to claim 1 , wherein said distance between said outer surfaces is on average smaller in said first region than in said second region. claim 1 3. The fuel element according to claim 1 , wherein said fuel rods have identical diameters. claim 1 4. The fuel element according to claim 1 , wherein said distance between said outer surfaces starting from said first corner increases in said one direction in accordance with a linear, convex or concave function. claim 1 5. The fuel element according to claim 1 , wherein said fuel rods form a configuration over said polygonal internal cross section that is substantially in mirror symmetry relative to a diagonal of said polygonal internal cross section starting from said first corner of said polygonal cross section. claim 1 6. The fuel element according to claim 1 , wherein said polygonal internal cross section is square shaped. claim 1 7. The fuel element according to claim 1 , wherein said fuel element body has a first side and a second side, said fuel rods include a first fuel rod adjacent said first side and a second fuel rod adjacent said second side, said first fuel rod starting from said first corner is at a first distance from said first side which is smaller than a second distance of said second fuel rod from said second side. claim 1 8. The fuel element according to claim 1 , including a water-tube configuration disposed in said fuel element body and disposed substantially parallel to said fuel rods. claim 1 9. The fuel element according to claim 8 , wherein said first region is square shaped and borders said water-tube configuration, said water-tube configuration having a corner lying opposite said first corner. claim 8 10. The fuel element according to claim 1 , wherein said second region is polygonal, and has a section forming a corner of said second region, said corner of said second region being opposite said first corner, a ratio of a free area of said polygonal internal cross section in said section to an area through which said fuel rods pass through said section is greatest. claim 1 11. The fuel element according to claim 1 , wherein: claim 1 said fuel element body is a grid divided up by spacer grids forming a plurality of rectangular meshes, each of said rectangular meshes having a mesh opening formed therein; said fuel rods are disposed in lines substantially parallel to one another and in columns substantially perpendicular to said lines; and at least one of said fuel rods being disposed in one of said rectangular meshes. 12. The fuel element according to claim 11 , wherein an area of said mesh opening of said rectangular meshes in said first region is on average smaller than in said second region. claim 11 13. The fuel element according claim 8 , wherein said water-tube configuration is laterally offset from said fuel-element axis. claim 8 14. The fuel element according to claim 1 , wherein said fuel rods have outer surfaces disposed parallel to said fuel-element axis and perpendicular to said polygonal internal cross section in said fuel element body. claim 1 15. A fuel element, comprising: a fuel element body having a fuel element axis and an internal cross section perpendicular to said fuel-element axis, a first corner and second corners; and fuel rods having outer surfaces disposed substantially parallel to said fuel-element axis and substantially perpendicular to said internal cross section of said fuel element body, said first corner having a ratio of a free area of said internal cross section to an area through which said fuel rods pass being smaller than said second corners and a distance between said outer surfaces of said fuel rods increasing monotonically in any one direction perpendicular to said fuel element axis starting from said first corner of said fuel element body. 16. The fuel element according to claim 15 , wherein said distance between said outer surfaces of said fuel rods is on average smaller for fuel rods in said first corner than for fuel rods in said second corner. claim 15 17. The fuel element according to claim 15 , wherein said fuel rods-have identical diameters. claim 15 18. The fuel element according to claim 15 wherein said distance between said outer surfaces starting from said first corner increases in said one direction in accordance with a linear, convex or concave function. claim 15
	claims	1. A method for manufacturing a core barrel which is to be disposed in a reactor pressure vessel of a pressurized water reactor and includes a main body barrel including a flange configured to be attached to the reactor pressure vessel, an upper barrel extending downward from the flange, and a lower barrel extending downward from the upper barrel, the core barrel to couple with the lower core support plate thorough a short ring and to hold a reactor core including a plurality of fuel assemblies, the method comprising:welding a first end part of a short ring in an axial direction of the core barrel, which has an axial direction length shorter than the lower barrel, to an upper portion of a lower core support plate;machining the lower core support plate through an upper end portion of the short ring that has been welded to the lower core support plate, the machining of the lower core support plate including forming:a placement surface on which the plurality of fuel assemblies is to be placed; anda fuel alignment pin hole, in which a fuel alignment pin for positioning the plurality of fuel assemblies is to be inserted; andwelding, after the machining of the lower core support plate, a lower end of the lower barrel of the main body barrel which covers the reactor core including the plurality of fuel assemblies to be placed on the placement surface to a second opposite end part of the short ring in the axial direction. 2. The method for manufacturing a core barrel according to claim 1, wherein before the machining of the lower core support plate, a heat treatment is performed on a weld line formed between the short ring and the lower core support plate. 3. The method for manufacturing a core barrel according to claim 1, wherein the short ring has an axial direction length that the lower core support plate can be machined after welding the short ring to the lower core support plate. 4. The method for manufacturing a core barrel according to claim 1, wherein the core support plate includes a junction part is provided on an outer side, in the radial direction, of the placement surface, and the lower end of the short ring is welded to the junction part. 5. The method for manufacturing core barrel according to claim 1, wherein when of the lower core support plate is machined, the lower core support plate and the short ring are machined to final forms which are same shapes as when the core barrel is completed.
	summary
	claims	1. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation; andfirst and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element,wherein this sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation. 2. Sensor according to claim 1, in which the material has an effective atomic number close to 10. 3. Sensor according to claim 1, in which the axis of the element is an axis of symmetry of revolution for this element. 4. Sensor according to claim 1, in which the element is surrounded by a layer for reflecting the luminescence radiation. 5. Sensor according to cliam 1, in which the element has an elongated shape along the element axis and is a cylinder of revolution about this axis and the sensor further comprises a luminescence radiation reflector, wherein the first screen is placed between this reflector and the first extremity of the element, the second extremity of the element configured to be optically coupled to the light guide, the second screen extending along a length of the element from the second extremity of this element, this length depending on the geometry of the element. 6. Sensor according to claim 1, in which the radiation detection material is chosen among the group comprising phosphate type radiophotoluminescent glasses, photo-chromic type luminescent glasses, crystalline radiation detection materials, alumina in the a phase, scintillating crystals and crystals configured to emit an optically stimulated luminescence. 7. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation; andfirst and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element,wherein this sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation, the material is configured to emit said luminescence radiation when the material is optically stimulated, the sensor is thus an optically stimulated luminescence radiation sensor, and the light guide is configured to convey a radiation for optically stimulating the element and for illuminating this element with the optically stimulating radiation. 8. Sensor according to claim 7, in which the material has an effective atomic number close to 10. 9. Sensor according to claim 7, in which the axis of the element is an axis of symmetry of revolution for this element. 10. Sensor according to claim 7, in which the element is surrounded by a layer for reflecting the luminescence radiation. 11. Sensor according to claim 7, in which the element has an elongated shape along the element axis and is a cylinder of revolution about this axis and the sensor further comprises a luminescence radiation reflector, wherein the first screen is placed between this reflector and the first extremity of the element, the second extremity of the element configured to be optically coupled to the light guide, the second screen extending along a length of the element from the second extremity of this element, this length depending on the geometry of the element. 12. Sensor according to claim 7, in which the radiation detection material is chosen among the group comprising phosphate type radiophotoluminescent glasses, photo-chromic type luminescent glasses, crystalline radiation detection materials, alumina in the αphase, scintillating crystals and crystals configured to emit an optically stimulated luminescence. 13. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation;first and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element, and the sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation; anda body comprising a cavity in which the at least one element is located and whose wall is configured to reflect the luminescence radiation, as well as a part comprising a boring whose axis is the axis of the at least one element and whose wall is configured to reflect the luminescence radiation, this part being configured to collect this radiation and to convey the radiation to the entry of the flexible light guide, under an angle that is compatible with the numerical aperture of this flexible light guide, when this guide is coupled to the sensor. 14. Sensor according to claim 13, in which the boring has a conical shape. 15. Sensor according to cliam 13, further comprising a focalisation lens between the at least one element and the boring in the part. 16. Radiation sensor for dosimetry, comprising:at least one element made out of a radiation detection material, wherein this element has first and second extremities and an axis which passes through these first and second extremities, and the material is configured to emit a luminescence radiation and is transparent to this luminescence radiation;first and second radiation filter screens, wherein the first screen is placed opposite the first extremity of the element and is configured to filter the radiation that reaches the element along a direction close to the axis of the element, the second screen is thicker than the first screen, and this second screen is placed at the periphery of the element and is configured to filter the radiation that reaches the element along a direction close to a direction that is perpendicular to the axis of the element, and the sensor is configured to be optically coupled to a flexible light guide configured to collect and convey the luminescence radiation; anda laser configured to emit a radiation for stimulating the element made out of radiation detection material and means for detecting the luminescence radiation emitted by this element. 17. Device according to claim 16, further comprising:a first photo-detector, reflector configured to allow less than 10% of the radiation emitted by the laser to pass towards this first photo-detector and configured to reflect more than 90% of this radiation towards the flexible light guide and a second photo-detector configured to detect the luminescence radiation emitted by the element and conveyed by the flexible light guide, wherein the ratio of signals provided by the first and second photo-detectors allows the variations in the stimulation radiation effectively transmitted to the element to be measured each time this element is interrogated.
042382882	abstract	According to the invention, the drive of a nuclear reactor's control element comprises an electromotor having a stator and a rotor composed lengthwise of two parts whose total length is equal to that of the active part of the stator. One part of the rotor is a solid cylinder-shaped member. The other part of the rotor comprises at least three double-arm rocking levers, the pivot axes of which are parallel to the axis of a drive screw. One arm of each of said levers is a rotor pole. The other arm of each of said levers carries a roller, the axis of rotation of which is parallel to the axis of the drive screw. Said rollers make up a detachable roller nut which interacts with the drive screw under the action of an electromagnetic field.
053032713	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a steam generator 1, comprising an outer casing 2 of generally cylindrical shape, the upper part of which has a larger diameter than the lower part, a tube plate 3, in which the end parts of tubes 5 of the bundle 4 of the steam generator are fastened, and a water box 7 delimited by a hemispherical casing, through which connection pieces 6a and 6b pass on either side of a partition 8 separating the water box 7 into two parts. The tube plate 3 is fastened to the lower part of the outer casing 2 which delimits the secondary part of the steam generator containing the bundle 4. The hemispherical casing of the water box 7 is fastened under the tube plate and constitutes the primary part of the steam generator communicating with the inner space of the tubes 5 of the bundle 4. The bundle 4 is located inside a bundle casing 9 placed coaxially within the outer casing 2. Feed water is introduced into the secondary part of the steam generator by way of a connection piece 11 passing through the outer casing 2 above the upper part of the bundle 4. The feed water entering by way of the connection piece 11 circulates in an annular space 13 provided between the outer casing 2 and the bundle casing 9, so as to arrive at the lower part of the bundle casing 9 located above and at some distance from the upper face of the tube plate 3. The feed water penetrates into the bundle casing by way of the orifice formed between the lower end of the bundle casing 9 and the tube plate 3 and putting the annular space 13 in communication with the internal volume of the bundle casing 9. The feed water comes into contact with the tubes 5, heat up in contact with the tubes in which the primary water circulates, and circulates in the vertical direction from the bottom within the bundle casing and in contact with the tubes 5. The heat exchange between the primary water and the feed water via the walls of the tubes 5 ensures the heating and then evaporation of the feed water, the steam formed being dried in the part of the steam generator located above the bundle 4 and then being discharged by way of the connection piece 12 located at the upper end of the casing 2 of the steam generator. Each of the tubes 5 of the bundle 4 communicates with a first part of the water box 7 at one of its ends and with a second part of the water box at its other end. This ensures circulation of the primary water within the tubes of the bundle. The tubes 5 of the bundle 4, which are bent in the form of a U in their upper part and which are held by horizontal spacer plates 10 uniformly spaced over the height of the bundle, are arranged in such a way as to form vertical parallel rows and a regular network of circular cross-section in the horizontally directed transverse planes. The bundle as a whole has the form of a volume rotationally symmetrical about the vertical axis of the steam generator, delimited in its upper part by a hemi-spherical surface. As can be seen in FIG. 2, a small-size orifice 15 or handhole passes through the outer casing 2 of the steam generator in the lower part of the annular space 13 provided between the bundle casing 9 and the outer casing 2. The carrier device according to the invention, which will be described hereinafter, makes it possible to displace a televisual inspection means or a tool along the entire circumference of the bundle 4, for example in order to conduct a check or an examination of the part of the tubes 5 which is located between the lower end of the bundle casing 9 and the upper face 3b of the tube plate 3. This examination of a part of the tubes which is liable to experience severe corrosion as a result of the accumulation of chemical compounds above the tube plate can be carried out by way of the annular orifice 14 putting the annular space 13 in communication with the internal volume of the bundle casing 9. The means for carrying out attendance work inside the steam generator have to be introduced by way of the handhole 15 passing through the outer casing 2. FIG. 3 shows a first embodiment of movable carrier device according to the invention in a first alternative embodiment. The carrier device 18, has been shown inside the secondary part of a steam generator which is represented schematically by the lower edge 9a of the bundle casing 9 and by the inspection orifice or handhole 15. The device 18 comprises a central body 20 carrying a fastening head 21 consisting of an inflatable flexible envelope in two parts of substantially cylindrical shape, and two jacks 22a, 22b placed in transverse arrangements on either side of the central body 20 and each carrying a respective inflatable flexible head 23a, 23b. The inflatable flexible head 21 placed in a central location in relation to the heads 23a and 23b is carried by a jack 24, the rod of which is perpendicular to the rods of the jacks 22a and 22b. When the device 18 is in position inside the secondary part of a steam generator in the annular space 13 between the bundle casing and the outer casing, the rod of the jack 24 extends vertically and the rods of the jacks 22a and 22b extend horizontally and are inclined slightly relative to one another, as can be seen in FIG. 4. The central body 20 also carries, opposite to the jack 24 and to the flexible head 21, a guide assembly 25 comprising two arms 25a and 25b consisting of flexible metal leaves, such as spring leaves, fastened in a position inclined relative to the central axis 22' of the carrier, on either side of this central axis which is vertical when the carrier device 18 is in operation inside the steam generator. Each of the arms 25a and 25b carries, at its end opposite its fastening on the central body 20, a roller 26a (or 26b) mounted rotatably at the end of the corresponding arm and bearing against the lower edge 9a of the bundle casing 9, as can be seen in FIG. 5. As can be seen in FIG. 6, the jacks 23a, 23b and 24 are integrated in the central body 20 which comprises a first chamber 28 of vertical axis, in which the piston 24' of the jack 24 is mounted and which is closed by means of a piece 29 screwed into the central body 20 and having a gasket. The rod of the piston 24' of the jack 24 is mounted vertically slidably and sealingly on the inside of the piece 29. The central body 20 comprises a second chamber 30 of horizontal axis, in which the pistons 22'a and 22'b of the jacks 22a and 22b are mounted slidably and which is closed at it ends by means of closing pieces 31a and 31b, in which the rod of the jack 22a and the rod of the jack 22b are respectively mounted sealingly slidably. The jacks 22a and 22b constitute a double jack, the pistons and rods of which are displaced in opposite directions when the double jack is supplied with hydraulic fluid. The rods of the jacks are displaced with to the right, in which case the rod of the jack 22a assumes a retracted position and the rod of the jack 22b an extended position, or to the left, in which case the rod of the jack 22a assumes an extended position and the rod of the jack 22b a retracted position. As will be explained later, the mutually opposed displacement of the two jacks makes it possible to obtain the displacement of the carrier in a circumferential direction of the annular space of the steam generator. The rod of the jack 24 is displaced between an extended high position and a retracted low position. The flexible envelopes 21, 23a and 23b, which can be fastened removably to the end of the rods of the jacks 22a, 22b and 24 by means of a dovetail joint, comprise a support allowing articulated mounting on the rod of the corresponding jack. The envelope 21 is mounted on the rod of the jack 24 in an articulated manner about an axis having a first direction, and the envelopes 23a and 23b are mounted on the rods of the respective jacks 22a and 22b in an articulated manner about an axis having a second direction perpendicular to the first. When the carrier device is in place in the annular space of the steam generator, as shown in FIG. 3, the first direction is horizontal and the second direction is vertical. Each of the envelopes 21, 23a and 23b is produced in double form and comprises two compartments of cylindrical shape constituting balloons inflatable by means of solenoid valves and of a compressed-air supply circuit. The arms 25a and 25b constituting the means for guiding the carrier on the lower end of the bundle casing consist of flexible metal leaves which are mounted in an articulated manner on the body 20 so as to form a compass mechanism which can be in the open position, as shown in FIG. 3, or in the closed position. In the open position of the compass mechanism, the arms 25a and 25b are spaced apart and form a particular angle, so that the guide rollers 26a and 26b are spaced at some distance from one another. The arms 25a and 25b are maintained in this spaced-apart position by an assembly 33 of two links on one another and articulated on the arms 25a and 25b. In the folded-up position of the compass mechanism, the arms 25a and 25b are parallel and laid against one another. Reference will now be made to FIGS. 3 to 6 as a whole in order to describe the operation of the movable carrier device according to the invention. To put the carrier in place in the steam generator, the flexible envelope 21 is introduced in the contracted state into the annular space 13 of the steam generator by way of the handhole 15. The envelope 21 is placed in a position located above the handhole 15 and inflated by means of compressed air, thus ensuring that it expands and is fastened in place by wedging in the annular space 13. The central body 20 and the guide means consisting of the arms 25a and 25b are then introduced into the annular space of the steam generator by way of the handhole 15. To carry out this introduction of the central body and of the arms 25a and 25b, the arms 25a and 25b are placed in their folded position, thus allowing them to be introduced in the vertical direction by way of the handhole by utilizing the flexibility of the spring leaves forming these arms. The arms 25a and 25b and the central body 20 of the carrier are engaged into the handhole by downward displacement in the vertical direction. The envelopes 23a and 23b are fastened to the ends of the rods of the respective jacks 22a and 22b in succession and level with the handhole 15 by means of their support. The connections of the fluid circuits between the inflatable envelopes and the central body are made. The whole of the central body 20, of the guide device 25 and of the flexible envelopes 23a and 23b is then displaced upwards, so as to carry out the fastening of the central body 20 on the support of the envelope 21 by means of the rod of the jack 24, the opening of the arms 25a and 25b and then the blocking in the open position by means of the links 33. The jack 24 is actuated so as to exert a pull upwards in the vertical direction on the central body 20 and to bring the guide rollers 26a and 26b to bear on the lower edge 9a of the bundle casing 9. The envelopes 23a and 23b are then displaced simultaneously to the right or to the left, depending on the direction of displacement desired for the carrier, by use of the double jack 22a, 22b. During this displacement, the envelopes 23a and 23b are in their contracted state. The envelopes 23a and 23b are then supplied with compressed air, so as to ensure the inflation of the envelopes and the wedging of these in the annular space 13 between the bundle casing and the outer casing of the steam generator. The flexible envelope 21 is then put into its contracted position by the discharge of the compressed air which it contained. The double jack 22a, 22b is fed in the opposite direction to the preceding one, thereby causing a displacement of the carrier as a whole either to the right or to the left, depending on the desired direction of displacement, in relation to the envelopes 23a and 23b and to the rods of the jacks 22a and 22b which are maintained in a position fixed relative to the steam generator. The movable carrier can thus be displaced one step in the circumferential direction of the steam generator in one direction or the other. The next displacement step will be carried out by obtaining the inflation and wedging of the flexible envelope 21, then the deflation and displacement of the envelopes 23a and 23b in the desired direction, the inflation of these envelopes in their new position, and finally the displacement of the central body 20 by the feed of the double jack. Between two advancing steps, it is possible to raise the central body by means of the jack 24 so as to lay the rollers 26 against the bottom of the bundle casing 9. As can be seen in FIG. 4, during the circumferential displacements of the carrier, the articulated mounting of the lateral envelopes 23a and 23b about the vertical axes makes it possible to follow the curvature of the annular space 13 of the steam generator. As a result of successive displacements controlled remotely by hydraulic and pneumatic means, the carrier and therefore the tool or inspection device fastened to this carrier can be arranged in any circumferential position in relation to the tube bundle of the steam generator. It is consequently possible to conduct a televisual inspection or attendance work in any zone of the periphery of the bundle. The inspection means or the tool is introduced into the zone occupied by the bundle by way of the annular orifice 14 located between the lower end 9a of the bundle casing 9 and the tube plate 3. FIGS. 7, 8 and 9 illustrate an alternative embodiment of the carrier device according to the invention. In this version, the central body 40 carries two jack bodes 41 and 42 by means of joints and in a V-shaped arrangement, the jack bodies being inclined slightly relative to the horizontal plane and forming an angle larger than 120.degree. with one another. The jacks 41 and 42, which are arranged on either side of the central body 40, comprise respective rods 41a and 42a directed outwards and carrying at their end, in an articulated manner, respective supports 43a, 43b of two flexible envelopes 44a and 44b. The supports 43a and 43b are each fixed to a guide arm 45a, 45b respectively carrying at its end a respective roller 46a, 46b intended for ensuring the guidance of the carrier on the lower edge 9a of the bundle casing 9. The central body 40 likewise carries an inflatable flexible envelope 48 by means of a support 49 which can be joined removably to the carrier 40. The jack bodes 41 and 42 mounted in an articulated manner on the central body 40 are maintained in a raised position by two supporting pieces 51a and 51b articulated on the central body 40 and maintained in a spacing-apart and raising position by a helical spring 50. The inflatable envelopes 44a, 44b and 48 are similar to the envelopes 21, 23a, and 23b which are illustrated in FIGS. 3 and 4 and which were described above. The operating mode of the device shown in FIGS. 7, 8 and 9 will be described hereinafter. In a first stage, the inflatable flexible envelope 48 is introduced in the contracted and deflated state into the annular space 13 by way of the handhole 15, until it assumes a position slightly above the handhole, as shown in FIG. 7. The flexible envelope 48 is then expanded by inflation with compressed air, thus ensuring that it is wedged in the annular space 13 in the position shown. The central body 40 is then put in place and joined to the support of the flexible envelope 48 by means of a dovetail joint. The flexible envelope 48 is then deflated, and the whole of the flexible envelope 48 and of the central body 40 is displaced manually either to the right or to the left, in order to free the handhole 15, while at the same time leaving the lateral part of the central body 40 having one of the jack supports 51a or 51b accessible. The flexible envelope 48 is then expanded by inflation with compressed air. The introduction of an assembly consisting of a jack 41 or 42, of an inflatable envelope 44a or 44b and of a guide arm 45a or 45b carrying a roller 46a or 46b into the annular space 13 of the steam generator by way of the handhole 15 is carried out. The flexible envelope 44a or 44b is in the contracted and deflated state during this introduction operation. The assembly consisting of the jack, the flexible envelope and the guide arm is then fixed on the central body 40 and the corresponding support 51a or 51b. The newly formed assembly is then displaced in the direction opposite to the preceding one, after the flexible envelope 48 has been deflated, so as to free the entrance of the handhole 15. The second assembly consisting of a jack, of a flexible envelope 44a or 44b and of a guide means 45a or 45b is assembled together. This installation is made easier by the fast that the arms 45a and 45b consist of spring leaves. The rollers 46a and 46b are then brought into contact with the lower edge 9a of the bundle casing 9 by simultaneous actuation of the jacks 41 and 42 in opposite directions, the flexible envelopes 44a and 44b being in the deflated state. The supporting pieces 51a and 51b make it possible to carry out the raising of the jack bodies, of the envelope supports and of the arms 45a and 45b as a result of the action of the helical spring 50. The displacement of the carrier in the circumferential direction is obtained by putting the flexible envelopes 44a and 44b into their expanded state and the central flexible envelope 48 into the contracted and deflated state. Simultaneous actuation of the jacks 41 and 42 in opposite directions ensures circumferential displacement of the central body 40 in relation to the envelopes 44a and 44b maintained in a fixed position by wedging inside the annular space. The displacement of the central body 40 can be carried out in one direction or the other, depending on which jack is extended and which jack is retracted. The expansion of the central flexible envelope 48 by inflation and the contraction of the lateral flexible envelopes 44a and 44b by deflation are then carried out. The two jacks 41 and 42 can then be actuated simultaneously in the direction opposite to the preceding one, so as to return them to the initial position in order to execute a new displacement step. As before, therefore, it is possible to obtain any circumferential position of the carrier around the bundle as a result of a displacement in successive steps which is controlled remotely by hydraulic and pneumatic means. During all these displacements, the carrier is guided by the rollers which are maintained in contact with the lower end of the casing of the bundle and which are displaced on the latter. At all events, it is possible to displace the carrier in a fully automated way on the inside of steam generators, in order to conduct a check or attendance work in any part of the bundle of the steam generator. The central body, the actuating jacks and the deformable flexible envelopes may have forms and arrangements different from those described as examples. Likewise, the guide assembly of the carrier can be produced in a different form. The rolling means of this guide assembly can be displaced not only on the lower end of the bundle casing, but also by bearing on the tube plate. Finally, the carrier device according to the invention can be used in any steam generator comprising a bundle surrounded by a bundle casing arranged coaxially so as to provide an annular space located between the bundle casing and the outer casing.
	description	Throughout this disclosure, including in the claims, the expression xe2x80x9cbeam control dataxe2x80x9d denotes data (whether in vector format or pixel format) that directly determines a configuration (or sequence of configurations) of beam control hardware that in turn determines what pattern is imaged on a target by a pattern generation system in response to a set of image data. The pattern generation system of the invention receives raw image data and generates beam control data in response thereto, typically with an intermediate step of generating optimized hierarchical image data from the raw hierarchical data, and generating the beam control data in response to the optimized hierarchical image data. The term xe2x80x9coptimizedxe2x80x9d is used in a broad sense to denote xe2x80x9cimprovedxe2x80x9d (e.g., embodying an improved combination of properties, such as reduced data volume to be transferred to the graphics engine, and ability to be converted to beam control data with acceptably low processing time) as well as xe2x80x9cimproved to the maximum degreexe2x80x9d (e.g., embodying the best possible combination of the relevant properties). In one example, the pattern generation system of the invention receives and rasterizes a set of hierarchical image data (indicative of a two-dimensional bit map) to generate a set of beam control data (in pixel format) determining a sequence of pixels to be written to the target during a raster scan. One aspect of the inventive method is a method for generating beam control data in response to hierarchical image data. In a class of preferred embodiments, the invention rasterized hierarchical image data indicative of hierarchical CAD designs, such as designs in the conventional GDS-II format. A hierarchical design groups together (in an entity known as a xe2x80x9ccellxe2x80x9d) data indicative of a feature (or set of features) that is to be repetitively placed in different positions on the layout (e.g., by iterating over the cell with appropriate offsets indicative of different locations on the layout). A cell of a hierarchical design can be xe2x80x9csimplexe2x80x9d in the sense that it consists of data that determines a repeated feature or feature set (but does not include or refer to another cell), or it can be xe2x80x9ccomplexxe2x80x9d in the sense that it includes a reference to another cell (which other cell can, but need not, be included within the complex cell) and optionally also data that determines a repeated feature or feature set (without including or referring to another cell). A set of hierarchical image data includes one or more xe2x80x9cprimaryxe2x80x9d cells (each determining a feature or feature set that is repeated on the layout), and also additional data. The additional data includes data indicative of non-repeated features of the layout, and data referring to primary cells. Each primary cell can itself include references to one or more cells (denoted herein as secondary cells). Similarly, each secondary cell can include references to one or more cells (denoted herein as tertiary cells), and so on for higher levels of the hierarchy. If no primary cell includes a reference to a secondary cell, we shall refer to the overall set of hierarchical data as xe2x80x9ctwo-levelxe2x80x9d hierarchical data (which determines a layout having two-level hierarchy). If at least one primary cell includes a reference to a secondary cell, we shall refer to the overall set of hierarchical data as xe2x80x9cN-levelxe2x80x9d hierarchical data (where N is greater than two) which determines a layout having N-level hierarchy. In contrast with hierarchical image data, xe2x80x9cflatxe2x80x9d format image data (determining a xe2x80x9cflatxe2x80x9d layout) includes no primary cell. The expression xe2x80x9ccell instantiationxe2x80x9d is used herein to denote a reference to a cell indicating that the cell is to be copied to a particular location on the layout. Such location is typically denoted by an offset. Hierarchy becomes inevitable due to the increasing number of features in typical IC layouts, the shrinking size of critical dimensions of typical features (e.g., gate size) and the need to process correction management schemes that try to facilitate the physical reduction of critical dimensions by adding serifs and scatter bars. Hierarchical design reflects the congruent structure of repetitive building blocks of IC layout. A DRAM or FPGA (field-programmable gate array) device, for example, can define a flat-format count greater than 109 features. With 8 to 10 bytes per geometry, such a design, when implemented with a flat layout, imposes hard bandwidth problems when raw image data indicative of the design is communicated from a storage device to a raster engine. The inventors have recognized that it would be desirable to implement such a design as a hierarchical design (typically having N-level hierarchy, where N is greater than two) rather than a flat design, since the only new piece of information per cell instantiation is the cell""s offset on the layout, so that communicating this offset is enough. Compaction factors of hierarchical designs scale proportionally with the number of cell instantiations. Therefore communicating a cell only once to a graphics engine (along with the relevant offset per instantiation) decreases the required communication bandwidth dramatically. The trend of growing file size for lithographic data is likely to outpace the increase of data transfer rates in pattern generation systems used for lithography. Relying on ample processing power and larger available memories rather than on fast transfer rates offers a robust and workable paradigm. The inventors have recognized that it is therefore desirable to reduce the data volume that must be transferred to graphics engines of pattern generation systems such that chunks of repeated data are transferred only once to a graphics engine and kept in memory of the graphics engine until each chunk is repeatedly referred to. In typical embodiments, the present invention browses the hierarchical data structure of image data (which can be in GDSII format) which contains geometry data determining a pattern to be imaged on a target, and identifies the most significantly repeated cells of image data. The image data is then compressed in the sense that each of its most significantly repeated cells is transferred only once to the graphics engine (for caching in memory of the graphics engine). Subroutine call commands are also transferred to the graphics engine so that the graphics engine can process the subroutine call commands to retrieve each cached cell from memory more than once (at appropriate times). The graphics engine thus inflates the compressed data transferred to it in accordance with the invention, typically with a large inflation factor due to the typically high number of instantiations of cached cells. Transferring this data only once, caching a subset of the transferred data in the graphics engine, and recalling the cached data repeatedly unclogs the download bottleneck. More specifically, the present invention decreases the volume of image data that must be transferred to a graphics engine (e.g., raster engine) by determining a set of N-level hierarchical image data, where N is greater than one (preferably N is greater than two), transferring the hierarchical image data to the graphics engine (xe2x80x9cGExe2x80x9d), and caching cells of the hierarchical image data in a memory of the GE. The GE executes subroutine call commands in response to elements of the hierarchical image data, which can be either portions of cached cells, or non-cached elements of the hierarchical image data. Each subroutine call command retrieves a cached cell (from memory of the GE) and generates beam control data (for imaging a pattern determined by the cell, at a location on the target indicated by an offset) in response to the retrieved cached cell and data indicative of the offset. In preferred embodiments, the beam control data is in pixel format, but it can alternatively be in vector format. A preferred embodiment of the invention will be described with reference to FIG. 1. The system of FIG. 1 is programmed and otherwise configured to perform a print job in which it images a pattern on target 8 in response to a set of hierarchical raw image data. Target 8 is typically a mask (e.g., a piece of chrome-coated quartz glass) which can be used to produce an integrated circuit after it has been patterned as a result of such a print job. The FIG. 1 system includes beam system 6, and a pattern generation system comprising image data generation system 2 and graphics engine 4. Beam system 6 can project a beam (an electron beam or laser beam) on target 8 to image a spot thereon, and can sweep the beam along a raster scan path relative to target 8 to image a sequence of pixels thereon. Target 8 can be mounted on a movable stage (not shown), so that motion of both the stage and the beam can be controlled to cause the beam to sweep along the raster scan path in the target""s frame of reference. Image data generation system 2 is configured to generate a set of optimized hierarchical image data in response to a set of hierarchical raw image data indicative of the pattern to be imaged on target 8. System 2 is typically implemented as a programmed processor, and thus is sometimes referred to below as xe2x80x9cprocessorxe2x80x9d 2. In a preferred implementation, graphics engine 4 is a raster engine (including memories 10 and 11 and processor 12) which is coupled to receive the optimized hierarchical image data from processor 2, and configured to store at least one cell of the optimized hierarchical image data in memory 10, generate beam control data (or a precursor thereto) in response to the optimized hierarchical image data (including by retrieving stored data from memory 10), store beam control data (or a precursor to beam control data) in memory 11, and retrieve beam control data from memory 11 (or retrieve the precursor data from memory 11 and generate beam control data in response thereto) and send the beam control data to beam system 6 (or generate the beam control data and send it directly to system 6 without storing it, or a precursor thereto, in memory 11) to cause system 6 to execute a raster scan of the beam relative to target 8. The beam control data asserted by the pattern generation system of FIG. 1 to system 6 is in pixel format. However, it is contemplated that alternative embodiments of the invention will generate beam control data having vector format. Processor 12 of raster engine 4 is programmed to execute a subroutine call in response to each element of the hierarchical image data (to be referred to as a xe2x80x9csubroutine call commandxe2x80x9d) indicating that an identified cell should be retrieved from memory 10 and identifying a location on the target at which (or beginning at which) a pattern determined by such cell should be imaged. The subroutine call command typically identifies the location on the target by identifying an offset value that determines a location in the pattern to be imaged, and the latter location corresponds to the location on the target. Each subroutine call command can be a portion of a cached cell being retrieved from memory 10 (e.g., when a primary cell being retrieved includes a subroutine call command indicating that a secondary cell should be retrieved before the rest of the primary cell is retrieved) or it can be a non-cached portion of the optimized hierarchical image data. In typical implementations, each subroutine call command includes data indicative of an offset (from a single identified location of the overall pattern to be imaged on target 8), and causes processor 12 to retrieve a cached cell from memory 10 and generate beam control data (for imaging a pattern determined by the cell at, or beginning at, the location indicated by the offset) in response to the retrieved cell. In alternative implementations of the FIG. 1 system, processor 12 generates a cell of beam control data in response to each cell of optimized hierarchical image data transferred to raster engine 4 from processor 2, and raster engine 4 caches the cell of beam control data in memory 10 or 11 rather than the corresponding cell of image data received from processor 2. Each cached beam control data cell remains statically in the memory throughout the entire lifetime of a print job. Subroutine call commands for each cached cell of beam control data are distributed throughout each set of optimized hierarchical image data received from processor 2, and each subroutine call executed by raster engine 4 in response to one such command retrieves a cell of beam control data from memory 10 (or 11) and causes beam system 6 to image a pattern determined by the retrieved cell on target 8 beginning at a location determined by the command (i.e., a location determined by an offset included in the command). In one class of implementations of the FIG. 1 system, processor 2 is programmed with software for generating optimized two-level hierarchical image data in response to two-level hierarchical raw image data (raw image data having primary cells but no secondary cell), and such software refers to variables and constants defined as follows: total number of geometries defined by the entire set of image data: TGC; cell""s bounding box extent: CEX; number of instantiations of a cell (within the entire set of image data): CNI; cell""s local figure count, including arrayed primitives: CFC; cell""s percentage of the total size (volume) of the entire set of image data in which it is instantiated: CPO=(CNI)(CFC)/TGC; residual flat output for the entire set of image data: RFO=[1xe2x88x92xcexa3CPO]TGC, where the summation is over all analyzed cells; cell""s equivalent memory: CEM=axc3x97CFC (where a is a constant. In one implementation, a=8); cell""s output due to its encoded instantiations (i.e., the volume of data, to be included in the optimized hierarchical image data, that is required to call the cell repeatedly (after the cell has been cached in the GE) to implement all instantiations of the cached cell): CIO=bxc3x97CNI (where b is a constant. In one implementation, b=12); GE memory available (i.e., the size of that portion of memory 10 of raster engine 4 available for caching): GEM; library output (i.e., volume of the non-cached xe2x80x9ccall-dataxe2x80x9d portion of the total set of optimized hierarchical image data, which is employed to implement all calls of each cached cell of the optimized hierarchical image data. The call-data includes all subroutine call commands which refer to cached cells): LO=xcexa3CIO summing over all analyzed cells; projected size of entire set of optimized hierarchical image data, not including the cells thereof to be cached: PFS=LO+RFO; and maximum size of the set of optimized image data to be transferred to the GE (not including the cells thereof to be cached): FSL (for example, FSL can be 13 Gbytes). Processor 2, when programmed with the noted software, performs the following operations in the indicated sequence to generate a set of optimized two-level hierarchical image data in response to a set of two-level hierarchical raw image data: 1. Begin: identify the hierarchy graph determined by the hierarchical raw image data, and build an indexing structure which sorts the cells of the raw image data with respect to the CPO of each cell. 2. Starting with the cell having the highest CPO which has not previously been analyzed, go to step 3 if CEMxe2x89xa6GEM, or if CEM greater than GEM for all cells go to End (i.e., do not include any cell of the raw image data as a cell (to be cached) of the optimized image data). 3. For each cell for which CEMxe2x89xa6GEM, calculate CIO. Then, if LO+CIO less than FSL go to step 5 else continue to step 4. 4. Create a new cell that contains as many instantiations of the current cell as possible, to reduce CIO. 5. Check the extent of the cell (the old cell""s extent if step 5 follows step 3, or the new cell""s extent if step 5 follows step 4) for library encoding (by checking that CEM for the cell satisfies CEMxe2x89xa6GEM), and if necessary (i.e., if CEM for the cell is greater than GEM) break the cell into multiple cells. 6. Update GEM (the amount of available GE memory) and LO (the library output). 7. Calculate the projected size (xe2x80x9cPFSxe2x80x9d) of the entire set of optimized image data (not including the cells thereof to be cached), and if PFS greater than FSL go to step 2 else continue to step 8. 8. End. For example, in step 4, a list of 40xc3x9740 of the current cell""s instantiations can be grouped into the new cell. This can be implemented in a manner that depends on the proximity of the instantiations. Such grouping of many smaller cells into one larger cell reduces the number of instantiations of cells in the final version of the optimized image data by large factor (by a factor of 1600, for example to 2.8xc3x97106 instantiations from an original 4.47xc3x97109 instantiations). Thus, the size of the resulting set of the residual (noncached) portion of the optimized hierarchical image data can be reduced accordingly to a manageable size. In other preferred implementations of the FIG. 1 system, processor 2 is programmed with software for generating optimized N-level hierarchical image data (where N is any integer greater than one) in response to M-level hierarchical raw image data (where M is any integer greater than one). In some such embodiments, the processor 2 attempts to group into a two level hierarchy the four cells of the raw image data having the largest Cell Percentage Output (above-defined CPO). In general, by increasing the number of hierarchical levels of the optimized N-level hierarchical image data (which contains cells to be cached in GE memory) generated from a set of hierarchical raw image data, the volume of the optimized hierarchical image data to be transferred to the graphics engine is decreased Preferably, processor 2 is programmed to postpone the flattening of the set of optimized hierarchical image data it generates, where xe2x80x9cflatteningxe2x80x9d in this context denotes determination of the sequence in which each of the cells (or sub-cells) of the set of optimized data, and the data comprising the residual portion of the set of optimized data, is transmitted to raster engine 4. Also preferably, processor 2 is programmed to map arrays to an xe2x80x98arraying operatorxe2x80x99, which is passed down from the lowest hierarchical level (the xe2x80x9ctrunkxe2x80x9d) to the highest hierarchical level (a primitive). Cells at any point of the browsing (during generation of optimized hierarchical image data in response to raw image data) fully contain their embedded sub-tree. When processor 2 handles a cell, this is equivalent to handling the entire sub-tree contained in the cell. This facilitates a natural encoding of more than one level of hierarchy into the optimized hierarchical image data. We next describe a preferred embodiment of software for programming processor 2 to generate optimized hierarchical image data in response to hierarchical raw image data. For purposes of this example, consider a cell (xe2x80x9cCell_Axe2x80x9d) which refers to N_g geometries and N_c cells, and assume that the optimized hierarchical image data includes a set (xe2x80x9cHIxe2x80x9d) of xe2x80x9ccxe2x80x9d of such cells where xe2x80x9ccxe2x80x9d is an integer: HI={Cell_Axe2x80x941xe2x88x92Cell_A_N_c}. Also assume that each cell in HI refers to at least one geometry (i.e., N_g is greater than zero for each cell in the set), and that each cell in set HI occurs at least twice in the total set of optimized hierarchical image data. To characterize the optimized hierarchical image data with a two-level hierarchy, the software would (for each Cell_A_i) aggregate the cell""s N_g geometries into a number of frames, each of which is intended to cover a specific area (e.g., an area of size 40 by 40 microns) on the target, and the software would generate the optimized hierarchical image data as the set HI of cells (each cell comprising a sequence of frames) together with a set of residual data. The residual data comprises non-repeated data (which can also be aggregated into frames) that is not included in any of the cells of set HI, and also xe2x80x9ccall-dataxe2x80x9d that determines each instantiation of each of the cells in the coordinate system of the entire set of optimized hierarchical image data. The call-data preferably includes a subroutine call command for each instantiation of a cell, including an offset for each instantiation of each cell in the coordinate system of the entire set of optimized hierarchical image data, and an absolute address to each cell to be called (an address for the list of geometries comprising the cell). To generate three-level optimized hierarchical image data in response to raw image data having a three-level hierarchy, the software would (for each Cell_A_i) identify at least one sub-cell (i.e., a xe2x80x9csub-cellxe2x80x9d set comprising at least one sub-cell), where each sub-cell in the sub-cell set occurs repeatedly within the cell. The software would characterize the cell by the following data: the sub-cell set; and a set of residual cell data comprising non-repeated data of the cell (which non-repeated data can be aggregated into frames) and call-data that determines each instantiation of each sub-cell within the cell. The software would generate the entire set of optimized hierarchical image data as: data (to be cached) determining all the sub-cells (of all the cells of set HI), residual cell data to be cached (xe2x80x9cfirst residual cell dataxe2x80x9d), and a set of additional residual data. The first residual cell data determines the set (HI) of cells, each of the cells comprising a sequence of subroutine call commands and cell residual data, each of the subroutine call commands being for instantiation of one of the cached sub-cells, and the cell residual data for a cell comprising the non-repeated data of the cell. Typically, the first residual cell data comprises a sequence of subroutine call commands (for instantiating cached sub-cells) interspersed with cell residual data of one of the cells, followed by more subroutine call commands (for instantiating cached sub-cells) interspersed with cell residual data of another one of the cells, and so on. Typically, each of the subroutine call commands of the first residual cell data determines an offset for instantiation of a sub-cell in the coordinate system of one of the cells (the xe2x80x9ccalling cellxe2x80x9d) of set HI, and an absolute address to each sub-cell to be called (an address at which the list of geometries comprising the sub-cell is cached). The set of additional residual data (which is not to be cached) comprises non-repeated data of the optimized hierarchical set of image data which is not part of any cell of set HI (the non-repeated data can be aggregated into frames), and also call-data which determines each instantiation of each cell in the total set of optimized hierarchical image data. The call-data preferably includes a subroutine call command for each instantiation of a cell, including an offset for each instantiation of the cell in the coordinate system of the entire set of optimized hierarchical image data, and an absolute address to each cell to be called (an address for the list of geometries and subroutine call commands comprising the cell). In response to each subroutine call command of the call-data, the GE retrieves a cached cell, sequentially executes the subroutine call commands of the retrieved cell, and intersperses the data of each sub-cell retrieved in response to one of the subroutine call commands of the retrieved cell with the cell residual data of the retrieved cell. Alternatively, to generate two-level optimized hierarchical image data in response to raw image data having a three-level hierarchy, the software would (for each Cell_A_i) identify at least one sub-cell (i.e., a xe2x80x9csub-cellxe2x80x9d set of at least one sub-cell), where each sub-cell in the sub-cell set occurs repeatedly within the cell, and the software would characterize the cell by the following data: the sub-cell set; and a set of residual cell data. The residual cell data would comprise non-repeated data of the cell (which non-repeated data can be aggregated into frames) and also call-data that determines each instantiation of each sub-cell within the cell. The software would generate the entire set of optimized hierarchical image data as: data (to be cached) determining all the sub-cells (of all the cells of set HI); and a set of residual data, where the set of residual data comprises the residual cell data for each cell of set HI (this residual cell data can be aggregated into frames), non-repeated data which is not part of any cell of set HI (the non-repeated data can also be aggregated into frames), and revised call-data (derived from the call-data of each cell and call-data of the raw image data). The revised call-data determines each instantiation of each sub-cell in the total set of optimized hierarchical image data. The revised call-data preferably includes a subroutine call command for each instantiation of a sub-cell, including an offset for each instantiation of each sub-cell in the coordinate system of the entire set of optimized hierarchical image data, and an absolute address to each sub-cell to be called (an address for the list of geometries comprising the sub-cell). The above-described methods for generating three-level (or two-level) optimized hierarchical image data in response to raw image data having a three-level hierarchy can readily be generalized to generate N-level optimized hierarchical image data in response to raw image data having M-level hierarchy follows in a recursive manner in accordance with the invention. This is done by working from the terminal cells in a given branch, up to the referring cell (e.g., from the set HI to Cell_A). Note that the same is true for arrays of cells. The benefit of using additional levels of hierarchy is to reduce further the size of the file (to be transferred to the graphics engine) which determines the optimized hierarchical image data. More generally, in a class of embodiments, the invention is a processor (e.g., processor 2 of FIG. 1) that is programmed to generate a set of hierarchical image data having at least two levels of hierarchy in response to a set of hierarchical raw image data, such that the hierarchical image data includes residual data and at least one cell, each said cell determines a feature set of a pattern, the residual data includes at least two subroutine call commands, and each of the subroutine call commands identifies a cell of said at least one cell and a portion of a target at which the feature set determined by the cell is to be imaged, where the processor is programmed with software for: (a) determining a hierarchy graph for the raw image data, identifying said hierarchy graph as a tentative hierarchy graph of a tentative version of the hierarchical image data, and sorting (e.g., determining an indexing structure which sorts) cells of the tentative hierarchy graph according to their individual size relative to total size of the set of raw image data; (b) identifying one of the cells of the tentative hierarchy graph whose size is largest relative to the total size of the tentative version of the hierarchical image data, and if the size of said one of the cells does not exceed a cacheable size, determining whether inclusion of said one of the cells as a cell of the hierarchical image data would cause the size of the residual portion of the hierarchical image data to exceed a predetermined maximum size; (c) if inclusion of said one of the cells as a cell of the hierarchical image data would cause the size of the residual portion of the hierarchical image data to exceed the predetermined maximum size, identifying a new cell that contains multiple instantiations of said one of the cells and has size that does not exceed the cacheable size, updating the tentative hierarchy graph and the tentative version of the hierarchical image data by replacing the multiple instantiations of said one of the cells with said new cell, thereby determining an updated hierarchy graph and an updated version of the hierarchical image data, and if the size of the residual portion of the updated hierarchical image data does not exceed the predetermined maximum size, identifying the updated hierarchical image data as the hierarchical image data. Also within the scope of the invention is a method for generating a set of hierarchical image data having at least two levels of hierarchy in response to a set of hierarchical raw image data, such that the hierarchical image data includes residual data and at least one cell, each said cell determines a feature set of a pattern, the residual data includes at least two subroutine call commands, and each of the subroutine call commands identifies a cell of said at least one cell and a portion of a target at which the feature set determined by the cell is to be imaged, said method including the steps of: (a) determining a hierarchy graph for the raw image data, identifying said hierarchy graph as a tentative hierarchy graph of a tentative version of the hierarchical image data, and sorting (e.g., determining an indexing structure which sorts) cells of the tentative hierarchy graph according to their individual size relative to total size of the set of raw image data; (b) identifying one of the cells of the tentative hierarchy graph whose size is largest relative to the total size of the tentative version of the hierarchical image data, and if the size of said one of the cells does not exceed a cacheable size, determining whether inclusion of said one of the cells as a cell of the hierarchical image data would cause the size of the residual portion of the hierarchical image data to exceed a predetermined maximum size; (c) if inclusion of said one of the cells as a cell of the hierarchical image data would cause the size of the residual portion of the hierarchical image data to exceed the predetermined maximum size, identifying a new cell that contains multiple instantiations of said one of the cells and has size that does not exceed the cacheable size, updating the tentative hierarchy graph and the tentative version of the hierarchical image data by replacing the multiple instantiations of said one of the cells with said new cell, thereby determining an updated hierarchy graph and an updated version of the hierarchical image data, and if the size of the residual portion of the updated hierarchical image data does not exceed the predetermined maximum size, identifying the updated hierarchical image data as the hierarchical image data. Also within the scope of the invention is a method for generating a set of hierarchical image data to be transferred to a graphics engine, in response to a set of hierarchical raw image data, such that the hierarchical image data has at least two levels of hierarchy and includes residual data and at least one cell, each said cell determines a feature set of a pattern, the residual data includes at least two subroutine call commands, and each of the subroutine call commands identifies a cell of said at least one cell and a portion of a target at which the feature set determined by the cell is to be imaged, said method including the steps of: determining a hierarchy graph for the raw image data, and determining a tentative version of the hierarchical image data having said hierarchy graph; and modifying the tentative version of the hierarchical image data to determine an optimized version of the hierarchical image data which achieves an optimal combination of reduced data volume relative to the data volume of the raw image data, and reduced time required for generation of beam control data from the optimized hierarchical image data in the graphics engine relative to the time required for generation of the beam control data from the raw image data in the graphics engine. For example, in a class of implementations of the FIG. 1 system, processor 2 is programmed with software for generating optimized hierarchical image data in response to hierarchical raw image data by assigning a figure of merit to each candidate cell, and using the assigned figures of merit to determine the cells of the optimized hierarchical image data. The figure of merit (xe2x80x9cFOMxe2x80x9d) indicates, in some sense, how much benefit would be derived from caching the candidate cell and retrieving it at least twice (each time in response to a subroutine call command). The FOMs are sorted in decreasing (or increasing) order of FOM, and only those cells whose FOM exceeds a minimum value (or is less than a maximum value) are eligible for inclusion as cells (to be cached) of the optimized hierarchical image data. Those cells whose FOM exceeds the minimum value (or is less then the maximum value) and which satisfy any other criterion or criteria imposed by the programmer, are actually included as cells to be cached of the optimized hierarchical image data. Each cell whose FOM does not exceed the minimum value (or exceeds the maximum value), or which does not satisfy one of the other criteria (if any) imposed by the programmer, is replaced by flat image data which is included in the residual (noncached) portion of the optimized hierarchical image data. For example, the FOM can be the ratio Savings/Size, where: xe2x80x9cSavingsxe2x80x9d is the number of bytes by which the overall image data file (to be transferred to the GE) is reduced by including the cell (as a cell to be cached), along with non-cached subroutine call commands for calling the cached cell, in the optimized hierarchical image data; and xe2x80x9cSizexe2x80x9d is the number of bytes that the cell would occupy in the GE memory (if the cell were cached therein). Alternatively, the FOM can be the above-defined xe2x80x9cSavingsxe2x80x9d value alone (rather than the xe2x80x9cSavings/Sizexe2x80x9d ratio as in the previous example). It is conventional to program a processor (such as processor 2 of FIG. 1) with software causing it to perform a variety of operations on the raw image data it receives before it transfers the processed image data to a graphics engine. Examples of such operations are fracturing and tiling of the raw image data, and converting geometry types of the raw image data into another format such as the Alta Binary Format (ABF) employed in pattern generation equipment marketed by Etec System, Inc. In some embodiments of the present invention, the software which programs processor 2 is a modified version of such conventional software which performs the functions of the conventional software as well as the functions required to implement the invention. It should be understood that the GE memory in which cells of hierarchical image data are cached in accordance with the invention can be a special-purpose cache memory of the GE (used only for the purpose of caching such cells) or it can be a portion of a multi-purpose memory of the GE (which multi-purpose memory is also used by the GE for at least one purpose other than caching of such cells). It should also be understood that while certain forms of the present invention have been illustrated and described herein, the invention is not to be limited to the specific embodiments described and shown or the specific methods described.
	description	1. Field of the Invention This invention relates to the load testing of web applications, and more specifically to the load testing of web applications using random parameter generation. 2. Description of Related Art Communication of data over the Internet, or over other wide area or local area networks, to entities referred to as clients, is accomplished by a web application interconnected via a communication system to the clients. The specific resource requirements upon the web application for processing a client's request for data depend upon the nature of the data. The total load on the web application increases with the number of clients accessing the web application and, with a large number of clients, may exceed the operation capacity of the web application in terms of meeting performance goals. Such performance may be measured in transactions per second (TPS), and average response time, which are examples of client oriented performance parameters, and number of clients being served, and CPU utilization, which are examples of server oriented performance parameters. A load test generally involves simulating the actions of relatively larger numbers of users to determine how the application or transactional server will perform under heavy loads. During the development and testing of a web-based application, the application may be loaded to assess its performance. To conduct such an assessment of a web application, systems known as load generators have been developed to simulate the load generated by clients upon the web application. Load generators may also be used to generate load to put an application under stress while troubleshooting an identified problem with the application, and for other reasons. Often load tests need to be run during the development of a web-based application, and often to test only a portion of the application. Many prior load testing scenarios utilize user logs to generate test scripts for the loading of applications. A significant drawback of methods utilizing user logs or other tracking of past use of a web-based application is that no such logs are available for a yet unused application. Another drawback of such methods is that the tester may choose to significantly load a portion of an application for a particular reason, including troubleshooting, in a way not reflected in any user logs even if the user logs for the application do exist. A computer-based method for load testing a web application. The lightweight computer-based method allows for selection and load testing of URLs accessed by web browsers running on the system. The computer-based method comprises selecting one or more uniform resource locator (URL) parameters, identifying the selected parameters by parameter type, and loading the web application with URLs created by randomly generating the selected URL parameters. An electronic system adapted to load test a web application utilizing URL selection and random parameter generation in a lightweight fashion and without the need of or use of scripts. FIG. 1 illustrates the primary components of a load testing system 100 which provides various functions and services for the load testing of target systems. For purposes of illustration, the load testing system 100 will be described primarily in the context of the testing of websites and web-based applications. In some embodiments, a load testing application resides in the memory of the host computer 101. In some embodiments, a load testing application resides in a computer readable medium accessed and read by the host computer 101. In some embodiments, the host computer 101 is a personal computer. The host computer 101 is communicatively linked to a first electronic platform 104 via a communication link 102. In some embodiments, the communication link 102 is a local area network. In some embodiments, the communication link includes transmission across a global-area communication network 103, such as the internet. In some embodiments, a web-based application resides upon the first electronic platform 104. In some embodiments, the electronic platform 104 is a server. In some embodiments, the web-based application resides upon a plurality of electronic platforms. The load testing application is a lightweight application for the load testing of web-based applications allowing for selection of URLs from URLs accessed by one or more web browsers running on the host computer without the use of scripts. In some embodiments, the load testing application allows for the selection of URL parameters and other items whose values can be modified for the creation of templates used in the load testing of a web-based application. The load testing application allows for the sequential creation and sending of URLs to a web-based application without the use of scripts. In some embodiments, the functionalities of the load testing application will be implemented using a host computer. In some embodiments, the load testing application is operated by the tester using a host computer using a number of graphical user interfaces or dialog boxes that allow for the selection and implementation of the functionalities of the load testing application. Conceptually, the load testing application can be separated into user-interface, or setup, portion, and a run-time portion. The setup portion of the load testing application involves identification and selection of URLs to be used during load testing, and the identification of URL parameters within these URLs which can be varied and used to load a web-based application. The setup portion also involves the selection of configuration parameters for the tests run by the load testing application. The run-time portion of the load testing application generates test URLs that are used to load a web-based application, and then is able to load a web-based application in real time using these test URLs. The run-time portion also stores data from the load testing that can be accessed later for review. FIGS. 2A-B illustrate the opening screen WebTest dialog box 200 of the load testing application according to one embodiment of the present invention. The URL Tests box 207 allows for the creation of and display of templates used in the running of a load test. The tests box 206 displays the list of selected templates to be run in the load test. One or more templates may run during a load test. To create a new template, the New button 201 is pushed. To remove a template from the list, the Remove button 202 is pushed. To modify a template, the Modify button 203 is pushed. To move a template to lower position in the list, which then alters the sequence of URL generation, the Move Down button 204 is pushed. Once one or more templates has been selected, modified, or created, the load test configuration may be saved using the Save 216 or Save As 217 buttons. To load an existing load test configuration, previously saved load test configurations may be accessed using the Open button 218. When creating a new load test configuration from scratch, the New button 215 is pushed to create the first template. When a particular template 205 is highlighted in the tests box 206, the URL template for the highlighted template is displayed in the URL box 208. In some embodiments when running a load test with a number of templates running, the first template listed will generate the first URL which is then sent to the web-based application under load, then the second template will generate the second URL, and so forth, until the last template in the list has generated a URL and sent it to the web-based application. The process will then repeat itself. If one template is configured to be run a fewer number of cycles than the others, this template will have run its course and will be removed from this cyclical process. The load test is a lightweight test that does not require the generation of scripts, or the compilation of any code. The Output box 209 displays and allows for selection of the log file 210 wherein the test data for the load test will be saved. The Browse button 212 allows the tester to browse a file directory from which to select a log file. The View Log button 213 allows the tester to view the log file from a load test. In some embodiments, the log file 210 will keep a record of the actual URL sent at each step of the load test, the http status code returned, and the length of time until the return. In some cases a time out will occur for a particular URL generation before the return of data. To start a test after all the configurations and parameters have been sent, the Start Test button 211 is pushed. To stop a test that is in progress, the Stop Test button 219 is pushed. To close the load testing application, the Close button 220 is pushed. FIGS. 3A-B is a screen shot of the template generation dialog screen 300. When the New button 201 or the Modify button 202 on the opening screen 200 is pushed, the template generation screen 300 is then displayed. The template generation screen 300 allows for the creation of templates which are used in the load testing of a web-based application. The Title box 301 displays the name 302 of the URL template that is being created or modified. The Test box 303 displays the URL template that is being modified or that has been created in the Url box 304. If the tester knows exactly what the tester wants entered for a URL template, it can be directly entered into the Url box 304. In some embodiments, the URL template is a URL selected from a list of instances accessed by a web browser running on the host computer. In some embodiments, the URL or URLs selected are modified into a template which implements a functionality that varies the URL sent to load the web-based-application. In some embodiments, some or all of the URL parameter values are varied. In some embodiments, the values of the parameters to be varied are randomly generated. In some embodiments, the random generation of a particular parameter value proceeds according to rules set by the user to guide the random generation. The Get button 310 implements a functionality that will access web browsers that are open on the host computer. This functionality enables the user to easily select a URL after calling up the corresponding page on a web browser, such as Internet Explorer. The tester is able to select the URL from the running instances of the web browser. A list of web page instances will be displayed in the Browse for URL dialog box 400, as seen in FIG. 4. The top-level Shell instances 406, 408 may be designated with an icon 401, 403. The web pages displayed in a particular instance 407 may be designated with another icon 402. The particular instance to be selected is highlighted and then selected by pushing the OK button 404. The process to build the list of top-level and particular instances may be comprised of the following steps, using the web browser as Internet Explorer (IE) in this example. Because of framing and other methods, an IE window may contain multiple web pages. The load testing application connects to the Windows Shell interface. A list of running Shell instances is made. For each Shell instance, a determination is made to see if the Shell instance is an Internet Explorer instance. This is done by checking to see if the Shell instance supports the IWebBrowser2 COM interface. If the COM interface is supported, the load testing application connects to that COM interface. After connection to the COM interface, the title and top level URL is determined for that Shell instance. The IE instance is added to a list of instances. The exposed DOM interface of the Shell instance is then connected to. Using the DOM interface, it is determined if any frames are displayed. For any Shell instance that has frames displayed, the URL and the title of a frame is determined. This frame is then added to a list of frames for the top level instance. These steps are repeated for each frame within the Shell instance. After all of the frames within the Shell instance are added to the list, the next Shell instance goes through the same process. After all of the Shell instances and frames have been reviewed, all of the COM interfaces are released. The resulting lists are then displayed in the Browse for URL dialog box 400. The selection of URLs to be tested can be done quickly by a tester who browses the pages of a web application that they wish to test. After selection of a URL from the Browse for URL dialog box 400, which is done by highlighting the URL to be selected and pushing the OK button 404, the tester is returned to the URL Test dialog box 300. To implement the functionality which will generate random values for some or all URL parameter values or parameter names, the Build Parameter Randomizations button 305 is pushed. The load testing application then displays the Edit URL Parameters dialog box 450, as seen in FIGS. 5A-B. The name-value pairs for the selected URL are displayed, with the names 453, 461 in the Name column 451, and their associated values 454, 462 in the value column 452. With the selection of a name or a value, and the pushing of the Suggest button 455, a suggestion is made on how to vary the name or the parameter value. In some embodiments, the name or parameter is evaluated by the load testing application; for example, a four digit number value may be evaluated and the load testing application may suggest that a number from 0000-9999 be randomly generated and substituted in for this parameter value for each iteration of the load testing of the web-based application that uses the template based upon the URL which contains the parameter. A new parameter may be added by pushing the Add button 457. A parameter may be deleted using the Delete button 458. If the user is not satisfied with the parameter randomization that has been generated, the tester may push the Cancel button 460 and the operation will not be used. In a case where the tester was modifying an earlier set or parameter value randomization choices for a URL, the earlier set will remain in place. This result will also occur if the Restore button 456 is pushed. If an earlier set of randomization choices has not been made for the URL, no randomization will have been selected and the URL, if used in a load test, will be sent each time with the same values as the original URL. If the tester is satisfied with the parameter value randomization that has been generated, the tester may toggle the OK button 459. In either case, the tester is returned to the URL Test dialog box 300. The Advanced box 306 allows the user to set some template configuration parameters for the selected template 302. The Limit Runs box 307, when selected, allows the tester to set a number 308 of runs that the particular template will cycle. If the Limit Runs box 307 is not selected, the template will not be limited by number of cycles. The Sleep Time box 309 allows for the setting of the number of milliseconds that the test can pause before iterating again. In some test run cases, the tester may want to have a pause before an action repeats, simulating that a tester has waited between certain actions. This functionality may also be used if the server requires a wait time to asynchronously store input into a database. The Results File box 319 allows for the selection of an output file that will store the returned content. If no file is placed in the file line 320, no data will be saved using this functionality. The Browse button 322 allows for the selection of a file to be used to store the results. The View button 323 allows the tester to view the stored data from the previous run of the template. The Append box 321, if selected, implements a functionality wherein all content returned for each iteration of the test will be saved in the results file. If the Append box 321 is not selected, each content object returned on each cycle overrides the saved data from the previous cycle. The tester may access the Edit Tags dialog box 500, as seen in FIGS. 6A-B, from the WebTest dialog box 200 by pushing the Tags button 214. The tags functionality allows the tester to insert a tagged value into a URL so that a particular portion of the URL can be varied, while maintaining all of the other aspects of the template, such as configuration parameters, parameter randomization selections, and so on. The tags are displayed in a Name column 501 and a Value column 502, which contain the names 507-510 which are paired with their values 511-514. The Add button 503 and the Delete button 504 allow for the addition and the deletion of tag name-value pairs. When the preferred tag name-value pair has been highlighted, the OK button 505 will select that tag and return the tester to the WebTest dialog box 200. The Cancel button 506 cancels the tag selection process and the URL template will not be altered. The addition of tags allows for substitution of any particular portion of the URL during the running of a template. A tagged value will be the same for each iteration of the URL during the load test when that particular template is loaded. In contrast to parameter values which may be varied for each test URL generated, the tag value does not change during the course of the load test. In some embodiments of the present invention, a template is created to implement the functionality of randomly varying the value of one or more URL parameters, as seen in FIG. 7. The method of creating the template may be implemented using a computer based electronic system. The method may be implemented by a load testing application residing in a host computer in some embodiments. The method may be part of a load testing application residing upon a computer readable medium in some embodiments. The template may be used in the loading of a web-based application during a load test. In order to create a template according to this embodiment, the tester selects a starting Uniform Resource Locator (URL) 10. The URL selected typically consists of the following components: the protocol, the server, the port (often omitted), the directory, the application, and the URL parameters. The URL components are also summarized as protocol://machine address/path/filename. In the case of dynamic web pages, the URL parameters are selected prior to requesting the URL content object. Common use of web-based applications involves entering URL parameters as part of the use of or navigation through a web-based application. Although many web-based applications utilize Hypertext Transfer Protocol (HTTP), the present invention may be used with any of a variety of protocols. When displaying only the portion of the URL involving the web application and, for example, two parameters, the syntax may be as follows: [URL webapp]?[parameter 1]&[parameter 2] The selection 10 of the starting URL for a template is followed by review of the starting URL for identification of parameters to be varied 11. This review for identification of parameters to be varied is done by the tester in some embodiments. The review for identification of parameters to be varied is done automatically by the load testing application in some embodiments. The URL may have one or more parameters with variable values. In some embodiments, all of the parameters whose values are to be varied are identified at one time. After the identification of the parameters whose values are to be varied, one of the identified parameters is selected 12. The selected parameter is then assessed as to parameter value type 13. The assessment of a parameter for parameter value type is done by the tester in some embodiments. The assessment of a parameter for parameter value type is done automatically by the computer system in some embodiments, or in part by the tester and in part by the computer system. For example, the parameter value type may be text, a combination of text and numeric characters, numbers, binary data, symbolic characters, a sequence, or may be chosen to be more than one of the afore-mentioned types, or may be of another type, and may be of a certain quantity of characters. After identifying the parameter value type, particular ranges for the parameter values may also be set. For example, a numeric parameter value could be assigned a four digit value between 1000 and 5000. Also, a particular parameter value could be broken into sub-parts, with each sub-part assigned a parameter value type and a value range. After assessment of the parameter value type of the first selected parameter, a review 14 is made to check if all of the selected parameters have had their values assessed as to type. The process is repeated 15 if any remaining selected parameters have not been assessed as to parameter value type. This is repeated until all selected parameters are assessed as to parameter value type 16. In some embodiments, a parameter value is selected to be varied, and then assessed as to type before selecting another parameter. In some embodiments, all of the parameter values to be varied are selected, and then the selected parameters values are assessed as to type. A parameter template can be used to create URLs that are made up of any combination of static values and dynamic (random) values. One advantage of this method is that the tester can set up templates that send purposefully invalid URLs. This will allow for testing, for example, of how the application responds to such invalid requests. The template configuration parameters are then set 17 in some embodiments of the present invention. The configuration parameters may use default values in some embodiments. The configuration parameters may include items such as the maximum allowed wait time for a response before proceeding to the generation of the next URL, the number of cycles to run the template, the amount of time to run the template, and other values. Once the template configuration values are set, the template creation process is complete 18. In some embodiments of the present invention, the following syntax is used for inserting the random values for the selected parameter values: Parameter-Template = “(“ contents “)”Contents = free-text \| random-valueRandom-value = token token-parameterToken = s-token \| or-tokens-token = “text” \| “textnum” \| “num” \| “bin” \| “symbol” \| ”seq”or-token = “or” parameter-template parameter templateToken-parameter = value \| rangeValue = digit { digit }Range = value “–“ valueFree-text = { free-text-character }Free-text-character = any-character-except-right-parentheses The representative syntax seen above is used as an example of generating random values for a data item that is to be varied. In some templates, a plurality of parameters or parameter values of similar or different type are generated. The template creation as described above allows a tester to load test an application without the need to create any scripts. Also, no additional programming is necessary. In addition, this template can be developed without the need to scan application code. In the syntax seen above, the syntax for varying a URL parameter includes a symbolic character opening the varying part of the parameter from the static part of the parameter. Then a command specifies how to vary the part selected to be varied. A plurality of arguments for this command are then included. A symbolic character then closes the varying part of the parameter. In the syntax defined above, the symbolic character opening the varying part may be a left parentheses, and the symbolic character closing the varying part may be a right parentheses. In some embodiments of the present invention, as seen in FIG. 8, a template is utilized to load a web-based application. The web-based application is or is part of a distributed internet application such as a web server, a cgi program, an application server configuration, a J2EE application, an ASP/COM based application, or any other type of application that serves users over the internet or other network. Beginning with a created template 40, the values of one of the selected parameters is varied 41 using the rules chosen during the creation of the template. The parameter values are varied using standard randomization algorithms according to the parameter type. If values of all of the selected parameters have not yet been varied 42, this step is repeated until all selected parameters have had their values varied 43. A new URL is created using the varied parameter values 44. The new URL is submitted to the web-based application 45. In some embodiments, the submission is done over a global-area computer network, such as the internet. In some embodiments, the submission is done over a local or wide area computer network. In some embodiments, a template varies the values of the same parameters for the same starting URL repeatedly. In some embodiments, a load test runs a series of templates with different starting URL's and their varied parameter values and then repeats that series. In some embodiments, the different templates are set to run for different number of cycles, so one of the templates may finish its number of cycles before the end of the load test. The load test will then proceed running with the other templates until their completion. After submission of the URL to the application, the process waits for a specific event 46, which can be a response from the application, a specified duration of time, or other event. In some embodiments, the specific event is the return of the content object requested. In some cases, the submitted URL will not return data from the server data store, and the returned content object will be a statement to that effect. In either case, the web-based application has been loaded by the load testing application. In some embodiments, the operation will time out after the elapsing of a pre-determined amount of time. In this case, the load test will proceed to the next step after this time period has elapsed. After the specified event occurs, and if the configured number, or time duration, of submissions has not been run 47, the process repeats itself 48. During the next cycle, the URL parameter values are again varied, a new test URL with the varied parameter values is created, and this new test URL is submitted to the web application. If the configured number, or time duration, of submissions has been run 49, the running of the load test is complete 50. In some embodiments of the present invention, as seen in FIG. 9, the load testing of a web application is illustrated. The templates are created 60 according to the afore-mentioned method in some embodiments. The operator determines 61 if enough templates have been created. If enough templates have not been created 62, more templates will be created 60. If enough templates have been created 63, the operator selects the quantity of each template to run 64. In some embodiments, this selection is done automatically using an electronic system. After the selection of the quantity of each template to run, the application is loaded 65. The loading is done by sending the modified URLs to the web-based application over a local connection, over a local area network, over a wide area network, or over global-area computer network such as the Internet. In some embodiments, the amount of time, or number of times, that the application is to be loaded is selectable after the selection of the templates. In some embodiments, the amount of time, or number of times, that the application is to be loaded has been previously selected during the creation of the template. In some embodiments, the load test will be applied to the application while other performance measurements of the application are being made. In some cases, the load applied may not be the level of load desired by the tester. The tester may evaluated whether the load applied is appropriate 66, and if it is not the quantity of each template to be run may be re-visited 67. In some embodiments, the load test is run from a plurality of host computers. In some embodiments, the plurality of host computers may be simultaneously loading one or more web-based applications. In some embodiments, the quantity of each template to run may be adjusted without stopping the load test. In some embodiments, the load test may have to be stopped to modify the template quantities. If the load applied is appropriate 68, the application continues to be loaded 69. After the load test has run the pre-set time or the pre-determined number of cycles, the load test ends 70. In some embodiments of the present invention, the computer-based method as described above is stored on a computer readable medium comprising instructions to implement some or all of the functionalities. The computer readable medium, when executed by a computer, causes the computer to perform the method as described. FIG. 10 illustrates a load test 80 according to some embodiments of the present invention. The load test is started 81, and this begins the running of the selected templates. In this example, template 1 is run 82, another template 1 is run in parallel 83, one of template 2 is run 84, and one of template 3 is run 85. Each template is run until its conclusion 86, 87, 88, 89. After the conclusion of the running of all of the templates, the load test is complete 90. In some embodiments, each of the templates run in parallel are run for the same amount of time. In some embodiments, each of the templates is run for a pre-set number of cycles or a pre-set amount of time that is separately set for each template. FIG. 11 illustrates a load test 350 according to some embodiments of the present invention. In this illustrative example, three templates are included as part of the load test. The load test is started 351, and the first template is checked 352 against the number of cycles set as its run limit. In some cases, no limit will be set on the number of cycles. In some cases, a limit will have been set for the number of cycles to run each of the templates. In some cases, the limits set for each of the templates will be different from one another. If the cycle limit for template 1 has not been reached, a test URL based on template 1 is created and sent 353. In some embodiments, a specified event is then waited for 354. This may be a return of data, the passage of a specified amount of time, or some other event. If the cycle limit for template 1 has been reached, use of template 1 is not made. Next, template 2 is evaluated as to the number of cycles it has run 355. If the cycle limit for template 2 has not been reached, a test URL based on template 2 is created and sent 356. In some embodiments, a specified event is then waited for 357. If the cycle limit for template 2 has been reached, use of template 2 is not made. Next, template 3 is evaluated as to the number of cycles it has run 358. If the cycle limit for template 3 has not been reached, a test URL based on template 3 is created and sent 359. In some embodiments, a specified event is then waited for 360. If the cycle limit for template 3 has been reached, use of template 3 is not made. This process repeats itself until the cycle limit for all of templates is reached 361 and then the test is at an end 362. The foregoing description assumes a set of URL parameters to be submitted through a URL. In http-terms, this is known as the GET method. The mechanism can easily be used with the POST method. Using POST, the data submitted may or may not have URL parameters, in the same format as GET does, that is, using name-value pairs. Whether the posted data contains name-value pairs or not, the same approach can be used to vary any part of the URL or data. The same is true when using the PUT http method. Any TCP data, UDP data, or data submitted to a server using any other protocols can be varied using this mechanism. As evident from the above description, a wide variety of embodiments may be configured from the description given herein and additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is, therefore, not limited to the specific details and illustrative examples shown and described. Accordingly, departures from such details may be made without departing from the spirit or scope of the applicant's general invention.
	abstract	An assembly for Kratky collimator is provided. The assembly may be used for a small angle x-ray camera or system requiring such filtering. The assembly may include a first block with a first working surface and a second block with a second working surface. The first and second blocks may be aligned with the first working surface pointing an opposite direction of the second working surface and the first working surface being aligned in a common plane with the second working surface. In some implementations, the first block may comprise a crystal material. In some implementations, an extension may of the first block may be configured position a beamstop.
	description	This application is a continuation of U.S. Nonprovisional patent application Ser. No. 14/773,405 filed Sep. 8, 2015, which is a U.S. National Stage Patent Application under 35 U.S.C. § 371 of International Application No. PCT/US2014/034102, filed Apr. 15, 2014, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/816,060, filed Apr. 25, 2013. The subject matter of these earlier filed patent applications is hereby incorporated by reference in its entirety. The United States government has rights in this invention pursuant to Contract No. 89233218CNA000001 between the United States Department of Energy and Triad National Security, LLC for the operation of Los Alamos National Laboratory. The present invention generally relates to power systems, and more particularly, to a mobile heat pipe cooled fast reactor system. Conventionally, diesel or gas-powered generator systems may be used to provide electricity to locations that do not have access to a reliable electrical grid, or where an electrical grid is unavailable. However, a significant issue with these systems is that fuel must be transported to the location to supply the generator. This may require significant transportation resources and come at significant cost. Nuclear reactors may be particularly useful for applications where power is needed for systems that are logistically remote from conventional fuel sources, such as systems deployed in the Arctic, a forward military base, or other geographically remote areas. However, conventional nuclear reactors tend to be large and require circulating coolant fluids. Accordingly, an improved reactor suited for deployment in remote environments may be beneficial. Certain embodiments of the present invention may provide solutions to the problems and needs in the art that have not yet been fully identified, appreciated, or solved by conventional reactor technologies. For example, some embodiments of the present invention pertain to heat pipe cooled reactor systems that are nearly solid state and have only a small amount of fluid. The reactor systems of some embodiments may be modular and configured to be transported in standard intermodal shipping containers, for example. Heat pipe reactors using alkali metal heat pipes, for example, may be particularly well suited for mobile/remote applications because they tend to be inherently simpler, smaller, and more reliable than “traditional” reactors that rely on pumping coolant through the reactor core. In an embodiment, a system includes a plurality of heat pipes including coolant and a plurality of fuel pins containing nuclear fuel. The plurality of fuel pins are positioned proximate to the plurality of heat pipes. The heat pipes extend outward from a reactor core through a block and are configured to transfer heat away from the reactor core. In another embodiment, a system includes a mobile heat pipe cooled fast reactor and a cask housing the mobile heat pipe cooled fast reactor. The system also includes a skid including rollers or tires and a cradle operably attached to the skid. The cradle is configured to secure the cask in place to transport the mobile heat pipe cooled fast reactor using the skid. In yet another embodiment, an apparatus includes a containment vessel surrounded by a neutron shield. The neutron shield is surrounded by an air gap. The apparatus also includes a gamma shield that defines an outer boundary of the air gap. The air gap provides cooling for the gamma shield. The apparatus further includes an outer wall that covers the gamma shield. Some embodiments of the present invention pertain to a heat pipe cooled reactor power system that may be nearly solid state and have no circulating fluid. There are no pumps or valves in the vessel/core area like in a water or liquid metal cooled reactor. Also, other than control drums, moving parts could be limited to the power conversion system. Furthermore, high temperatures can be achieved, emergency decay heat removal can be made passive, and heat pipe reactors can generally work in any orientation. Heat pipe reactor systems in some embodiments may provide long term power in desired environments for five years or more. Heat pipe reactors may have many advantages over conventional reactors. Their nearly solid state design and lack of circulating coolant fluid can significantly enhance safety and reliability of the reactor. Corrosion is less of an issue, and there is only a small amount of fluid that could spill, limited to the amount in the heat pipe. There are no positive void coefficients, which improves the nuclear safety case, and there is no high pressure (compared to a gas cooled reactor). Also, heat pipes increase the surface area for heat extraction and allow for multiple heat extraction systems. Some embodiments use either a carbon dioxide (CO2) Brayton cycle power conversion system (air cooled) or a direct air Brayton cycle power conversion system. Heat pipe reactors using alkali metal heat pipes, for example, are perfectly suited for mobile applications because their nature is inherently simpler, smaller, and more reliable than “traditional” reactors that rely on pumped coolant through the reactor core. Instead of the single point failure of a pumped loop reactor system, hundreds of heat pipes passively remove heat, including decay heat, from the core using relatively simple and well-characterized physics. The heat pipes remove heat as liquid in the heat pipe is vaporized. These reliability and safety advantages are especially important for remote sites. The robust, solid-state characteristics of the core are also advantageous for potentially damaging transport conditions or perhaps hostile operating environments. The use of heat pipes instead of liquid or gas coolants may lead to a lightweight and small design as compared to conventional reactors. For mobile reactor designs, these are generally desirable attributes. In addition, heat pipe reactors may operate at high temperature, which may allow for a smaller power conversion system. This is also generally desirable for a mobile reactor. In some embodiments, the reactor and the power conversion system may fit into a standard intermodal shipping container that is 8 ft.×8 ft.×20 ft., for example. Some embodiments of the heat pipe cooled reactor may provide a safe and reliable power source of approximately 1 to 2 megawatts (“MW”) of electric power and/or provide clean water via waste heat or reverse osmosis, although some embodiments are capable of achieving 5 MW thermal or more, and any desired power output may be achieved as a matter of design choice. The heat rejection system may fit into a separate container, and another container may be used for a control room. This may allow for rapid deployment of the reactor by government agencies, the military, or other entities to areas where logistics are a concern, such as disaster areas, remote locations, remote military sites, and in spacecraft. The opportunity cost of not having to ship fuel to the location may be a significant driver for the use of such reactor technology. This may also free up more cargo space for logistical purposes since shipping fuel means not shipping other cargo, such as food, medicine, military equipment, etc. For military applications in particular, sustainable energy at forward locations is generally a vital need. It typically takes approximately 7 gallons of fuel to supply one gallon to a fossil fuel generator. Furthermore, the majority of improvised explosive device (“IED”) fatalities have occurred while protecting fuel convoys. In some embodiments, a heat pipe reactor system may produce approximately 2 MW and weigh approximately 35 metric tons. Such embodiments may be transportable by air (e.g., by C-17 aircraft) and highway (e.g., by truck), allowing deployment to forward battlefield locations or other remote locations. These embodiments may enable savings of 92.5% of the fuel used at forward military bases, for example. An equivalent 2 MW fossil fuel generator would consume approximately 1.2 million gallons of JP8 fuel per year. An equivalent photovoltaic (PV) system and battery would weigh approximately 1,236 metric tons. Such deployable embodiments may be configured to be “wheeled into” and “wheeled out of” a forward location. In certain embodiments, the entire system can be connected to generators and fully operable within 72 hours of arrival. Furthermore, such embodiments may be shut down, cooled, disconnected, and wheeled out in less than a week. The reactor is shut down by either turning control drums at the reactor core edge or by inserting a central control rod. The reactor core and other critical equipment may be housed in special armor, such as boron carbide, lead, and/or steel, for example. This armor may protect the reactor system from attacks, as well as shield personnel and equipment from core radiation during operation and transport. FIG. 1 illustrates a heat pipe 100, according to an embodiment of the present invention. Heat pipes are passive heat removal devices that efficiently move thermal energy. Heat pipes are sealed tubes (i.e., container 102) that contain a small amount of a volatile liquid 104 (e.g., liquid potassium or sodium). The liquid 104 is boiled at one end of the tube (i.e., evaporator 106) via heating coil 108 and the vapor 110 travels to the other end of the tube (i.e., condenser 112) where it condenses (i.e., condensate 116), depositing its heat of vaporization with a small attendant temperature change. The condensed liquid is then returned to the other end of the tube by means of a wick 114 using capillary forces, drawing the condensate 116 back toward the heated zone. The shape of heat pipe wick 114 imposes order on a saturated liquid by: (1) forming menisci 118 between the condensate 116 and the vapor 110; and (2) allowing the condensate 116 to flow toward the heated zone. As such, a heat pipe, being isothermal, moves the working fluid for power conversion away from, and outside of, the core. Heat pipes also may extend the surface area available for heat transfer. In conventional reactors, a single reactor coolant is typically the only mechanism for extracting heat from the reactor core. Safety is achieved by attempting to prevent the set of failures that could lose the fluid, cause the fluid not to circulate, or cause the fluid to lose its heat transfer capabilities (e.g., transition from nucleate to film boiling). Redundant equipment (pumps, electrical systems, etc.) or passive components are usually used to attempt to prevent failure. However, in heat pipe reactors of some embodiments of the present invention, an array of heat pipes is used to remove heat from the reactor core using reliable and well-characterized physics (i.e., capillary action, boiling, and condensation). Typically, unless common cause failures dominate, the failure of multiple heat pipes will be much lower than the failure rate associated with a conventional coolant system. Thus, traditional measures of safety could be an order of magnitude better in some embodiments. In certain embodiments, the mobile heat pipe cooled fast reactor only consumes 5 g of U235 per day (100 MW hours). The reactor also produces 1.7 g of Pu239 per day (100 MW hours). After two years of operation, the Pu inventory would be approximately 1.2 kg and the concentration would be ˜0.01% (commercial spent fuel is ˜1%). Extreme core radiation generally prevents access to the fuel. In some embodiments, the only moving parts are control rods and power conversion. This makes such embodiments close to solid state. The feed mechanism for normal and emergency cooling could also be gravity fed. Assuming that there are no structural issues, this could improve reliability. It could also reduce maintenance costs and increase the ease of operation. FIG. 2 illustrates a power system 200 with closed loop CO2 Brayton cycle power conversion, according to an embodiment of the present invention. Power system 200 generally requires a heat rejection system, but tends to be more efficient than open air Brayton cycle systems. The pressure used in such systems may be moderate (e.g., 200 psi). Reactor 210 may have a solid core of stainless steel. While shown as a simulator here for testing purposes, in practical implementations, a real reactor would be used. Uranium dioxide (UO2) or UN fuel, or any other suitable fissile material, may be used as a fuel source in holes in the core surrounded by an inert gas such as helium. In some embodiments, the nuclear fuel material may be hundreds of times less hazardous than material that is regularly shipped around the globe every day, such as highly toxic MOX spent fuel. Heat pipes 222 extend through reactor 210 and heat exchangers 220, and may include any suitable coolant material, such as sodium or potassium. Heat pipes 222 may connect to several heat exchangers. One heat exchanger may be used for heating a working fluid (gas) and one or two other heat exchangers may be used for decay heat removal. A typical Brayton power conversion system compresses the working fluid (such as CO2) using compressor 230, then passes it through the heat exchanger before releasing the gas through a turbine 232 to do work (e.g., to make electricity via generator 240) and then passing the working fluid through a heat rejection system 250 to complete the thermodynamic cycle. FIG. 3 illustrates a power system 300 with air Brayton cycle power conversion, according to an embodiment of the present invention. Power system 300 generally does not require a heat rejection system, but tends to be less efficient than a closed loop CO2 Brayton cycle system. In an open air Brayton cycle, air is the working fluid and it is released into the environment instead of be cooled and recycled through the system as in a closed loop CO2 Brayton cycle. FIG. 4 illustrates an assembled core block with heat pipes 400, according to an embodiment of the present invention. Assembled core block with heat pipes 400 includes upper heat pipe tubes 410 that are welded to block 420 via weld joint 430. The block holds the heat pipes and fuel pins in place and allows for heat to be transferred between the heat pipes and fuel pins. Fuel 440 is positioned between the heat pipe tubes below block 420. This allows the heat pipe tubes to transfer heat derived from the fuel for external use. FIG. 5 illustrates reactor elevations 500 for heat pipes and fuel in the reactor core, according to an embodiment of the present invention. The elevations are given taking into account the lengths of the core reflector in the fuel pin, the fuel in the fuel pin, the fission gas plenum in the fuel pin, the shielding outside the core, the location of the lower heat exchanger for decay heat removal, and the location of the upper heat exchanger for the power conversion working fluid. A lower reflector 510 and an upper reflector 530 are located below and above an active core 520, respectively. A fission gas plenum 540 is located above upper reflector 530. A shield 550 is located above fission gas plenum 540, and a decay heat exchanger 560 is located above shield 550. An active heat exchanger lower plenum 570 and upper plenum 590 are located below and above an active heat exchanger 580, respectively. All references to “above” and “below” are in respect to the orientation shown in FIG. 5. Axes A and B, which are also shown in FIG. 10, are shown in FIG. 5 for the purpose of depicting orientation with respect to the heat pipes and fuel pins. Axis A runs parallel to the heat pipes and fuel pins of the reactor length-wise (i.e., in a direction running through the center of the heat pipes and fuel pins, but perpendicular to the circumference thereof), and axis B is defined as perpendicular to axis A (i.e., parallel to the circumference thereof). FIG. 6A is a cross-sectional view of a smaller version of the mobile heat pipe cooled fast reactor 600, according to an embodiment of the present invention. Reactor 600 includes a core block 610 that houses heat pipes 620 and fuel pins 630. A reflector 640 surrounds core block 610 and scatters neutrons and gamma radiation that escapes from the core. Rotating core control drums 650 and B4C crescents 660 are used to provide reactivity control for the reactor. In some embodiments, all of control drums 650 may be moved individually to near-equal positions (i.e., all drums are at the same or a similar angle). Even if several of control drums 650 do not rotate to their respective positions, the core will still be subcritical in many embodiments. FIG. 6B is a perspective cutaway view of a smaller version of the mobile heat pipe cooled fast reactor 600, according to an embodiment of the present invention. Such a reactor may produce 250 kW of power and be suitable for a myriad of applications, including terrestrial and space applications. FIG. 7A is a perspective cutaway view of a mobile heat pipe cooled fast reactor 700, according to an embodiment of the present invention. A heat pipe array 710 includes a plurality of heat pipes 720. Fuel pins 730 are placed adjacent to heat pipes 720 such that heat pipes 720 can transfer heat from fuel pins 730. An axial reflector 740 scatters neutron and gamma radiation. A fission gas plenum 750 is used for containing fission gas release as the core fissions. Such embodiments may use proven UO2 fuel (19% enriched) and may have a steel monolith core (not shown). Passive coupling may be used for heat pipes 720 with no moving parts. Reactor 700 may be housed in an armored and shielded cask (not shown), as shown in more detail below. FIG. 7B is a separated side cutaway view of mobile heat pipe cooled fast reactor 700, according to an embodiment of the present invention. A heat pipe wall 722 surrounds each of heat pipes 720 showing how the heat pipes would be welded to the solid metal block core. Fuel pellets 732 include radioactive material such as UO2 that serves as fissile material for reactor 700. FIG. 7C is a separated side cutaway view of mobile heat pipe cooled fast reactor 700 with perspective views of fuel pellets 732 and a top view of heat pipes 720 and fuel pins 730, according to an embodiment of the present invention. Dime-sized nuclear pellets 732 are stacked in the monolith in this embodiment. The core monolith in this embodiment has openings for fuel pins 730 and heat pipes 720, and may further conduct heat from fuel pins 730 to heat pipes 720. Heat pipes 720 passively transport heat generated in the core to turbine fluid, for example, to facilitate power generation. FIG. 8 illustrates a reactor core arrangement 800, according to an embodiment of the present invention. Heat pipes 810 (shown slightly larger) are located proximate to fuel pins 820. Corner heat pipes 810 are adjacent to one fuel pin 820, side heat pipes 810 are adjacent to three fuel pins 820, and inner heat pipes 820 are surrounded by six fuel pins 820. In this embodiment, there are 2,112 fuel pins 820 and 1,224 heat pipes 810. Each fuel pin 820 has a diameter of 1.425 cm and each heat pipe 810 has a diameter of 1.575 cm. However, any number and arrangement of heat pipes and fuel pins may be used, depending on the application. As can be seen, the core consists of six thermally and mechanically independent segments 830, although any number of segments may be used. The number of heat pipes in a reactor block can be a potential impediment to scaling a heat pipe reactor. Depending on the type of working fluid and the heat pipe design, most heat pipes have a limit on heat throughput per heat pipe. Given this limit, the larger the reactor, the more heat pipes that are typically required. However, there is a limit on the practical number of heat pipes that could be realistically manufactured into a solid block core. Limits on the number of heat pipes can be overcome by breaking the core into smaller segments. A heat pipe reactor can be broken into segments that are mechanically and thermally isolated, but are neutronically connected. An example of this configuration is shown in segments 830 of FIG. 8. By limiting the segments to a size corresponding the perceived level of manufacturability, the reactor core can be scaled to the size needed for various applications. In other words, more segments can be used to generate more power. Some embodiments use a CO2 Brayton cycle power system instead of a Rankin cycle system. Some of the advantages of this configuration are that it tends to be smaller and lighter and more heat is produced (˜600° C. in come embodiments), leading to a higher efficiency system with the potential for process heat applications. Also, there is less heat to reject. CO2 also has favorable properties for a Brayton system. The relatively high molecular weight is better for low power Brayton cycle heat engines. Also, low cp/cv (1.2) leads to low pumping power. Further, better performance than a HeXe mixture at similar molecular weight may be realized. FIG. 9 illustrates comparative turbine sizes 900 for He and supercritical CO2. As can be seen, steam turbine 910 is the largest and produces 250 MW using 55 stages. He turbine 920 produces 333 MW using 17 stages, and the size is reduced to approximately 5 m. Supercritical CO2 turbine 930 is smaller still and produces 450 MW using only 4 stages. FIG. 10 is a side view of a mobile heat pipe cooled fast reactor 1000, according to an embodiment of the present invention. Reactor 1000 includes potassium filled heat pipes 1010 with a steel casing. An Al2O3 reflector 1020 surrounds a monolith core 1030 and reflects neutron and gamma radiation. A primary (i.e., active) heat exchanger 1040 exchanges heat from nuclear reactions to a power conversion cycle and a decay heat exchanger 1050 exchanges heat from decay of the fuel material out of reactor 1000. As in FIG. 5, axes A and B are shown for the purpose of depicting orientation. Axis A runs parallel to heat pipes 1010 length-wise in reactor 1000 (i.e., in a direction running through the center of the heat pipes, but perpendicular to the circumference thereof), and axis B is defined as perpendicular to axis A (i.e., parallel to the circumference thereof). FIG. 11A illustrates a mobile reactor and transportation system 1100, according to an embodiment of the present invention. In this embodiment, a cask 110 containing a mobile reactor is secured to a skid with rollers/tires 1150, but a train car, truck, container, or any other transportation mechanism may be used in other embodiments. Cask 1110 with the mobile reactor inside weighs about 35-45 tons loaded, holds three tons of fuel in five tons of steel monolith, and is approximately 12 feet long with a 6 foot diameter. Cask 1110 is designed to be robust, and the boron carbide shield (see FIG. 11B) also acts as armor. Two impact absorbers 1120 are at either end of cask 1110. Openings 1122 are provided for shield cooling flow and also for airflow through the core in case of an emergency. Impact absorbers 1120 may include a steel shell filled with soft wood, ridged foam, honeycombed material. A cradle 1130 attaches cask 1110 to skid 1150 and a personnel barrier 1140 protects workers from exposure to a high dose of radiation. Personnel barrier 1140 may be stuffed with locally fabricated shielding (ALARA) in some embodiments. FIG. 11B illustrates a side view of cask and reactor 1160 of FIG. 11A, according to an embodiment of the present invention. A ¼ inch thick stainless steel outer wall 1161 contains the reactor. A four inch thick lead gamma shield 1162 deflects gamma radiation. A 1-2 inch air gap 1163 provides shield cooling for lead gamma shield 1162 and six inch thick B4C neutron shield 1164. A 1-2 inch stainless steel containment vessel 1165 separates the inner reactor from the cask. For the mobile embodiment depicted in FIGS. 11A and 11B, a power output of 0.5 to 2 MW may be realized. Power conversion may be accomplished by coupling the reactor to a conventional power conversion system. Heat rejection may be accomplished using air or waste heat may be used for other missions. The reactor may be controlled remotely or locally. Self-regulation may be provided for power output. Embodiments may be reliable and safe, with three independent means of removing decay heat and two independent means of shutdown. The heat pipe cooled core may have no active components, passive heat removal may occur following shutdown, and a large heat capacity may be achieved. FIG. 12 is a perspective view of a truck and trailer 1200 configured to transport a mobile heat pipe cooled fast reactor 1210, according to an embodiment of the present invention. Reactor 1210 is contained within cask 1220, and may generate 0.5-5 MW, depending on the configuration. Cask 1220 may be an armored, shielded, and certified transport cask. In an embodiment, which can be found in corresponding PCT Application No. PCT/US2014/034102, a non-nuclear end-to-end 200 kW prototype was used to test the heat pipe concept. The prototype has a similar heat pipe and fuel pin configuration to that shown in FIG. 7B, for example. The reflectors are Al2O3 in the prototype. A simulated nuclear reactor core used electricity to simulate nuclear power. Complex electronics are used to simulate reactor physics feedback mechanisms during operation of the prototype. The prototype allows the simulation of the reactor to power conversion components without using an actual reactor undergoing fission. A non-nuclear prototype core block was used in a prototype embodiment (see PCT Application No. PCT/US2014/034102). Electric heaters were used to the heat core block to temperatures that were routinely in excess of 1,200 K. The components that were fabricated and tested included heat pipes, heat exchangers, and structural elements. These components were tested for over 4,000 hours to demonstrate proof of concept. FIG. 13 is a virtual schematic of a non-nuclear prototype core block 1300, according to an embodiment of the present invention. A plate 1310 holds heat pipes 1330 in place. Heat pipes 1330 contain a liquid metal such as sodium or potassium. Heat pipes 1330 are heated electrically to simulate nuclear fission. The heat from heat pipes 1330 is then delivered to heat exchangers 1320 in the same fashion that a nuclear heated core block would. FIG. 14 is a schematic of a once-through air Brayton system 1400, according to an embodiment of the present invention. Fuel oil powered Brayton systems are conventionally available, and the system can be used before the nuclear reactor system arrives to provide power. The flow of system 1400 can be realigned upon arrival of mobile heat pipe cooled fast reactor 1410. Reactor 1410 includes heat pipes that are in contact with or sufficiently proximate to a heat pipe heat exchanger 1412 that is heated by reactor 1410 via the heat pipes. Heat is transferred via a working fluid (e.g., air, carbon dioxide, etc.) contained in a series of pipes. In this embodiment, a working fluid is heated via heat exchanger 1412 to approximately 1100 Kelvin (K) at a pressure of one megapascal (MPa), and the working fluid is provided to a turbine 1444 to do work. The working fluid is supplied to the “combustor” of turbine 1444 and powers turbine 1444 in a similar manner to burning fossil fuel. In some embodiments, if reactor 1410 is not present or otherwise is not working, a series of valves (not shown) may be turned in turbine 1444 to enable turbine 1444 to operate by combusting fossil fuel. Turbine 1444 and a high pressure compressor (HPC) 1442 are connected to, and drive, a generator 1440 to produce electricity. After exiting turbine 1444, the pressure and temperature in the working fluid have been reduced to approximately 0.25 MPa and 850 K, respectively. The fluid then drives a turbocharger 1460 that accepts ambient air at approximately 298 K via a silencer 1470. The turbocharger includes an intercooler 1450 and feeds air to HPC 1442. Air provided from intercooler 1450 is at a pressure of approximately 0.4 MPA and the temperature is reduced by approximately 140 K, significantly increasing the density of the air. Air leaving HPC 1442 is at approximately one MPa and 477K, and working fluid leaving turbocharger 1460 is at approximately 0.1 MPa and 750 K. The air and working fluid are then fed into a recuperator 1420, which is a heat exchanger configured to remove heat from the air and working fluid. Hot exhaust from recuperator 1420 at approximately 500 K is provided to a destination to be used for desalination. Working fluid at approximately one MPa and 625 K is then fed back into heat exchanger 1412 to be heated and cycle back though system 1400. The air may also be used to perform fuel-oil combustion via a combustion engine 1430 when reactor is 1410 is not connected. Alternatively, combustion engine 1430 may be used to supplement the heat generation of reactor 1410 in some embodiments. In reactor mode, system 1400 may be altered to allow air to be compressed, heated by the heat pipes coming out of the core of reactor 1410, and then be directed to turbine 1444 in place of air heated by natural gas or diesel fuel via combustion engine 1430, for example. The design changes allow for alternate piping connections that allow reactor 1410 to be attached to system 1400. A gas turbine may be connected by an on-site operator to a heated air outlet from a mobile heat pipe cooled fast reactor, for example. See PCT Application No. PCT/US2014/034102. This realigns the gas turbine to reactor mode, where fossil fuel is not required for its operation. In many embodiments, the generator, regulator, and programmable logic controller (PLC) need not be redesigned. Fuel resources and conventional diesel generators may be needed to achieve the power output of mobile heat pipe cooled fast reactor systems in some embodiments. See PCT Application No. PCT/US2014/034102. In this example, the power requirements are 6 MW. In order to achieve this power output using conventional MEP-011E diesel generators, 30 generators are required, having a pad area of 5,000 square feet. Further, a weekly convoy of six tanker trucks providing 66,000 gallons of fuel is needed to run the generators. However, a mobile heat pipe cooled fast reactor solution only requires three 2 MW reactors, having a pad area of 2,000 square feet. Thus, not only is the need for refueling eliminated, but the space required to deploy the reactors is significantly less than with a diesel generator solution. Furthermore, a smaller size of the power generator site provides a smaller target size to enemy combatants, making the reactors harder to hit with mortars, for example. Further, even if hit, the reactors may be armored as discussed above. Conventional solar equipment and fuel resources may be needed to achieve the power output of mobile heat pipe cooled fast reactor systems in some embodiments. See PCT Application No. PCT/US2014/034102. Solar power does not have 100% availability, i.e., it only works well when there is little or no cloud cover. As such, solar systems require a greater level of generating capacity to offset the lack of energy when the sun is not available. However, nuclear reactors can run 100% of the time, and thus, require less installed capacity relative to solar systems. It will be readily understood that the components of various embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the detailed description of the embodiments of the systems, apparatuses, methods, and computer programs of the present invention, as represented in the attached figures, is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. The features, structures, or characteristics of the invention described throughout this specification may be combined in any suitable manner in one or more embodiments. For example, reference throughout this specification to “certain embodiments,” “some embodiments,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in certain embodiments,” “in some embodiment,” “in other embodiments,” or similar language throughout this specification do not necessarily all refer to the same group of embodiments and the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It should be noted that reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention. One having ordinary skill in the art will readily understand that the invention as discussed above may be practiced with steps in a different order, and/or with hardware elements in configurations that are different than those which are disclosed. Therefore, although the invention has been described based upon these embodiments, it would be apparent to those of skill in the art that certain modifications, variations, and alternative constructions would be apparent, while remaining within the spirit and scope of the invention. In order to determine the metes and bounds of the invention, therefore, reference should be made to the appended claims.
047626666	summary	FIELD OF THE INVENTION The present invention relates to a swing gate closure assembly and more particularly to a swing gate closure assembly for a nuclear reactor which uses hydraulic forces coupled with the weight of the swing gate to provide a foolproof closure mechanism. BACKGROUND OF THE INVENTION When nuclear fuel is depleted, it must, of course, be removed from the reactor process area or core so that it may be replaced with fresh fuel. One current method for effecting removal involves introducing water under pressure into the tube holding the fuel charge. This causes the fuel charge to move through the tube to the end of the tube, where it is expelled. A fuel charge generally comprises about sixteen fuel elements arranged in the tube by spacers at either end. When a charge/discharge operation is not in effect, the reactor tubes are typically sealed by an arrangement such as that shown in FIG. 1. In FIG. 1, the nozzle end of the process tube is indicated by numeral 10. The arrow in outline indicates a direction of flow. Nozzle cap 40 is threaded onto the nozzle 10. The nozzle 10 is also sealed by a seal plate 20 and graphoil seal 30. The seal plate 20 is loaded by three loading bolts 50, two of which are visible in FIG. 1. When it is desired to effect fuel discharge, it is necessary for an operator to remove nozzle cap 40 and seal plate 20. This clears the way for the fuel charge to leave the process tube nozzle 10. A problem which exists, however, is that after the last spacer of the fuel charge has cleared the tube, water which has just traversed the radioactive core gushes out and sprays the operator. This imposes an undesirably high risk of radioactive contamination. It is therefore desirable to provide a mechanism by which the nozzle 10 can automatically close after the final fuel spacer has cleared the tube. At the same time, it is necessary that any such mechanism function extremely reliably given the high safety standards required for nuclear reactor applications. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a reliable closure assembly. It is a further object of the invention to provide a swing gate closure assembly which permits fuel elements to be removed from a reactor core but which is responsive when the last fuel spacer has cleared the tube to swing closed automatically. Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon the examination of the following or may be learned by practice of the invention. To achieve the foregoing and in accordance with the purposes of the invention, as embodied and broadly described herein, there is provided a swing gate closure assembly for a nuclear reactor tip off assembly comprising a closure assembly body having an inlet, an outlet, and a through bore dimensioned to permit passage of a fuel charge therethrough; a swing gate, moveable between a first position in which said swing gate does not seal said through bore and a second position in which said swing gate seals said through bore, is disposed in the closure body. The swing gate is moved to the first position by the fuel charge during passage of the fuel charge through the through bore; the assembly includes a device in the body and in fluid communication with the inlet to hydraulically move the swing gate to the second position when the last fuel spacer of the fuel charge has cleared the through bore. The swing gate closure assembly of the present invention does not obstruct egress of fuel elements or spacers, and is capable of ready, rapid, and reliable closure in the absence of a fuel element or spacer. Closure is not effected through the provision of mechanical closing means, but instead is effected by forces generated by the fluid itself. These forces, coupled with the weight and moments of the swing gate, provide a virtually foolproof closing mechanism.
051125714	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will now be described with reference to FIGS. 1 to 10. As shown in FIGS. 9 and 10, in a fuel assembly for use in a BWR according to present invention, a plurality of fuel rods 1, each consisting of fuel pellets 22 charged into a cell 21 having end plugs 23 welded onto the upper and lower ends thereof, are arranged in arrays, for instance, in eight rows and eight columns, in a channel box 7, with the upper and lower ends of the fuel rods 1 being fixed by tie-plates 8 and 9. A handle 10 is mounted on an upper portion of the assembly. In order to keep the thin, elongated fuel rods 1 correctly spaced from one another, spacer elements of a fuel spacer 2 are disposed in several stages which are vertically separated. As shown in FIG. 7, a round-cell-type fuel spacer 2 has a plurality of cylindrical cells 11 arranged in a grating-like manner. Adjacent cylindrical cells 11 are joined together by welding. As shown in FIG. 1, a fuel rod 1 inserted into a cylindrical cell 11 is supported by two projections 13 and a loop-shaped spring 12, which are provided within the cell 11. The cylindrical cell 11 has vanes 3 for generating swirls, as shown in FIGS. 1 and 2. Each vane 3 is formed by forming a cut in a part of the side wall of the cell 11 so as to separate a portion of the side wall from the cut, and bending the separated portion. The vane 3 thus formed is bent from the cut and projects obliquely outward. As shown in FIG. 7, the vanes 3 are disposed while projecting into the corresponding inter-rod space 5 surrounded by adjacent cylindrical cells 11, the space being substantially rhombic. The number of vanes 3 provided on one cell 11 varies in accordance with the position of the cell 11 in the cell matrix. As shown in FIG. 7, the corner cells each have one (the smallest number) vane, while the cells in inward arrays each have four (the greatest number) vanes. In the spacer 2 having the above-described construction, the vanes 3 cause the generation of swirls of coolant in the spaces between the fuel rods 1, which in turn causes an increased mount of liquid drops to adhere to the fuel rods 1, thereby increasing the thickness of the liquid films on the fuel rods 1. As a result, the transfer of heat from the fuel rods 1 to the liquid films formed by the coolant is promoted. This enables an increase in the critical output, hence, in the allowable power level. The cuts for forming the vanes 3 can be easily formed simultaneously with the formation of the spring portions for holding the fuel rods 1 in place, which are formed by embossing. The formation of the vanes 3, therefore, does not involve the drawback of the prior art where the formation of an oblique groove extending from a lower position to an upper position of the cell is difficult and necessitates an additional process. Another advantage is that, in contrast with the prior art where a guide groove is formed by bending at a sharp angle a portion of the cell cylinder which extends from a lower position to an upper position thereof, a vane 3 is formed by cutting a relatively small part of the side wall of the cell; this assures sufficient strength in the side wall. Furthermore, the degree of pressure loss in the spaces 5 between the fuel rods 1 is low. Still further, the flow of a liquid film between a cell and the fuel rod, that is, the endo-cell flow of liquid film, can be substantially free from disturbance. Although in the embodiment shown in FIG. 2, each vane 3 is formed by cutting an inverted-L-shaped slit in the associated side wall of the cell, the cut will not necessarily have this shape so long as the vanes 3 have tip portions which obliquely project into the corresponding spaces 5 between the fuel rods 1. For instance, each vane may be formed by cutting, for instance, a U-shaped slit. FIGS. 3 and 4 show another embodiment of the fuel spacer according to the present invention. A fuel spacer 2A according to this embodiment has cylindrical cells 11A receiving fuel rods 1. Each cell llA has vanes 3A which are each formed by cutting a vertically extending slit from the upper end of the cell, and bending the separated portion of the side wall of the cell llA in such a manner that it projects outward. If this construction is adopted, it is possible, similarly to the case of the fuel spacer 2, to promote the transfer of heat from the fuel rods to liquid films, thereby raising the allowable power level of the fuel rods 1. Another advantage is that the process of forming the vanes 3A is simpler than that required in the embodiment shown in FIGS. 1 and 2. When a fuel spacer of the same type as the above-described fuel spacer 2 or 2A having vanes of the same type as the vanes 3 or 3A is used in a fuel assembly, the amount of liquid drops flowing in the vapor through the inter-rod spaces 5 decreases in effect as the coolant flows toward the upper ends of the fuel rods 1. This means that the increment in the pressure loss, which the provision of the vanes 3 or 3A entails, rapidly decreases toward the upper ends, till the vicinity of the upper ends of the fuel rods 1 is substantially free from such an increment in the pressure loss. Conversely, in this area, it is of more importance that stronger swirls be generated so as to secure a sufficient amount of liquid films. A fuel assembly capable of meeting this requirement will be described as another embodiment. A fuel assembly of this embodiment has a fuel spacer 2B, of which essential parts are shown in FIG. 5. The fuel spacer 2B has cylinders 4, each being shown in FIG. 6. Specifically, in order to provide vanes, none of the cylindrical cells 11B of the spacers 2B are subjected to direct machining, but thin-walled cylinders 4, each having vanes 3B provided therein, are disposed in the spaces 5 between fuel rods 1 while being fixed to adjacent cylindrical cells 11B. According to this embodiment, since, similarly to the foregoing embodiments, swirls are generated in the cylinders 4, the transfer of heat from the fuel rods 1 to the liquid films is promoted, and the allowable power level of the fuel rods 1 is thus raised. Another advantage is that since the vanes 3B are provided within the cylinders 4, it is possible to design the dimensions and the configuration of the vanes more freely than the foregoing embodiments where portions of the side walls of the cylindrical cells are formed as vanes, and to secure the generation of stronger swirls. The section of the cylinders 4 are not necessarily circular; so long as the degree of pressure loss is as low as possible and the cylinders can be sufficiently firmly fixed to the side walls of the cylindrical cells 11B, the section of the cylinders may be angular. In order to generate still stronger swirls in the vicinity of the upper ends of the fuel rods 1, it is possible to arrange a fuel spacer of a different type in the vicinity of the upper ends of the fuel rods 1, the fuel spacer having spiral vanes 6, each being shown in FIG. 8, instead of the cylinders 4 shown in FIG. 5. When the merit of swirls generated by vanes is balanced against the increment in the degree of pressure loss entailed by the provision of the vanes, it is understood that the vanes may not necessarily be of one type throughout various areas arranged longitudinally of the fuel rods 1. Specifically, it is preferable to dispose an ordinary fuel spacer element having no vanes at a lower stage on the fuel rods where the pressure loss is a factor of importance requiring consideration, while a fuel spacer element having vanes is disposed at an upper stage on the fuel rods where the generation of swirls is a more important factor. It is also possible to dispose an ordinary fuel spacer element having no vanes at a lower stage on the fuel rods, while a vaned fuel spacer element of the type 2 or 2A is disposed at an intermediate stage on the fuel rods, and a vaned fuel spacer element which is either of the type 2B or of the type provided with the spiral vanes (shown in FIG. 8) is disposed at an upper stage of the fuel rods. Within the section of the fuel spacer shown in FIG. 7, the fuel rods in the arrays closest to the outer periphery of the fuel spacer as well as those in the arrays second to the closest are exposed to a thermally severe condition when compared to others. Therefore, vanes may be disposed only in the spaces surrounded by the fuel rods in these arrays. According to the present invention, vanes disposed in the spaces between the fuel rods generate swirls. Therefore, the transfer of heat from the fuel rods serving as the heat source to the coolant is promoted, thereby raising the allowable power level of the fuel assembly. Also, the void ratio is lowered, thereby increasing the reactivity. The fuel spacer according to the present invention, which achieves these advantages, is such that either vanes are formed by simply bending portions of the side walls of the cells of the spacer, or the spacer itself is not subjected to any direct machining and separate members, i.e., cylinders having built-in vanes or spiral vanes, are fixed to the spacer. Therefore, in contrast with the prior art where guide grooves are obliquely formed from lower positions to upper positions of the cells of the spacer, it is possible to assure a sufficient strength for performing the fundamental function of a fuel spacer which is to maintain fuel rods in their correct position. In the type where vanes are formed by directly subjecting the spacer cells to machining, vanes are formed simultaneously with the embossing of the spacer cells and by cutting parts of the side walls of the spacer cells and bending portions of the side walls from the cuts. Therefore, the manufacture of the spacer remains simple.
062263544	claims	1. A short-wavelength electromagnetic-radiation generator comprising: reflector means composed of at least a pair of concave reflectors; emitting means for emitting electromagnetic radiation so as to be incident on said reflector means; and electron-beam generating means for emitting an electron beam, said electron beam being emitted in a direction substantially parallel to said reflector-means so as to be incident on said electromagnetic radiation. reflector-means composed of at least a pair of concave reflectors; electron-beam generating means for emitting an electron beam, said electron beam being emitted in a direction substantially parallel to said reflector-means and having a diameter adjusted to a diameter of electromagnetic radiation converged by said at least a pair of concave reflectors in said reflector means so that said electron beam is incident on a region where said electromagnetic radiation is converged by said pair of concave reflectors; and emitting means for emitting said electromagnetic radiation as a pulse beam having a pulse width corresponding to the diameter of said electron beam so as to be incident on said reflector means. 2. A short-wavelength electromagnetic-radiation generator according to claim 1, wherein said reflector means comprises concave reflector groups disposed to be opposed, each concave reflector group being composed of a plurality of aligned concave reflectors. 3. A short-wavelength electromagnetic-radiation generator comprising: 4. A short-wavelength electromagnetic-radiation generator according to claim 3, wherein said reflector means comprises concave reflector groups disposed to be opposed, each concave reflector group being composed of a plurality of aligned concave reflectors. 5. A short-wavelength electromagnetic-radiation generator according to claim 3, wherein said emitting means comprises a Q-switched laser source. 6. A short-wavelength electromagnetic-radiation generator according to claim 3, wherein said emitting means comprises a mode-locked laser source. 7. A short-wavelength electromagnetic-radiation generator according to claim 4, wherein said emitting means comprises a Q-switched laser source. 8. A short-wavelength electromagnetic-radiation generator according to claim 4, wherein said emitting means comprises a mode-locked laser source.
	description	This is a continuation of application Ser. No. 10/062,666, filed Feb. 5, 2002, entitled “PATTERN INSPECTION METHOD AND SYSTEM THEREFOR”, by T. HIROI, the contents of which are incorporated herein by reference. The present invention is related to a system for the manufacture of a substrate having a circuit pattern, such as a semiconductor device or liquid crystal display; and, more particularly, the invention relates to technology for inspecting a substrate pattern during fabrication. Conventional optical or electron beam pattern inspection systems are described in Japanese Patent Laid-open No. H5-258703 and Japanese Patent Laid-open No. H11-160247. FIG. 1 shows the constitution of a system disclosed in Japanese Patent Laid-open No. H5-258703 as an example of an electron beam pattern inspection system. In this system, an electron beam 2 from an electron beam source 1 is deflected in the X direction by a deflector 3 and is irradiated onto a target substrate 5 via an object lens 4, while a stage 6 is simultaneously made to move continuously in the Y direction. Secondary electrons 7 from the target substrate 5 are detected by a detector 8, and the detected signal is converted from analog to digital by an analog-to-digital (A/D) converter 9 to form a digital image, which is compared in an image processing circuit 10 to a digital image of a place that can be expected to be the same as the original, a place that differs is detected as a pattern defect 11, and the location of the defect is established. FIG. 2 shows the constitution of the system disclosed in Japanese Patent Laid-open No. H11-160247 as an example of an optical inspection system. In this system, a light from a light source 21 is irradiated onto a target substrate 5 via an object lens 22, and a reflected light is detected by an image sensor 23 at that time. By repeatedly detecting the reflected light while a stage 6 moves at a constant speed, an image is detected as a detected image 24, and this image 24 is stored in memory 25. The detected image 24 is compared with a memory stored image 27, which can be expected to have the same pattern as the detected image 24, and if the patterns are identical, the detected image 24 is determined to be a normal portion. However, but if the patterns differ, this difference is detected as a pattern defect 11, and the defect location is established. As an example, FIG. 3 shows a layout of a wafer 31 which represents a target substrate 5. Dies 32, which are ultimately cut apart to yield individual products of the same variety, are formed on wafer 31. Stage 6 is moved along a scanning line 33, and an image of the stripe region 34 is detected. When the present detection location A is at 35, an image of detection location B 36 in memory 25 is extracted as a stored image 27, and the two images are compared. Thereby, detection location A 35 is compared against a pattern that can be expected to be an identical pattern. Here, memory 25 possesses a capacity capable of holding an image that can be expected to be an identical pattern, that is used repeatedly in a ring shape to form an actual circuit. In the case of both inspection systems, to confirm the results of the inspection, the inspected data is outputted to a review system. Thereafter, the wafer is transferred to and set on a table of the review system to review defects detected by the inspection system. In the review system, the defect to be reviewed is placed in a viewing field of the review system by using the inspected data outputted from the inspection system. Then, the image is visually observed to judge whether or not it has an actual defect or to infer what could have caused it. In such a reviewing method, a vast amount of image data acquired during the inspection is not effectively used. The present invention is constituted such that an image of a defect portion, which is similar to an image of a defect portion specified on the basis of inspection results outputted by an inspection system, and the defect portion image data thereof, is retrieved, and the conditions for the occurrence of a specific mode defect, which have occurred in the past, can be identified by displaying the retrieval results, so as to enable identification. A first system according to the present invention will be explained. A constitution of a system that uses an electron beam will be considered, but there is substantially identical to a system which utilizes another type of charged particle. As seen in FIG. 4, the system is constituted from an electron beam source 1 for generating an electron beam 2; a deflector 3 for deflecting the electron beam 2; an object lens 4 for converging the electron beam 2 onto a target substrate 5; and a stage 6 for holding, scanning and positioning the target substrate 5. A detector 8 is grounded for detecting secondary electrons 7 emitted from the target substrate 5; and, an A/D converter 9 operates to convert a detected signal from analog to digital to form a digital image. An image processing circuit 110 compares the digital image against a digital image of a location that can be expected to be substantially identical and detects a location that is different as a pattern defect 11. Defect data storing means 201 operates to store defect data 200 comprising the defect location and image data of the pattern defect 11; and data outputting means 203 outputs the stored defect data 202 to either a network or a storage medium. An inputting means 205 is provided for inputting defect data 202 related to a plurality of wafers, which was outputted to data transferring means 204 by data outputting means 203; and defect data storing means 206 stores the inputted defect data. A defect map 207 operates to display defect location data of the wafer on a display screen and selecting means 208 selects a specific defect on the defect map 207. Image displaying means 209 displays the image of the selected defect data in an image format. Search command means 210 is provided for issuing a command for retrieving, from the defect data group a defect image that is similar to a displayed image; and image retrieving means 211 operates to retrieve an image having image data that is similar to a displayed image. The electron beam 2 from electron beam source 1 is irradiated onto target substrate 5 via object lens 4, and generated secondary electrons 7 are detected by the detector 8. In this operation, the electron beam 1 is deflected by deflector 3, image data is formed by using stage 6 for scanning target substrate 5, the image data detected by the detector is converted from analog to digital by A/D converter 9, so that a digital image is formed. Image processing circuit 110 compares this digital image with a digital image which is expected to be substantially identical, and detects a difference between the two images as a pattern defect 11. Defect data 200, comprising the defect location and image data of the detected pattern defect 11, is stored in defect data storing means 201, and stored defect data 202 is outputted by data outputting means 203 as necessary to information transferring means 204 in the form of either a network or a storage medium. Defect data 202 of a plurality of wafers, which is outputted from outputting means 203, is inputted by inputting means 205 and is stored in a storing means 206, and the defect location data of the inputted defect data is displayed on defect map 207. When a specific defect on the defect map is selected by selecting means 208, an image of the selected specific defect is displayed on image displaying means 209. When a command is issued by search command means 210, a defect image similar to the displayed image is retrieved from among the stored defect data stored in the storing means 206 by image retrieving means 211, and the retrieval results are reflected in defect map 207. Retrieval results can be checked as needed by issuing a command via selecting means 208. The frequency at which similar defects occur can be checked by displaying in the time-series format shown in FIG. 5, a display format of defect map 207. In accordance therewith, the image data acquired at inspection time can be utilized effectively. These and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. The embodiments of the present invention will be explained hereinbelow using specific figures. The overall system will be explained first, and then the respective parts of the system will be explained. (Overall System) The constitution of a first embodiment of the present invention is shown in FIG. 6. This first embodiment is constituted from a server 151, which is arranged on a network 150 and which manages and stores various information; an SEM (scanning electron microscope) type pattern inspection system, an optical type pattern inspection system, an extraneous material inspection system, a length-measuring SEM, and other such inspection systems A 152 and inspection systems B 153, which treat a target substrate 5 as an object, and inspect patterns and measure dimensions; a review system 154 for receiving inspection results from inspection system A 152 and inspection system B 153, fir positioning target substrate 5 at a specified defect location, and for visually checking this specified defect; and a defect checking system 155 for receiving and checking either inspection or measurement data at inspection time. The respective parts satisfy their functionality by operating as described hereinbelow. That is, a target substrate is loaded, and either a pattern inspection or an extraneous material inspection is carried out, or pattern dimensions are measured by inspection system A 152 and inspection system B 153. Measurement results, together with image data of defective parts and measured portions are stored when inspection and measurement are performed, and the measurement results and image data are outputted over network 150. This data is stored in server 151 at one time. Information of the measurement results and image data of a plurality of target substrate stored in server 151 is transmitted to defect review system 154, and measurement results are displayed on defect confirmation system 155. Based on the displayed results, image data of a defective portion, which is similar to the image of a specific defect, is retrieved using a method which will be explained hereinbelow, and the retrieval results are reflected on a display. A first variation of this embodiment will be explained. That is, instead of executing a search via a defect checking system 155, a search can be executed via either inspection system A 152, or inspection system B 153, or server 151, or review system 154. Or, instead of the checking system 155, a search server 156, which is connected to the network 150, is provided, a search is executed by the search server 156, and only the results are displayed via a system other than defect checking system 155 or search server 156. Further, a search can be executed by an arbitrary system without the need to provide search server 156 independently. (Inspection System) The constitution of a SEM-type pattern inspection system is shown in FIG. 7. This system comprises an electron beam source 1 having an electron gun for generating an electron beam 2; and an electron optical system 64 for accelerating and extracting the electron beam 2 from electron beam source 1 by means of an electrode, and which creates a virtual light source in a fixed location by means of an electrostatic or magnetic field superimposed lens. The electron optical system 64 includes a condenser lens 60 for converging the electron beam 2 from the virtual light source in a fixed location; a blanking plate 104, which is set near the convergence location, and which effects ON/OFF control of the electron beam 2 emitted from the electron gun; a deflector 105 for deflecting an electron beam 2 in XY directions; and an object lens 4 for converging the electron beam 2 onto a target substrate 5. A sample chamber 107 is evacuated for maintaining a wafer 31, which is the target substrate 5, in a vacuum; a stage 6, on which the wafer 31 is mounted, is located in the sample chamber 107, and a retarding voltage 108 is applied thereto for making it possible to detect an image of an arbitrary location. A detector 8 detects secondary electrons 7 emitted from target substrate 5; and an A/D converter 9 is provided for converting a signal detected by detector 8 from analog to digital and producing a digital image. A memory 109 is connected to the converter 9 for storing the digital image; and an image processing circuit 110 operates to compare data image stored in memory 109 with an A/D converted digital image and to detect the difference between the compared images as a pattern defect 11. A pattern defect storage portion 201, is provided for storing defect data 200, such as pattern defect 11 coordinates, projected length, area, critical threshold value DD (the threshold value at which, when the threshold value is lower than this value, a defect is detected), differential image average value, differential image distribution, maximum image difference, defect image texture, reference image texture, image of a defect portion, and a reference image having a pattern that is identical to that of the defect portion. Data outputting means 203 is connected to the pattern defect storage portion 201 for outputting stored defect data 200 to either a network or a storage medium. A system controller 100 is provided for controlling the entire system (control lines from system controller 100 are omitted from the figure); and a display unit is connected to the system controller 100. The display unit includes an operating screen 45 for performing various operations, a keyboard (not shown), a mouse (not shown)and a knob (not shown) for specifying operations. A Z sensor 113 is provided for maintaining the focal point position of a detected digital image constant by measuring the height of a wafer 31 and adding and controlling an offset 112 to the current value of object lens 4. A loader (not shown) is provided for loading and unloading wafers 31 carried in a cassette 114 into sample chamber 107; and an orientation flat detector (not shown) is provided for positioning the wafer 31 using the outline shape of the wafer 31 as a reference. An optical microscope 118 is provided for observing a pattern on the wafer 31; and a standard sample 119 is provided on stage 6. The operation of the inspection system will be explained. When an inspection is started by a command from a user, stage 6 moves and the region to-be-inspected on the wafer 31 mounted on the stage 6 is moved to the scanning start position. A wafer-specific offset measured beforehand is added and set in offset 112, Z sensor 113 is made operative, stage 6 scans in the Y direction along scanning line 33 shown in FIG. 3, deflector 105 scans in the X direction in synchronization with the scan of the stage, the voltage of blanking plate 104 is shut off at the effective scanning time, and an electron beam 2 is irradiated onto the wafer 31 and scanning is performed. Either reflected electrons or secondary electrons generated from wafer 31 are detected by detector 8, a digital image of stripe region 34 is produced by A/D converter 9, and this digital image is then stored in memory 109 and inputted in image processing circuit 110 in parallel. Upon termination of the scan of stage 6, Z sensor 113 is made inoperative. An inspection of all required regions is carried out by repeating the scanning of the stage 6. When the detection is carried out in the location A 35 (Refer to FIG. 3), image processing circuit 110 compares a detected image of the location A 35 with an image of detection location B 36 (Refer to FIG. 3) stored in memory 109, and extracts a discrepancy between both images as a pattern defect 11, and the image of detection location A 36 is stored in defect data storage means 201. Defect data 200, such as extracted pattern defect 11 coordinates, projected length, area, critical threshold value DD (the threshold value at which, when the threshold value is lower than this value, a defect is detected), differential image average value, differential image distribution, maximum image difference, defect image texture, reference image texture, and image data, is stored in defect data storage means 201. And, from data outputting means 203, data is outputted as needed to data transferring means 204, which is either a network or an MO (magneto-optical disk), CDR (compact disk-recordable), DVD (digital video disk), FD (floppy disk) or other storage medium. (Results Confirmation System) Outputted defect data 202 is inputted via inputting means 205 (See FIG. 4) of results confirmation system 155 either via a network or from a storage medium, and defect location data from among the inputted defect data is displayed on defect map 207. When a specific item on the defect map is selected by selecting means 208, image data of the defect data is displayed in a image format on image displaying means 209. When a command is issued by search command means 210, a defect image similar to the display image is retrieved by image retrieving means 211 from among the defect data group, and retrieval results are reflected on defect map 207. Retrieval results can be checked as needed by issuing a command via selecting means 208. The frequency at which similar defects occur can be checked by displaying in the time-series format shown in FIG. 5, a display format of the defect map 207. In accordance therewith, the image data acquired at inspection time can be utilized effectively. An example of a display screen of the results confirmation system 155 is shown in FIG. 8. The location on a substrate (wafer) of each detected defect is displayed on map display portion 55, which corresponds to defect map 207 of FIG. 4. Further, an image of a defect specified from among the defects displayed on the map display portion 55 is displayed on image display portion 56, which corresponds to image displaying means 209 of FIG. 4. Specifying a defect for displaying this image is effected by operating a mouse operation command button 140. That is, a current location symbol 59 is displayed on the screen using the mouse operation command button 140 to select a selection mode 145 from among a selection mode 145 and a zooming mode 146, the current location display 59 is moved with the mouse (not shown in the figure), and the image of a defect that a user wishes to see is displayed on image display portion 56 by clicking on the location of the defect to be viewed. Further, when the zooming mode 146 is selected with the mouse operation command button 140, a display on map display portion 55 of the distribution of defects on a substrate can be either enlarged or reduced. According to the present invention, an image of a defect portion, which is similar to an image of a defect portion specified on the basis of inspection results outputted by an inspection system and the defect portion image data thereof, is retrieved, and the conditions for the occurrence of a specific mode defect, which occurred in the past, can be identified by displaying the retrieval results so as to enable identification. Further, the present invention is characterized in that it enables the provision of functions for sounding an alarm in response to a future specific mode-generated defect by setting retrieval conditions in the inspection system. The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
	claims	1. A mitigation assembly for a nuclear reactor, comprising a box with a longitudinal axis, the box comprising a central portion in which corium circulates and an upper portion housing an upper neutron shielding device, wherein the upper neutron shielding device comprises an upper neutron shielding head supporting neutron absorbers, wherein the upper neutron shielding device comprises removable locking means configured to cooperate with the box, wherein the upper neutron shielding device comprises a slug being free to move in translation over a given travel distance, the locking means being configured to lock and unlock the upper neutron shielding head with the box by displacement of the slug along the longitudinal axis with a grab for extraction of the upper neutron shielding device with pawls of the grab attached in the slug,wherein the upper portion of the box also comprises a cone-shaped sealing block with the tip of the cone oriented towards the bottom of the box, cooperating with a cone-shaped internal surface of the box, a seal being formed between the sealing block and the internal surface of the box. 2. The assembly according to claim 1, wherein the upper portion of the box also comprises an intermediate sealing block located between the upper neutron shielding head and the cone-shaped sealing bock. 3. The assembly according to claim 2, wherein the cone-shaped sealing block and/or the intermediate sealing block are made of metal or contain neutron absorbers. 4. The assembly according to claim 1, wherein the space between the cone-shaped sealing block and the internal cone-shaped surface of the box is zero. 5. The assembly according to claim 1, wherein the tip of the cone of said cone-shaped sealing block has a rounded shape. 6. The assembly according to claim 1, wherein the locking means are composed of other pawls installed free to pivot in a vertical plane. 7. The assembly according to claim 6 wherein the box comprises an internal groove in which the pawls of the locking means can be inserted to form an upper stop for the upper neutron shielding device. 8. The assembly according to claim 1, wherein the slug comprises an internal groove in which the pawls of the grab can be attached. 9. The assembly according to claim 1, wherein the upper neutron shielding device comprises one or several hollow columns passing through the slug. 10. A nuclear reactor, comprising at least one mitigation assembly according to claim 1.
	claims	1. A laser produced plasma type extreme ultraviolet light source apparatus for generating extreme ultraviolet light by applying a laser beam to a target material, said apparatus comprising:a chamber in which extreme ultraviolet light is generated;target supply means for supplying a target material to a predetermined position within said chamber;a laser beam focusing optics for focusing a laser beam from a driver laser using a laser gas containing a carbon dioxide gas as a laser medium, for applying a laser beam to the target material supplied by said target supply means to generate plasma;a collector mirror for collecting the extreme ultraviolet light radiated from the plasma to output the extreme ultraviolet light;a spectrum purity filter provided in an optical path of the extreme ultraviolet light from said collector mirror, for transmitting the extreme ultraviolet light and reflecting the laser beam, said spectrum purity filter including a mesh having electrical conductivity; anda holder for holding a circumference of said mesh, said holder being formed with a channel for passing, along with the circumference of said mesh, a medium for cooling or heating said holder. 2. The extreme ultraviolet light source apparatus according to claim 1, wherein said mesh has a square-lattice form. 3. The extreme ultraviolet light source apparatus according to claim 1, wherein said mesh has a honeycomb form. 4. The extreme ultraviolet light source apparatus according to claim 1, wherein said spectrum purity filter includes a mesh coated with a material having electrical conductivity on at least a surface thereof. 5. The extreme ultraviolet light source apparatus according to claim 4, wherein said spectrum purity filter includes a mesh coated with a material having electrical conductivity on at least a light incident surface thereof. 6. The extreme ultraviolet light source apparatus according to claim 5, wherein said mesh contains one of diamond, diamond-like carbon, silicon carbide, and silicon. 7. The extreme ultraviolet light source apparatus according to claim 5, wherein said material having electrical conductivity contains one of gold and molybdenum. 8. The extreme ultraviolet light source apparatus according to claim 4, wherein said mesh contains one of diamond, diamond-like carbon, silicon carbide, and silicon. 9. The extreme ultraviolet light source apparatus according to claim 4, wherein said material having electrical conductivity contains one of gold and molybdenum. 10. The extreme ultraviolet light source apparatus according to claim 1, wherein said holder holds said mesh such that a surface of said mesh is flat. 11. The extreme ultraviolet light source apparatus according to claim 1, further comprising:a mechanism for rotating or vibrating said holder. 12. The extreme ultraviolet light source apparatus according to claim 1, wherein said chamber is configured to introduce an etchant gas, said etchant gas contains at least selected one from a hydrogen gas, halogen gas, hydrogen halide and argon gas.
	abstract	The disclosure is made for an apparatus for processing a radiation image of an object obtained by radiography using a grid which is used to remove scattered radiation from the object.
	description	Technical Field The present invention relates generally to a system and method for removing radon from the environment. Description of the Related Art Radon gas is a naturally occurring radioactive noble gas. It has long been recognized that exposure to radon gas (and radon gas “daughters” that occur as a result of radon gas decay) can pose a significant health hazard. Although testing for radon gas has been performed for many years, until recently, concern over exposure to radon gas was primarily associated with workers in the uranium mining industry or others whose work brought them in contact with uranium ore. In recent years, it has been recognized that radon gas can seep out of the ground through building foundations and can accumulate inside buildings. When radon gas accumulates in a human environment, it can be inhaled, thereby exposing the lungs to radioactivity. In accordance with an embodiment, a system is provided for collecting and removing radon from a confined area. The system includes at least one collector for collecting radon from the confined area, a plurality of radon adsorbers each connected to a corresponding power supply, a plurality of valves for diverting the collected radon through one or more of the plurality of radon adsorbers, and a plurality of radon storage units for receiving radon held by the plurality of radon adsorbers for a predetermined period of time. In accordance with an embodiment, a method is provided for collecting and removing radon from a confined area. The method includes collecting radon from the confined area via at least one collector, connecting each of a plurality of radon adsorbers to a corresponding power supply, diverting, via a plurality of valves, the collected radon through one or more of the plurality of radon adsorbers, and receiving, via a plurality of radon storage units, radon held by the plurality of radon adsorbers for a predetermined period of time. In accordance with another embodiment, a method is provided for collecting and removing radon from a confined area. The method includes incorporating a plurality of radon adsorbers within a structure of the confined area, negatively biasing the plurality of radon adsorbers within the structure, and attracting the radon on surfaces of the plurality of radon adsorbers. In accordance with another embodiment, a wearable article for repelling radon is presented. The wearable article includes an inner protective layer having an inner surface and an outer surface, the inner surface configured to contact a user and an outer protective layer configured to contact at least a portion of the outer surface of the inner protective layer. The outer protective layer repels radon. It should be noted that the exemplary embodiments are described with reference to different subject-matters. In particular, some embodiments are described with reference to method type claims whereas other embodiments have been described with reference to apparatus type claims. However, a person skilled in the art will gather from the above and the following description that, unless otherwise notified, in addition to any combination of features belonging to one type of subject-matter, also any combination between features relating to different subject-matters, in particular, between features of the method type claims, and features of the apparatus type claims, is considered as to be described within this document. These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. Throughout the drawings, same or similar reference numerals represent the same or similar elements. Embodiments in accordance with the present invention provide methods and devices for collecting and removing a noble gas from a confined area. The noble gas can be, e.g., radon. Radon is a chemical element with symbol Rn and atomic number 86. It is a radioactive, colorless, odorless, tasteless noble gas, occurring naturally as a decay product of radium. Radon's most long-lived isotope, 222Rn has a half-life of 3.8 days. This isotope of radon is formed as one intermediate step in the normal radioactive decay chain through which uranium slowly decays into a stable isotope of lead, 206Pb. Unlike all the other intermediate elements, radon is gaseous and easily inhaled. Thus, naturally-occurring radon is responsible for the majority of public exposure to ionizing radiation. Radon is often the single largest contributor to an individual's background radiation dose, and is most variable from location to location. Despite its short lifetime, some radon gas from natural sources can accumulate to far higher than normal concentrations in buildings, especially in low areas such as basements and crawl spaces due to its heavy nature. As radon itself decays, it produces new radioactive isotopes called radon daughters or decay products or radon progeny. Unlike gaseous radon itself, radon daughters are solids and stick to surfaces, such as dust particles in air. If such contaminated dust is inhaled, these particles can stick to airways of the lung and increase a risk of developing lung cancer. Embodiments in accordance with the present invention provide methods and devices for collecting and removing or sequestering radon. If radon is sequestered for a number of days, then radon could be converted to a solid which results in a 10,000 volume reduction. Embodiments in accordance with the present invention provide methods and devices for implementing air handling filters for collecting and removing or sequestering radon from a structure, such as a building. A series of biased metal meshes, gas flow collectors, and diverting valves can be used to divert gas or radon from a building or home by electrodes where they are negatively biased to collect the radon (Rn). This enables collection of Rn as opposed to simply venting it to the outdoors. Embodiments in accordance with the present invention provide methods and devices for creating a biased mesh to be incorporated or embedded within clothing, sports equipment, and first responders' gear to prevent Rn from adsorbing to the surface of such wearable articles and/or items. The majority of Radon daughter isotopes have a positive electrical charge. Thus, devices can be used to repel or attach the daughters based on their electrical charge. As a result, toxic species are not adhered to outer surfaces of clothing, equipment, and/or gear that would easily be breathed in immediately after, e.g., a fire. The biased mesh can be used in clothing or equipment or gear related to a number of recreational or sports activities, as well as in compression bonds, breathing apparatuses, where the metal mesh is positively biased to repel Rn. Embodiments in accordance with the present invention provide methods and devices for implementing metal mesh in concrete structures. For example, metal meshes can be negatively biased, to attract the radon daughters, and can be incorporated or embedded within concrete structures. Rn in the atmosphere or environment can be adsorbed onto or in proximity to the metal mesh. The polarization of the metal mesh can be maintained negatively for weeks, months, or years at a time. The half-life of 222Rn is 3.8 days. The decay products are solids. Thus, it is only necessary to maintain the Rn long enough to allow the decay process to convert radon gas to solid materials that can no longer cause a threat. Embodiments in accordance with the present invention provide methods and devices for implementing radon detectors that are made with biased meshes to collect and allow Rn to form a solid. After enough time, the meshes could either be sent to a lab to test or measured locally. It is to be understood that the present invention will be described in terms of a given illustrative architecture; however, other architectures, structures, substrate materials and process features and steps/blocks can be varied within the scope of the present invention. It should be noted that certain features cannot be shown in all figures for the sake of clarity. This is not intended to be interpreted as a limitation of any particular embodiment, or illustration, or scope of the claims. Various illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this invention. FIG. 1 is a filtration system for collecting and removing radon from a confined area, in accordance with an embodiment of the present invention. The filtration system 10 includes a plurality of collectors 12, 14, 16. The plurality of collectors 12, 14, 16 are configured to collect radon, from the atmosphere or environment. The filtration system 10 further includes a plurality of diverting valves 20, 22, 24. The filtration system 10 also includes a first metal mesh 40 and a second metal mesh 42. The first metal mesh 40 is connected to a first power supply 30 via cables 31 and the second metal mesh 42 is connected to a second power supply 32 via cables 33. The first metal mesh 40 is connected between the first diverting valve 20 and the second diverting valve 22, whereas the second metal mesh 42 is connected between the first diverting valve 20 and the third diverting valve 24. Radon can flow from the first diverting valve 20, via channel 5, to the first metal mesh 40 and radon can flow from the first diverting valve 20, via channel 7, to the second metal mesh 42. The filtration system 10 also includes a plurality of radon storage units 50, 52. The storage units can be, e.g., zeolite chambers 50, 52. The first zeolite chamber 50 is connected between the radon collector 14 and the second diverting valve 22, whereas the second zeolite chamber 52 is connected between the radon collector 16 and the third diverting valve 24. The zeolite chambers 50, 52 are configured to store radon 11. The filtration system 10 also includes a main air handler 60 through which air is output 62 without radon since the radon has been either attracted to the first and second metal meshes 40, 42 or sequestered within the zeolite chambers 50, 52. In operation, in a first stage, the diverting valves 20, 22, 24 are configured such that air flows through the channel 5. Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In operation, in a second stage, the diverting valves 20, 22, 24 are configured such that air flows through channel 7. Thus, the collector 12 collects air with radon and supplies it to the second metal mesh 42 via channel 7. The second metal mesh 42 is biased via the second power supply 32. For example, the second metal mesh 42 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In the meantime, the first power supply 30 is reverse biased (to be regenerated). For example, the first power supply 30 is positively biased such that the collected radon daughters is now repelled from the first metal mesh 40. The collector 14 causes the repelled radon daughters to travel to the first zeolite chamber 50 where it is stored. The radon daughters 11 travel to the first zeolite chamber 50 via channel 15. The radon daughters 11 are sequestered in the first zeolite chamber 50. After all the radon daughters 11 are repelled from the first metal mesh 40 and stored in the first zeolite chamber 50, the diverting valves 20, 22, 24 can be configured back to their original configuration. In operation, in a third stage, the diverting valves 20, 22, 24 are configured such that air flows back through channel 5 (and air supply through channel 7 is cut off). Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is once again negatively biased (switched back from the positive change in the second stage) in order to one again collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. Of course, it is contemplated that the reverse is true. For example, the first stage can involve diverting valves 20, 22, 24 to be configured such that air flows through the channel 7. Thus, the collector 12 collects air with radon and supplies it to the second metal mesh 42 via channel 7. The second metal mesh 42 is biased via the second power supply 32. For example, the second metal mesh 42 is negatively biased in order to collect or attract any radon daughters detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. Thereafter, in the second stage, the diverting valves 20, 22, 24 can be configured such that air flows through channel 5. Thus, the collector 12 collects air with radon and supplies it to the first metal mesh 40 via channel 5. The first metal mesh 40 is biased via the first power supply 30. For example, the first metal mesh 40 is negatively biased in order to collect or attract any radon detected within the air collected by the collector 12. The remainder of the air flows to the main air handler 60 and is output 62. In the meantime, the second power supply 32 is reverse biased (to be regenerated). For example, the second power supply 32 is positively biased such that the collected radon daughters are now repelled from the second metal mesh 42. The collector 16 causes the repelled radon daughters to travel to the second zeolite chamber 52 where it is stored. The radon daughters 11 travel to the second zeolite chamber 52 via channel 17. The radon daughters 11 are sequestered in the second zeolite chamber 52. After all the radon daughters 11 are repelled from the second metal mesh 42 and stored in the second zeolite chamber 52, the diverting valves 20, 22, 24 can be configured back to their original configuration. In one exemplary embodiment, a monitoring system or a detecting device can be positioned at the output of the first and second zeolite chambers 50, 52 that periodically charge another metal mesh negatively (not shown) to monitor, e.g., alpha particle emissions. In this way, it can be determined whether the zeolite of the zeolite chambers 50, 52 is full and needs to be replaced. In another exemplary embodiment, the radon daughters can be held by the metals meshes 40, 42 or the zeolite chambers 50, 52 for example for 30 days (approximately seven ½-lives). The zeolite chambers 50, 52 can be replaced every 30 days or 60 days or 90 days, etc. One skilled in the art can contemplate a plurality of different scenarios for replacing the zeolite chambers 50, 52. In another exemplary embodiment, the metal meshes 40, 42 can simply be discarded from this configuration. FIG. 2 is a biased metal mesh to be used in clothing, equipment, and gear, in accordance with another embodiment of the present invention. The metal fibers 70 can include a core 72 and a casing 74. The core 72 can be constructed from a first metal, whereas the casing 74 can be constructed from a second metal, where the first and second metals are different. When two conductors are placed together, the electrons are free to move and cause the stack to come to a same Fermi level. This leads to one of the metals being positively biased and the other negatively biased. Thus, by placing the metal with a lower Fermi level in the core 72, it leads to the metal on the outer casing 74 to become positively biased. The core metal 72 can be, e.g., a variety of different steel or steel alloys. The casing metal 74 can be, e.g., zinc (Zn). The thickness of the casing 74 can be from about 5 nm to about 100 nm. These metal fibers 70 can be combined to form a metal mesh 70′. The metal mesh 70′ can be constructed as a fabric as shown in 70″. The fabric 70″ can be used in clothing or equipment or gear. The equipment can be, e.g., recreational equipment or sports equipment or camping equipment. The gear can be, e.g., military gear or first responder gear. Of course, one skilled in the art can contemplate incorporating the biased mesh into any type of clothing, garments, articles, apparel, outfits, equipment, gear, accessories, fixtures, appliances, machinery, tools, supplies, etc. The biased mesh would prevent radon daughters from adsorbing to the surface of such items by creating a positive charge via the casing 74. This is especially important if the equipment or gear is stored for any great length of time. FIG. 3 is a metal mesh incorporated in concrete structures and connected to at least one power supply for adsorbing radon daughters, in accordance with another embodiment of the present invention. The system 80 depicts a concrete structure 82 including a plurality of rods or shafts 84 (or connecting members) that are interconnected to hold and stabilize the metal mesh 86. At least one power supply 90 can be connected to the metal mesh 86 via cables 92. When the metal mesh 86 is negatively biased by the at least one power supply 90, radon daughters 88 are adsorbed or attracted to the outer surface of the concrete structure 82. The polarization can be maintained negatively for days or weeks or months or even years. The radon 88 can be continuously collected on the outer surface of the concrete structure where it can become solid after a predetermined time period. It is only necessary to maintain the Rn long enough to allow the decay process to convert the gas to a solid that can no longer cause a threat via inhalation. FIG. 4 is a metal mesh incorporated in concrete structures and coated with a metal for adsorbing radon daughters, in accordance with another embodiment of the present invention. The system 100 depicts a concrete structure 82 including a plurality of rods or shafts 84 (or connecting members) that are interconnected to hold and stabilize the metal mesh 86. The metal mesh 86 can be coated with a plurality of metal fibers 110, where each metal fiber 110 includes a core 112 and a casing 114. The metal mesh 86 can be permanently negatively biased by the metal fibers 110 coated thereon, and thus radon daughters 88 are adsorbed or attracted to the outer surface of the concrete structure 82. The polarization can be maintained negatively for days or weeks or months or even years. The radon daughters 88 can be continuously collected on the outer surface of the concrete structure where it can become solid after a predetermined time period. The core 112 can be constructed from a different variety of steel or steel alloys. The casing metal 114 can be, e.g., iron-nickel (NiFe) alloy or nickel-phosphorus (NiP) alloy. The thickness of the casing 114 can be from about 5 nm to about 100 nm. In another exemplary embodiment, the metal meshes can be biased by other means, such as a battery or capacitor or galvanic couples. FIG. 5 is a block/flow diagram of an exemplary method for collecting and removing radon from a confined area, in accordance with an embodiment of the present invention. At block 202, a plurality of radon adsorbers are incorporated or embedded within a structure of a confined area. The structure can be, e.g., a building. At block 204, the plurality of radon adsorbers are negatively biased within the structure (via one or more power supplies or by coating the plurality of radon adsorbers with a metal having a core (first metal) and a coating (second metal)). At block 206, the radon detected within the confined area on surfaces of the plurality of radon adsorbers is attracted to the plurality of radon adsorbers. In summary, radon (Rn) daughters adsorb to negatively biased species, even though it is a neutral species itself. Rn converts to a solid within 4 days (half-life of 3.8 days). In one exemplary embodiment, surfaces of metal meshes can be modulated by, e.g., a power supply connected thereto, to attract radon and convert it to a solid by holding it biased for a predetermined period of time. Alternatively, the surfaces of metal meshes can be modulated to attract radon daughters and to concentrate it by reversing the charge of the power supply to have the radon daughters flow into zeolite chambers (or other metal mesh) for long-term storage. Once all the radon daughters have been transferred to the long-term storage units or chambers, the power supply can be reversely connected to the metal mesh so that the metal mesh is negatively biased to re-collect new Rn by one or more collectors. In another exemplary embodiment, metal mesh can be incorporated or embedded within or attached to outer surfaces of clothing or equipment or gear such that the surface charge is positive to repel Rn. The metal mesh can be constructed by cladding a metal so that the core metal pulls electrons within in order to create a positive charge on the outer surface of the mesh. In yet another exemplary embodiment, a radon detector can be constructed such that a small kit that is biased would allow collection of radon daughters and its subsequent transformation to a solid. The solid could then be detected with a detector or with a Geiger counter in the field. It will also be understood that when an element such as a layer, region or substrate is referred to as being “on” or “over” another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being “directly on” or “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements can 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. The present embodiments can include a design for an integrated circuit chip, which can be created in a graphical computer programming language, and stored in a computer storage medium (such as a disk, tape, physical hard drive, or virtual hard drive such as in a storage access network). It should also be understood that material compounds will be described in terms of listed elements, e.g., SiGe. These compounds include different proportions of the elements within the compound, e.g., SiGe includes SixGe1-x where x is less than or equal to 1, etc. In addition, other elements can be included in the compound and still function in accordance with the present embodiments. The compounds with additional elements will be referred to herein as alloys. Reference in the specification to “one embodiment” or “an embodiment” of the present invention, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment. It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This can be extended, as readily apparent by one of ordinary skill in this and related arts, for as many items listed. 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. Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like, can be used herein for ease of description to describe one element's or feature's relationship to another element(s) or feature(s) as illustrated in the FIGS. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the FIGS. For example, if the device in the FIGS. 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 term “below” can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein can be interpreted accordingly. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers can also be present. It will be understood that, although the terms first, second, etc. can 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 element. Thus, a first element discussed below could be termed a second element without departing from the scope of the present concept. Having described preferred embodiments of a system and method for collecting and removing radon from the atmosphere, the environment, and or one or more confined areas (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments described which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.
	description	This is a National Phase Application in the United States of International Patent Application No. PCT/JP2006/309502 filed May 11, 2006, which claims priority on Japanese Patent Application No. 139720/2005, filed May 12, 2005. The entire disclosures of the above patent applications are hereby incorporated by reference. 1. Field of the Invention The present invention relates to an X-ray switching and generating device which switches and generates X-rays for diagnosis and curing. 2. Description of the Related Art X-rays are electromagnetic waves having a wavelength of about 0.1 to 100 A (10−11 to 10−8 m). Among the ray, an X-ray having a short wavelength (10 to 100 keV, λ=1 to 0.1 A) is referred to as a hard X-ray, and an X-ray having a long wavelength (0.1 to 10 keV, λ=100 to 1 A) is referred to as a soft X-ray. Moreover, an X-ray emitted at a time when an electron beam or the like is struck on a substance and having a wavelength inherent in a constituting element of the substance is referred to as a particular X-ray. As apparatuses in which the X-rays are used, an X-ray transmission apparatus, an X-ray CT apparatus, an X-ray diffraction apparatus, an X-ray spectral apparatus and the like are utilized in broad fields such as a medical treatment, bioscience and material science. For example, to cure cardiac infarction, coronary angiography (IVCAG) in which an X-ray of about 50 keV is used is generally performed. Moreover, the X-ray CT apparatus is an apparatus in which an object to be measured is irradiated with X-rays from different directions to measure absorption of the rays, and an image is reconstructed by a computer to obtain a two-dimensional sectional image of the object. As generation sources of the X-rays, an X-ray tube and synchrotron radiation light are known. The X-ray tube is a device in which a thermion obtained by heating a filament in vacuum is accelerated at a high voltage, and is allowed to collide with a metal anode (target), thereby generating the X-ray. Examples of the X-ray to be generated from the X-ray tube include a continuous X-ray obtained by braking radiation of an electron, and a particular X-ray which is a bright line spectrum. The continuous X-ray is used as a light source for an application in which any X-ray having a specific wavelength is not required, for example, a transmission process for a medical treatment or industry. The particular X-ray is used for an application in which the X-ray having the specific wavelength is required, for example, X-ray diffraction, fluorescent X-ray spectroscopy or the like. On the other hand, the synchrotron radiation light (SR light) is an X-ray generated during an orbit change in a case where an orbit of the electron beam accelerated at a speed close to a light speed is changed by a strong magnet in an annular accelerator (a synchrotron). The SR light is an X-ray source (e.g., an X-ray intensity (a photon number): about 1014 photons/s, a pulse width: about 100 ps) which is incommensurably intense as compared with the X-ray tube, and the light is used for a field in which a high X-ray intensity is required. However, a synchrotron radiation light facility in which a synchrotron is used is a large-sized facility in which the synchrotron has a large diameter of about 50 m or more, and an orbit length reaches 100 m or more. Therefore, there is a problem that the facility even for a research or the medical treatment cannot easily be introduced. To solve the problem, a small-sized X-ray generation device is proposed in which a small-sized linear accelerator is used (e.g., Non-Patent Document 1). On the other hand, in a conventional X-ray CT apparatus, a monochromatic meter including two crystal plates is used as means for obtaining a monochromatic hard X-ray from the radiation light. Since the monochromatic X-ray CT apparatus has a low measurement precision of an electron density, a mixed two-color X-ray CT apparatus is proposed in which two types of X-rays having different mixture ratios of a dominant wave and a higher harmonic wave are used (e.g., Non-Patent Document 2). Moreover, Patent Document 1 has already been disclosed as a diagnosis and curing apparatus in which the particular X-ray is used as the X-ray for irradiation, and Patent Document 2 has already been disclosed as a diagnosis and curing apparatus in which the electron beam is used for curing and the X-ray is used for diagnosis. In “Small-Sized X-Ray Generation Device” of Non-Patent Document 1, as shown in FIG. 1, an electron beam 52 accelerated by a small-sized accelerator 51 (an X-band acceleration tube) is allowed to collide with laser 53 to generate an X-ray 54. The multi-bunch electron beam 52 generated by an RF electron gun 55 (a thermal RF gun) is accelerated by the X-band acceleration tube 51, and collides with the pulse laser light 53. The hard X-ray 54 having a time width of 10 ns is generated by Compton scattering. This device is miniaturized by using an X-band (11.424 GHz) corresponding to a frequency four times as high as that of an S-band (2.856 GHz) for general use in a linear accelerator as an RF for acceleration of the electron beam. For example, it is predicted that the hard X-ray having an X-ray intensity (the photon number) of about 1×109 photons/s and a pulse width of about 10 ps is generated. As shown in FIG. 2, “Mixed Two-Color X-Ray CT Apparatus” of Non-Patent Document 2 includes a rotary filter 61, a monochromatic meter 62, a collimator 63, a transmission type ion chamber 64, a scattering member 65, a sliding rotary table 66, an NaI detector 67 and a plastic scintillation counter 68. A dominant wave X-ray of 40 keV and a double higher harmonic wave X-ray of 80 keV are extracted from synchrotron radiation light 69a by the monochromatic meter 62, a mixture ratio of the 40 keV X-ray and 80 keV X-ray is regulated by the rotary filter 61, scattered X-ray spectrum from the scattering member 65 is observed by the NaI detector 67 to measure the mixture ratio, a size of a mixed two-color X-ray 69b is adjusted by the collimator 63, and the ray is transmitted through the transmission type ion chamber 64 and a subject 60. An intensity of the ray is measured by the plastic scintillation counter 68. According to this apparatus, the measurement precision of the electron density is improved. Moreover, the apparatus is successful in preparation of an image of the electron density and an effective atomic number. As shown in FIG. 3, “X-Ray Diagnosis Apparatus and X-Ray Curing Apparatus” of Patent Document 1 is an X-ray diagnosis apparatus in which an X-ray blocking metal complex taken by a person 77 being inspected is selectively accumulated in an affected part of the person, and the part is irradiated with an X-ray from X-ray generation devices 71, 72 to form an X-ray image of the affected part with an X-ray image pickup device 76. A metal target 73 to generate a particular X-ray which belongs to a predetermined energy region is used, and an electron beam generated by the electron generator 71 and accelerated by the electron accelerator 72 is struck on the metal target 73 to generate the particular X-ray. The ray is used as the X-ray for irradiation. It is to be noted that, in this drawing, reference numeral 74 is a filter device, and 75 is a bed. Moreover, “Radiotherapy Apparatus having Low Dose Low Order and Portal Imaging X-Ray Source” of Patent Document 2 is an apparatus which is applicable to both of megavolt radiotherapy and diagnosis X-ray source for portal imaging. As shown in FIG. 4, both of an electron beam 81 (a high-energy curing source) emitted from an electron gun (not shown) and accelerated in a waveguide and an X-ray 85 (a low-energy diagnosis source) generated by collision of an electron beam 83 emitted from an electron gun 82 with a movable target 84 are arranged along the physically same line 86 of the apparatus. The apparatus also includes an actuator which moves the movable target 84 in an axial direction. The beams are arranged at positions for curing or diagnosis, if desired. The electron beam 81 is used for the curing, and the X-ray 85 is used for the diagnosis. [Non-Patent Document 1] “Development of Small-Sized Hard X-Ray Source using X-band Liniac”, 2002, authored by Katsuhiro DOHASHI, et al. [Non-Patent Document 2] “Development of Mixed Two-Color X-Ray CT System” authored by Makoto SASAKI, et al., Medical Physics Vol. 23 Supplement No. 2 April 2003 [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-38475 titled “X-Ray Diagnosis Apparatus and X-Ray Curing Apparatus” [Patent Document 2] Japanese Patent Application Laid-Open No. 8-206103 titled “Radiotherapy Apparatus having Low Dose Low Order and Portal Imaging X-Ray Source” Since the “monochromatic hard X-ray” having a narrow band and high energy is used in the X-ray for diagnosis, a clear image can be obtained. Moreover, a patient does not have to be uselessly irradiated with radiation. Moreover, since a ray position of the X-ray for curing is disposed close to a light source of the X-ray for diagnosis, an error of an X-ray irradiation position can be reduced. Therefore, to perform the diagnosis and the curing with the same apparatus, there has been a strong demand for an X-ray switching and generation device in which the monochromatic hard X-ray as the X-ray for diagnosis and the particular X-ray as the X-ray for curing are switched and generated at the same light source position. In the diagnosis and curing apparatus of Patent Document 1, the particular X-ray which belongs to the predetermined energy region is used in both of the diagnosis and the curing. However, this particular X-ray has X-ray energy of 40 keV or more, and has a low absorption ratio with respect to a human body, but this ray is not monochromatic (i.e., has a broad band). Therefore, to obtain the clear image, a c-line blocking metal complex needs to be selectively accumulated of the affected part of the person being inspected. The ray has low energy and broad band even as the X-ray for curing. Therefore, the X-ray blocking metal complex needs to be accumulated in the affected part, and there has been a problem that a large burden is imposed on the person being inspected. Moreover, in the diagnosis and curing apparatus of Patent Document 2, the electron beam is used for the curing, and the X-ray is used for the diagnosis. However, the X-ray is used for diagnosis, the X-ray for curing is required. Therefore, the apparatus becomes complicated and expensive. To obtain the monochromatic hard X-ray from the radiation light, as disclosed in Non-Patent Document 2, the monochromatic meter including two crystal plates can be used. However, since the radiation light source is a large-sized facility, there is a problem that even for research or medical treatment the light cannot easily be introduced. Moreover, in a case where two types of X-rays are used in order to improve the precision of the X-ray image during the X-ray diagnosis and measure both of the distributions of the electron density and the effective atomic number, a crystal angle of the monochromatic meter needs to be precisely regulated. Therefore, it is very difficult to switch the rays at a high speed in a short time. Furthermore, in a case where the mixed two-color X-ray obtained by mixing the dominant wave X-ray and the double higher harmonic wave X-ray are mixed is extracted from the synchrotron radiation light as in Non-Patent Document 2, the wavelength of the X-ray is limited to that of the higher harmonic wave. There is also a problem that the dominant wave cannot be separated from the higher harmonic wave. The present invention has been developed in order to satisfy the above demands. That is, an object of the present invention is to provide a device for switching/generating X-rays for diagnosis and curing in which a monochromatic hard X-ray as the X-ray for diagnosis and a particular X-ray as the X-ray for diagnosis can be switched and generated in order to perform the diagnosis and the curing with the same apparatus. According to the present invention, there is provided a device for switching/generating X-rays for diagnosis and curing, comprising: an electron beam generation device which accelerates a pulse electron beam to transmit the beam through a predetermined rectilinear orbit; a laser generation device which generates a pulse laser light; a laser light introduction device which introduces the pulse laser light onto the rectilinear orbit so as to collide with the pulse electron beam; a metal target which generates a particular X-ray by collision with the pulse electron beam; and a target moving device which moves the metal target between a collision position on the rectilinear orbit and a retreat position out of the orbit, wherein at the collision position, a collision surface of the metal target is positioned spatially at the same position as a collision point between the pulse electron beam and the pulse laser light, the metal target is positioned at the retreat position, and the pulse electron beam collides head-on with the pulse laser light on the rectilinear orbit to generate a monochromatic hard X-ray for diagnosis, the metal target is positioned at the collision position, and the pulse electron beam collides with the metal target to generate the particular X-ray from the same collision point, and the X-rays for diagnosis and curing are emitted from the same light source position of the same apparatus. According to a preferable embodiment of the present invention, the metal target is made of tungsten, iron, cobalt, nickel, copper, molybdenum, silver or an alloy of these metals. Moreover, it is preferable to further comprise a collimator which is disposed between the collision point and a person being inspected and which controls radiating directions of the monochromatic hard X-ray for diagnosis and the particular X-ray for curing. Furthermore, the laser generation device includes a plurality of pulse laser units which generate a plurality of pulse laser beams having different wavelengths; a laser combining optical system which combines the plurality of pulse laser beams on the same optical path; and a laser control unit which controls the plurality of pulse laser units so that the plurality of pulse laser beams have a time difference therebetween. Moreover, it is preferable to further comprise a profile regulation optical system which regulates a beam profile of the pulse laser light at the collision point on the rectilinear orbit. According to a constitution of the present invention described above, when the metal target is disposed at the retreat position, the pulse electron beam collides head-on with the pulse laser light on the predetermined rectilinear orbit to generate the “monochromatic hard X-ray”. When the metal target is disposed at the collision position, the “particular X-ray” is generated from the same light source position by the collision of the pulse electron beam and the metal target. Therefore, when the target moving device simply moves the metal target to one of the “collision position” and the “retreat position”, the monochromatic hard X-ray as the X-ray for diagnosis and the particular X-ray as the X-ray for curing can be switched and generated in the same apparatus. In consequence, both of X-ray sources for diagnosis and curing can be generated from the same collision point (the light source position) by use of the same electron beam, complete agreement of the light source position of the image for diagnosis with that of the X-ray for curing can be realized, and an error of an X-ray irradiation position can be eliminated in principle. Moreover, in the present invention, since the pulse laser light collides head-on with the pulse electron beam on the rectilinear orbit to generate the monochromatic hard X-ray, collision efficiency can be maximized. Furthermore, the wavelength of the X-ray generated by the collision of the pulse electron beam with the pulse laser light is determined depending on that of the laser light. Therefore, when the plurality of pulse laser beams having different wavelengths are generated by the laser generation device, two or more types of monochromatic hard X-rays can successively be switched and generated at a short time interval. For example, when the laser beams having the plurality of types of wavelengths are alternately emitted and are allowed to collide with the electron beam during the collision of the electron beam with the laser light, two-color X-rays can alternately be generated. An electron density distribution and an element distribution can be obtained with high precision, and a sophisticated curing plan can be made. Furthermore, the present invention is applicable to the curing combined with a drug delivery system by use of this hard X-ray. Preferable embodiments of the present invention will hereinafter be described with reference to the drawings. It is to be noted that, in the drawings, a common part is denoted with the same reference numeral, and redundant description is omitted. FIG. 5 is the whole constitution diagram of a diagnosis and curing apparatus including a device for switching/generating X-rays for diagnosis and curing according to the present invention. In the drawing, reference numeral 6 is a person being inspected, 7 is a movable bed on which the person being inspected is laid, 8 is a main body of the diagnosis and curing apparatus, and 9 is a movable arm including an X-ray detector 9a. The device for switching/generating the X-rays for diagnosis and curing according to the present invention is incorporated in the main body 8. In the device, a monochromatic hard X-ray 4 as the X-ray for diagnosis and a particular X-ray 5 as the X-ray for curing are switched and generated to irradiate the person 6 being inspected. The monochromatic hard X-ray 4 is a narrow-band X-ray of preferably about 10 to 40 keV, so that any X-ray blocking metal complex does not have to be accumulated in an affected part of the person and burdens to be imposed on the person can be reduced. The X-ray can be used in detecting absorption of the ray as a light source of X-ray CT by the X-ray detector 9a and reconstructing an image by a computer to obtain a two-dimensional sectional image of the person 6. Moreover, it is preferable that the particular X-ray 5 is a high-energy X-ray of, for example, about 5 to 50 MeV which has little influence on a normal tissue in front of the affected part. FIG. 6 is a plan view showing a first embodiment of the device for switching/generating the X-rays for diagnosis and curing according to the present invention. As shown in this drawing, a multicolor X-ray generation device of the present invention includes an electron beam generation device 10, a composite laser generation device 20, a laser light introduction device 30 and a target moving device 40. The electron beam generation device 10 has a function of accelerating an electron beam to generate a pulse electron beam 1, and transmitting the beam through a predetermined rectilinear orbit 2. In this example, the electron beam generation device 10 includes an RF electron gun 11, an α-magnet 12, an acceleration tube 13, a pending magnet 14, Q-magnets 15, a deceleration tube 16 and a beam dump 17. The RF electron gun 11 and the acceleration tube 13 are driven by a high-frequency power source 18 of an X-band (11.424 GHz). An orbit of the electron beam drawn from the RF electron gun 11 is changed by the α-magnet 12. The beam then enters acceleration tube 13. The acceleration tube 13 is a small-sized X-band acceleration tube which accelerates the electron beam to generate a high-energy electron beam of preferably about 50 MeV. This electron beam is the multi-bunch pulse electron beam 1 of, for example, about 1 μs. The pending magnet 14 bends the orbit of the pulse electron beam 1 with a magnetic field, transmits the beam through the predetermined rectilinear orbit 2, and guides the transmitted pulse electron beam 1 to the beam dump 17. A convergence degree of the pulse electron beam 1 is regulated by the Q-magnets 15. The pulse electron beam 1 is decelerated by the deceleration tube 16. The beam dump 17 traps the pulse electron beam 1 transmitted through the predetermined rectilinear orbit 2 to prevent leakage of radiation. A synchronization device 19 executes control so that the electron beam generation device 10 is synchronized with the composite laser generation device 20, a timing of the pulse electron beam 1 is collided with that of the pulse laser light 3 described later and the pulse electron beam 1 collides with pulse laser light 3 at a collision point 2a (a light source position) on the predetermined rectilinear orbit 2. By the electron beam generation device 10 described above, the multi-bunch pulse electron beam 1 of, for example, about 50 MeV, about 1 μs can be generated and transmitted through the predetermined rectilinear orbit 2. The laser generation device 20 has a function of generating the pulse laser light 3. In this example, the laser generation device 20 has a pulse laser unit 22, a laser combining optical system 23, a laser control unit 24 and a laser dump 25. The pulse laser unit 22 generates the pulse laser light 3 having a specific wavelength. For example, as the pulse laser unit 22, Nd-YAG laser having a wavelength of 1064 nm is used. In this example, the laser combining optical system 23 includes a total reflection mirror 23a. The total reflection mirror 23a reflects the pulse laser light 3 of the pulse laser unit 22 toward a first mirror 32 of the laser light introduction device 30. According to this constitution, the pulse laser light 3 can be reflected on the first mirror 32 and introduced onto the predetermined rectilinear orbit 2 of the pulse electron beam 1. The laser control unit 24 controls the pulse laser unit 22. For example, when the pulse laser light 3 has a pulse oscillation number of 10 pps and a pulse width of 10 ns, the laser control unit performs the control so that the pulse electron beam 1 collides with the pulse laser light 3 at the collision position 2a of the predetermined rectilinear orbit 2 in response to a command from the synchronization device 19. The laser dump 25 traps the pulse laser light 3 transmitted through the rectilinear orbit 2 and then returned to the laser generation device 20 via a second mirror 34 to prevent the light from scattering. In FIG. 6, the X-ray generation device of the present invention further has a profile regulation optical system 26 between the first mirror 32 and the total reflection mirror 23a. This profile regulation optical system 26 is, for example, a composite lens, and regulates a beam profile (e.g., a size, a tilt and a position) of the pulse laser light 3 at the collision position 2a of the rectilinear orbit 2. In this example, the laser light introduction device 30 has two mirrors 32, 34. A plurality of pulse laser beams 3 are introduced along the rectilinear orbit 2 so as to collide with the pulse electron beam 1 by the first mirror 32, and the pulse laser light 3 transmitted through the rectilinear orbit 2 is returned to the laser dump 25 of the laser generation device 20 by the second mirror 34. The first mirror 32 and the second mirror 34 may be total reflection mirrors. According to the above-mentioned constitution, a wavelength of the X-ray generated by the collision of the pulse electron beam 1 with the pulse laser light 3 is determined depending on a wavelength of the pulse laser light 3. The monochromatic hard X-ray 4 can be generated by use of, for example, Nd-YAG laser having a wavelength of 1064 nm. Moreover, the pulse laser light 3 collides head-on with the pulse electron beam 1 along the rectilinear orbit 2 to generate the monochromatic hard X-ray. Therefore, collision efficiency can be maximized. It is to be noted that the pulse laser unit and the pulse laser light are not limited to this example, and ArF (wavelength of 193 nm), KrF (wavelength of 248 nm), XeCl (wavelength of 308 nm), XeF (wavelength of 351 nm) or Fe (wavelength of 157 nm) of excimer laser, a second higher harmonic wave (wavelength of 532 nm), a third higher harmonic wave (wavelength of 355 nm), a fourth higher harmonic wave (wavelength of 266 nm) or a fifth higher harmonic wave (wavelength of 213 nm) of YAG laser or the like may be used. The target moving device 40 is an actuator which moves a metal target 42 between a collision position on the rectilinear orbit 2 and a retreat position out of the orbit. This actuator may be a translatory liquid pressure cylinder or a translatory electromotive cylinder. It is to be noted that the target moving device 40 may be constituted so as to be manually operated in a case where a frequency of switching is small. Efficiency of conversion of the pulse electron beam 1 which has collided with the metal target 42 is proportional to an atomic number of the target and an acceleration voltage of the electron beam. Therefore, to increase the conversion efficiency, as the target, a substance having a large atomic number, for example, tungsten, iron, cobalt, nickel, copper, molybdenum, silver or an alloy of these metals may be used. Moreover, the collision position of the metal target 42 is set so that a collision surface of the metal target 42 is positioned spatially at the same position as that of the collision point 2a between the pulse electron beam 1 and the pulse laser light 3. This collision surface may be constituted so that the X-rays are generated in an irradiating direction of the X-rays (a downward direction in FIG. 5, a direction crossing a sheet surface of FIG. 6 at right angles). According to the above constitution, the metal target 42 is positioned at the retreat position, and the pulse electron beam 1 is allowed to collide head-on with the pulse laser light 3 on the rectilinear orbit 2 to generate the monochromatic hard X-ray 4 from the collision point 2a. Moreover, the metal target 42 is positioned at the collision position on the rectilinear orbit 2, and the particular X-ray 5 is generated from the same collision point 2a by the collision of the metal target 42 with the pulse electron beam 1. Furthermore, when the acceleration voltage of the pulse electron beam 1 and a material of the metal target 42 are appropriately selected, the generated particular X-ray 5 can be regulated into the high-energy X-ray of about 5 to 50 MeV which has little influence on a normal tissue in front of the affected part of the person. The monochromatic hard X-ray 4 and the particular X-ray 5 generated at the collision point 2a have little directivity, and are radiated from every direction. Therefore, as shown in FIG. 5, a collimator 44 may be disposed between the collision point 2a and the person 6 to control radiating directions of the monochromatic hard X-ray 4 and the particular X-ray 5. FIG. 7 is a diagram of a second embodiment of a device for switching/generating X-rays for diagnosis and curing according to the present invention. In this example, a laser generation device 20 has a plurality of pulse laser units 22A, 22B, a laser combining optical system 23, a laser control unit 24 and a laser dump 25. The plurality of pulse laser units 22A, 22B generate a plurality of pulse laser beams 3a, 3b having different wavelengths. For example, as the pulse laser units 22A, 22B, Nd-YAG laser having a wavelength of 1064 nm and Nd-YAG laser obtained by incorporating KTP crystals in this Nd-YAG laser and having a wavelength of 532 nm are used. The wavelength is converted into a half wavelength by the crystals. In this example, the laser combining optical system 23 includes a total reflection mirror 23a and a half mirror 23b. The total reflection mirror 23a reflects pulse laser light 3a of the pulse laser unit 22A toward a first mirror 32 of a laser light introduction device 30. The half mirror 23b is a half mirror through which the pulse laser light 3a can pass as it is, and the pulse laser light 3b is reflected toward the first mirror 32 of the laser light introduction device 30. According to this constitution, the plurality of pulse laser beams 3a, 3b are combined on the same optical path, and are allowed to enter the first mirror 32 as pulse laser light 3. The plurality of combined pulse laser beams can be introduced onto a rectilinear orbit 2. The laser control unit 24 controls the plurality of pulse laser units 22A, 22B so that the plurality of pulse laser beams 3a, 3b have a time difference therebetween. For example, each of the plurality of pulse laser beams 3a, 3b has a pulse oscillation number of 10 pps, and a pulse width of 10 ns. In this case, when one pulse oscillation time is shifted, the plurality of pulse laser beams 3a, 3b (wavelengths of 1064 nm and 532 nm) each having a pulse width of 10 ns are alternately output, and can be struck on the first mirror 32 as the pulse laser light 3. Another constitution is similar to that of the first embodiment. It is to be noted that the number of the pulse laser units is not limited to two, and three or more units may be used. The pulse laser light is not limited to the above-mentioned examples, and ArF (wavelength of 193 nm), KrF (wavelength of 248 nm), XeCl (wavelength of 308 nm), XeF (wavelength of 351 nm) or F2 (wavelength of 157 nm) of excimer laser, a third higher harmonic wave (wavelength of 355 nm), a fourth higher harmonic wave (wavelength of 266 nm) or a fifth higher harmonic wave (wavelength of 213 nm) of YAG laser or the like may be used. According to the constitution of the present embodiment, in the same manner as in the first embodiment, a metal target 42 can be positioned at a retreat position, and a pulse electron beam 1 can be allowed to collide head-on with the pulse laser light 3 on the rectilinear orbit 2 to generate a monochromatic hard X-ray. The metal target 42 may be positioned at a collision position on the rectilinear orbit 2 to allow the pulse electron beam 1 to collide with the metal target 42, and a particular X-ray 5 can be generated from the same collision point 2a. Moreover, a wavelength of the X-ray generated by the collision of the pulse electron beam 1 with the pulse laser light 3 is determined depending on that of the pulse laser light 3. Therefore, when the plurality of pulse laser beams 3a, 3b having different wavelengths are generated by the composite laser generation device 20 according to this second embodiment, two or more types of monochromatic hard X-rays 4 (4a, 4b) can successively be switched and generated at a short time interval. That is, the laser generation device can generate the pulse laser light in a short period (e.g., 10 pps or more). Therefore, when the laser control unit controls the plurality of pulse laser beams so as to make a time difference between the beams, the plurality of pulse laser beams are successively allowed to collide head-on with the pulse electron beam in a short period, and two or more types of plurality of monochromatic hard X-rays can successively be switched and generated in a short period (e.g., 10 pps or more). Radiating directions of the monochromatic hard X-rays 4 (4a, 4b) and the particular X-ray 5 generated at the collision point 2a are controlled by the collimator 44, and the rays are radiated from the collision point 2a toward a person 6 as shown in FIG. 5. The plurality of taken monochromatic hard X-rays 4 (4a, 4b) can be used in angiography and two-color X-ray CT, and the particular X-ray 5 can be used in curing the person 6. Therefore, according to the second embodiment, the wavelengths of the X-rays can successively be switched at a high speed without physically moving the devices or components, a change of a subject with a wavelength switch time can be reduced, resolution of an X-ray image is improved, an electron density distribution and an element distribution can be obtained highly precisely, and a curing schedule can be sophisticated. It is to be noted that the present invention is not limited to the above-mentioned embodiments. Needless to say, the present invention can variously be modified without departing from the scope of the present invention.
	summary
	claims	1. A device for storing radioactive material, comprising a radioactive material container including a lower cup portion, an upper cup portion which is securely engaged to the lower cup portion, and a chamber with a cushion member mounted in a top and a bottom end thereof, which is formed inside the container for storing radioactive material; and a radioactive material container outer shield including a base portion and a lid which is securely covered on the base portion, the base portion further including a room to accommodate the radioactive material container wherein the said radioactive material container comprises a ring member pivotedly connected to a top end and rested between the lid and the upper cup portion, wherein when the lid is opened, the ring member will stand out of the base portion, further comprising a buckle member pivotedly mounted on an outer surface of the open end of the base portion, the lid pivotedly mounted to the base portion opposite to the buckle member, and an O-ring provide between the base portion and the lid, wherein the lid further includes a resilient snap to snap on the buckle member after the lid is buckled by the buckle member. 2. The device of claim 1 , wherein the lower cup portion, the upper cup portion, the base portion and the lid are made of radiation-resistant material. claim 1 3. The device of claim 2 , wherein the radiation-resistant material includes lead. claim 2 4. The device of claim 2 , wherein the radiation-resistant material includes tungsten. claim 2 5. The device of claim 1 , wherein a roughened surface is formed on an outer surface of the lower or the upper cup portions. claim 1 6. The device of claim 4 , wherein the roughened surface is made of polymer. claim 4 7. The device of claim 1 , wherein the upper cup portion includes a threads configured to engage the threads of a threaded area of the lower cup portion, and an O-ring fits between the lower and the upper cup portions. claim 1 8. The device of claim 1 , wherein the chamber is syringe-like. claim 1 9. The device of claim 8 , wherein the chamber is formed by combining an upper and a lower internal cavities of the upper and the lower cup portions, respectively. claim 8 10. The device of claim 1 , wherein the cushion member is a sponge. claim 1 11. The device of claim 1 , further comprising a magnetic member mounted on a bottom surface of the lid while the ring member is made by material capable of being attracted by the magnetic member, such that when the lid is opened, the ring member is attracted by the magnetic member to stand out of the base portion. claim 1 12. The device of claim 1 , further comprising an elastic member furnished between the upper cup portion and the ring member such that when the lid is opened, the ring member is raised by the elastic member. claim 1 13. The device of claim 1 , further comprising a tool for moving out the radioactive material container from the outer shield. claim 1 14. The device of claim 13 , wherein the tool is a container hook. claim 13 15. The device of claim 1 , further comprising a shipping apparatus for transportation of a radioactive material storing device, the shipping apparatus comprising: claim 1 a body bag including a protective foam surrounding a hollow space for holding the storing device inside the body bag; a retractable handle extended upwardly from the bag body; and a plurality of wheels mounted under the bag body. 16. The device of claim 15 , wherein the protective foam is made of polymer. claim 15 17. The device of claim 1 , further comprising a shipping apparatus for transportation of a radioactive material storing device, the shipping apparatus comprising: claim 1 a body bag including a protective foam surrounding a hollow space for holding the storing device inside the body bag; and two handles fixedly furnished on the bag body. 18. The device of claim 17 , wherein the protective foam is made of polymer. claim 17
043893686	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, there is shown a nuclear reactor 10 including a nuclear reactor pressure vessel 20 surrounded by biological shielding 34 and having an active core or fuel region 24 therein. Core 24 is supported in the reactor pressure vessel 20 in a well-known manner by core support barrel 22 (not shown). The reactor coolant is circulated through the cold leg 16 by the reactor coolant pump 14. As best seen in FIG. 2, the cold coolant enters the reactor pressure vessel 20 and impinges upon the core support barrel 22. The flow of the coolant is then deflected downwardly to pass through the annular region 21 between the core support barrel 22 and the reactor pressure vessel 20 to the lower portions of the reactor pressure vessel where it is deflected upwardly to pass to the interior of the reactor core support barrel. Once on the interior of the reactor core support barrel, the coolant flows upwardly through the fuel assemblies (not shown) of the reactor core 24 and subsequently passes into the reactor plenum 25 immediately above the reactor core 24. From here the coolant is again deflected to pass out of the reactor pressure vessel 20 and into hot leg 18 by which means it is delivered to steam generator 12. During its passage through the steam generator 12, the coolant is cooled in a well-known manner by transferring its heat content to the secondary coolant system. After being cooled in the steam generator 12, the primary coolant is recirculated by the reactor coolant pump 14 and the cycle is repeated. Also shown in FIGS. 1 and 2 is a portion of the emergency core cooling system which includes storage tank 28, check valve 36 and delivery pipe 26. Storage tank 28 contains a large quantity of highly borated water. Check valve 36 is designed to permit the passage of the borated water contained in tank 28 to the primary coolant system by means of pipe 26 when the pressure in the primary coolant system drops below a predetermined pressure. Such a pressure drop occurs with a loss of coolant accident or LOCA. The borated water is then injected into the primary coolant system at penetration 27 in the cold leg 16. The borated emergency coolant is injected under a high pressure so that the coolant is caused to flow through the cold leg 16 into the reactor vessel 20, and down through the annulus 21 between the reactor vessel 20 and the core support barrel 22 to reflood the reactor core 24 from the bottom. As best shown in FIG. 2, a coolant pump 14 comprises a pump impeller 40 mounted by means of a shaft 41 in a pump housing 42 which is interposed in the cold leg 16 of the reactor system. The pump shaft 41 is mechanically coupled to the drive shaft 45 of an electric motor 46. In the prior art the coupling between the pump shaft 41 and the drive shaft 45 comprised a pair of plates or flanges each rigidly fixed to a different one of the shafts 41 and 45. The flanges were then bolted together in order to provide a rigid mechanical coupling between the shafts 41 and 45 and yet allow the shafts to be disconnected so that the pump housing 42 could be removed from the system to allow repair of the impeller 40 and pump seals on the impeller shaft 41 as necessary. Also, in the prior art, the motor 46 was provided with a fly-wheel represented generally at 48 to maintain rotation of the motor 46 and pump impeller 40 in the event of a power failure. According to this invention, the mechanical coupling between the pump shaft 41 and the drive shaft 45 is provided by a unidirectional drive means adapted to enable the pump impeller 40 to rotate at a higher rotational speed than the rotational speed of the motor 46 in the pumping direction only. One preferred embodiment of the unidirectional drive means according to this invention is shown in FIGS. 3 and 4 with rotation in the clockwise direction corresponding to the pumping direction. Referring to FIG. 3, a ratchet block 50 is rigidly fixed to the free end of the pump shaft 41. According to this embodiment of the invention, a pair of semicircular cam surfaces 51 are provided on the surface of the cam block 50 facing the drive shaft 45. Each of the cam surfaces 51 terminates in an abutment surface or ratchet tooth 52. Similarly, according to this embodiment of the invention, one or more ratchet arms 54 are mounted on a mounting block 55 by pivot means 56 at one end of the arm 54. The mounting block 55 is rigidly fixed to the free end of the drive shaft 45. The free end of each ratchet arm 54 is provided with an abutment surface 58 adapted to engage the abutment surface or ratchet tooth 52 of the ratchet block 50. In operation, the ratchet block 50 and mounting block 55 as shown in FIG. 3, would be brought into close spaced relationship to each other with the axes of the pump shaft 41 and the drive shaft 45 in coaxial alignment. Relative rotational movement of the drive shaft 45 about its axis in a clockwise direction with respect to the drive shaft 41 would force the surfaces 58 at the free ends of the ratchet arms 54 into abutment with the ratchet teeth 52 of the ratchet block 50 causing the pump shaft 41 to rotate in a clockwise direction with the drive shaft 45. If the drive shaft 45 should cease to rotate in a clockwise direction, the pump shaft 41 can freely continue to rotate in a clockwise direction with the cam arms 54 riding on the cam surfaces 51 and ratcheting over the ratchet teeth 52. Similarly, the pump shaft 41 may rotate in a clockwise direction at a higher rotational rate than the rate of clockwise rotation of the drive shaft 45. However, the pump shaft 41 cannot rotate in a counterclockwise direction with respect to the drive shaft 45. In the event of a loss of coolant accident or LOCA, due to a leak in the cold leg of the system between the pump 14 and the reactor pressure vessel, a high rate of flow of fluid through the pump housing 42 will occur tending to drive the impeller 40 of the pump 14 at a very high rate of speed. According to the teaching of this invention, the impeller 40 of the pump 14 will be permitted to free-wheel with respect to the motor 46 and flywheel 48. Thus, there will be no tendency to drive the motor 46 and flywheel 48 at an excessive rotational speed and yet the flow of fluid through the system will not be impeded. Furthermore, the flow of fluid in the normal direction proper for facilitating the introduction of borated water under emergency conditions will be enhanced. It is believed that those skilled in the art will make obvious modifications in the specific embodiment of this invention as shown in the drawing without departing from the scope of the following claims. Any number of ratchet teeth and ratchet arms may be used. Spring-loaded ratchet teeth or ratcheting means of any type capable of handling the forces involved can be used. Furthermore, other unidirectional drive means such as unidirectional bendix or unidirectional fluid drives may be used, although neither would be as efficient as the preferred ratchet drive. In addition, a unidirectional fluid drive would not be as effective as the preferred ratchet drive in enhancing the flow of fluid in the normal direction under emergency conditions.
051503921	description	DESCRIPTION OF A PREFERRED EMBODIMENT X-ray lithography is an important technology for the manufacture of deep submicron integrated circuits. The implementation of this technology is proximity printing, where an 1:1 X-ray mask is positioned 10 to 40 .mu.m above the surface of the wafer. The mask and wafer are then exposed with a broad beam of X-rays, leaving an image of the mask in a radiation-sensitive film on the surface of the wafer. Such a process requires an alignment accuracy between the mask and wafer of a few tens of nanometers in order that multiple lithography levels precisely register. In addition, it requires careful control of the gap between the mask and the wafer because too large a gap will degrade the image due to diffraction effects and penumbral blurring, and too small of a gap increases the change of accidental touching and subsequent damage to the very delicate mask and/or wafer. In the prior art, alignment is achieved by shining light through the mask, which is usually made on a very thin, semitransparent membrane. The wafer is adjusted relative to the mask until corresponding marks on the mask and wafer properly coincide. However, due to limitations arising from the wavelength of visible light, it is difficult to achieve the required accuracy. Gap control is achieved by precise mechanical fixturing of the mask and wafer, which is difficult to control better than several micrometers; currently a gap of 40 .mu.m is typically used. The scanning tunneling microscope and the atomic force microscope are two closely related instruments that are both capable of achieving atomic resolution in the X, Y and Z dimensions. In the present invention, combinations of elements of these microscopes with X-ray masks are effectively used for mask to wafer alignment. The atomic force microscope is disclosed in U.S. Pat. No. Re.33,387 and the scanning tunneling microscope is disclosed in U.S. Pat. No. 4,343,993, both of which are cited in the Prior Art section herein. The atomic force microscope also described by G. Binning, C. F. Quate and Ch. Gerber, Phys. Rev. Letters, Vol. 56, No. 9, March 1986, pp. 930-933, employs a sharply pointed tip attached to a spring-like cantilever beam to scan the profile of a surface to be investigated. At the distances involved, attractive or repulsive forces occur between the atoms at the apex of the tip and those at the surface, resulting in tinyl deflections of the cantilever beam. This deflection is measured by means of a tunneling microscope, i.e., an electrically conductive tunnel tip is placed within tunnel distance from the back of the cantilever beam, and the variations of the tunneling current are used to measure the deflection. With known characteristics of the cantilever beam, the forces occurring between the AFM tip and the surface under investigation can be determined. The present invention proposes an atomic force microscope or scanning tunneling microscope comprising a pointed tip provided for interaction with a wafer and means for approaching said tip to said surface to within a distance on the order of one tenth of a nanometer, and for scanning said tip across said surface in a matrix fashion. This atomic force microscope is characterized in that said tip is attached to one surface of an oscillating body carrying, on opposite sides thereof, a pair of electrodes permitting an electrical potential to be applied, that, in operation and with said tip remote from said surface, said body is excited to oscillate at its resonance frequency, and that, with said tip maintained at said working distance from said surface, said body oscillates at a frequency deviating in a characteristic manner from said resonance frequency, that said deviation is compared with a reference signal, and that the resulting differential signal is passed through a feedback loop to control said means for approaching the tip to said surface. The basic concept of a scanning tunneling microscope is to place a very sharp, conducting tip having tip dimensions on the order of the size of 1 atom in diameter close to a conductive surface. If the tip is brought very close to a conductive surface, i.e., within the space of the diameters of several atoms, (approximately within 5 angstroms), a tunneling current flows between the tip and the surface. That is, the probability density function of electrons for atoms in the tip overlaps in space the probability density function of electrons for atoms on the surface. As a result, tunneling occurs in the form of electron current flow between the tip and the surface if a suitable bias voltage between these two conductors is applied. The feature of the present invention is that the capabilities of the atomic force microscope are used for X-ray mask gap control and alignment by making the cantilever element as an integral part of the X-ray mask being controlled and aligned. One or more apertures are formed in the mask, in the form of U-shaped slots, leaving a portion of the mask material which functions as the cantilever element. The operation of the cantilever element formed from the X-ray mask is in accordance with standard atomic force microscope or scanning tunneling microscope techniques as described in the prior art. Referring to FIG. 1, a cross section of a perspective view of a wafer 10 and an X-ray mask substrate 11 with membrane 12 which contains a pattern to be transferred to the wafer 10 is illustrated in schematic form wherein a cantilever 14 and tip 16 portion such as used on an atomic force or scanning tunneling microscope are fabricated directly as part of the mask 11. The vertical (z) motion of the tip 16 with respect to the wafer 10 is achieved with a piezoelectric device 18 which is mounted on a movable support 22. Such a device could be a tube having an electrode divided into quadrants so that the end of the tube 20 could be positioned in three dimensions to allow for alignment of the end of the tube to the cantilever tip 16. X and Y motion of the tip 16 and the mask membrane 12 relative to the wafer 10 could be achieved by mounting the wafer 10 on an x-y stage driven by piezoelectric or other transducers. Moving wafers in lithography systems in the x, y and z directions in response to control signals is a technique well known to those skilled in the art. U.S. Pat. Nos. 4,560,880 and 4,870,668 discussed in the description of the prior art teach such systems. Thus, in FIG. 1, means 30 for translating device 18 in the x, y and z dimensions and means 32 for translating wafer 10 in the x, y and z dimensions are illustrated in very schematic form. Fabricating the cantilever element 16 requires only one or two additional processing steps since membrane technology is already used to fabricate the mask. Thus it is possible to fabricate the entire instrument directly onto the mask substrate 11 using multiple lithographic steps and piezoelectric thin film technology. The wafer 10 includes an alignment mark 24 as illustrated in FIG. 1. In operation, the wafer 10, mask membrane 12, and z piezoelectric tube 18 are held rigidly but adjustably with respect to each other by a mechanical fixture (not shown). The z piezoelectric tube 18 is lowered until tip 20 touches cantilever 14; it is then lowered further by the designed gap spacing, deflecting the cantilever 14 downward. The wafer 10 is then raised until it is detected by the tip 16 on the cantilever 14, either by sensing a tunneling current (STM) or a force (ATM). The wafer 10 is now at the correct z gap setting, and is scanned back and forth in the x and y directions until the location of the alignment mark 24 is determined by the cantilever tip 16 following the contours of the alignment mark 24, thus setting the proper alignment between the wafer and the mask in the x, y direction. The wafer 10 is first exposed by a mask which has alignment marks in place of the cantilevers. The pattern is transferred as a relief on the wafer surface for subsequent mark detection. The remaining masks would have three cantilevers located around the edge of the exposure field in order to align the wafer in all six degrees of freedom, as shown in FIG. 2. Spare cantilever locations could be provided in case any were damaged or broken. Deviations of the ends of the cantilevers from their design locations could be mapped out by measuring the alignment accuracy of test exposures.

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