Abstract: A method and apparatus for withdrawing spent fuel rods from a nuclear fuel rod assembly into a different nuclear fuel rod container wherein the spent fuel rods have a higher fuel rod density, whereby a greater number of spent fuel rods can be stored in a water-storage pool. The individual rods are moved from a fuel assembly and through a transition funnel by movable grippers at opposite ends of the funnel. One movable gripper reciprocates between gripping and release positions in a gap between the fuel assembly and the transition funnel. A stationary gripper can be located in the gap at the entry side of the funnel to hold the fuel rods while the movable gripper returns from a release position to the gripping position. Both grippers include members which can be pressed into frictional engagement with the spaced apart array of fuel rods. All of the fuel rods are withdrawn concurrently and are merged toward one another into a tighter array within the transition funnel and emerge as a bundle.

Abstract: A grid assembly fixture for use in assembling grid straps to form a grid comprises a generally flat plate having first and second sets of parallel grooves, with the grooves of the sets at right angles. A retention strap comprises first and second pairs of bars, the bars of each pair hinged together adjacent their ends, and releasable joining elements for joining the pair of bars.A method of assembling the grid straps includes positioning a first set of straps in a grid assembly fixture, positioning a second set of straps at right angles to the first set to form a grid, placing outer straps on the grid, and placing a retention strap on the outer straps.

Abstract: An improved arrangement for attaching and reattaching a top nozzle of a reconstitutable fuel assembly includes a sleeve member associated with each guide thimble of the fuel assembly and complementary elements for attaching the sleeve member and the upper end portion of the guide thimble together. The sleeve member includes an inner tubular alignment sleeve portion which receives the guide thimble upper end portion and extends between the upper hold-down and lower adapter plates of the top nozzle. The sleeve member also includes an outer tubular shroud portion having a lower annular flange which underlies a coil spring surrounding the sleeve portion and interconnects the shroud portion and the sleeve portion. The outer shroud portion extends upwardly about a portion of the coil spring for protecting the spring from damage by coolant cross flow from adjacent fuel assemblies.

Abstract: A method and apparatus for withdrawing spent fuel rods from a nuclear fuel rod assembly into a different nuclear fuel rod container wherein the spent fuel rods have a higher fuel rod density, whereby a greater number of spent fuel rods can be stored in a water storage pool. The individual rods are drawn upwardly through a transition funnel from the fuel rod assembly into a fuel rod container. Individual wires extend through the fuel rod container, through the transition funnel and are secured to the top ends of the individual fuel rods within a fuel rod assembly. All of the fuel rods are withdrawn concurrently and are merged toward one another into a tighter array within the fuel rod container.

Abstract: An apparatus for transportation, positioning and sealing a container used for receiving irradiated fuel from beneath a loading and unloading pit of a nuclear installation including a cart which is successively brought through a hall underneath a loading preparation station, underneath a removal station for removing the plug from the container, and underneath a penetration shaft providing the connection between the loading and unloading pit and the hall where the cart travels. The cart includes a framework placed on a rolling platform with a sliding and rolling support therebetween, and guided between side rails on the walls of the hall.

Abstract: The invention provides for a procedure for permanently storing radioactive material in a rock chamber, comprising an enclosed construction (4) completely separated from the walls, floor and ceiling of the rock, made of permanent material impervious to water, in which materials in encapsulated (9) form are stored, and the outer spacing between the walls, ceiling and floor of the rock and the construction is completely filled with material not impervious to water (5). In the invention, the encapsulated material is placed inside the construction by means of a robot (10) on both sides of a track provided for the robot. When the construction is totally or partially filled with material, the construction or part of it containing material is sealed with bentonite or similar, leaving a passage (13) for the robot in the construction, which passage is filled with water-displacing material that is easy to dig.

Abstract: A manufacturing installation having several fixed work stations and a handling device, said work stations being disposed along at least one handling bay. It further comprises a handling device having, on the one hand, an overhead transporter movable along the handling bay and having means for grasping, transporting and setting down a batch of a given number of objects and, on the other hand, at right angles to each work station, an intermediate take up and storage device having an upstream station for setting down by the transporter, a downstream station for taking up by the transporter and a conveyor capable of grasping the batch of objects as a whole at the upstream station, presenting the objects one by one at the work station and placing them as a whole in the downstream station, so as to completely decouple the operation of the transporter from each work station.

Abstract: An integral reusable locking arrangement for a top nozzle of a reconstitutable fuel assembly includes a thin-walled tubular section on the upper end portion of each guide thimble of the fuel assembly above an externally threaded section thereon and an axial section on ecah alignment sleeve of the top nozzle above its lower internally threaded section. The tubular section has an annular circumferential protrusion defined thereon having an external diametric size which is greater than that of the remainder of the tubular section. The axial section on the sleeve has an internal diametric size which is greater than that of the tubular section but less than that of the protrusion.

Abstract: A system constructed of three tools for manipulating fuel rods with a nuclear fuel assembly is disclosed. The individual tools are adapted for displacing fuel rods upwardly and downwardly along their longitudinal axes and for rotating same 360.degree. without having to remove the fuel rods from their location within a nuclear fuel assembly. The individual tools are operative on-site from a remote location while the nuclear fuel assembly is maintained underwater in a spent fuel pool. By manipulating the fuel rods, those areas previously hidden from visual inspection such as within grids may be inspected for defects and the like.

Abstract: A fixture for rectifying one of several different types of repairable and irreparable damage to the upper end portions, or insert sleeves, of the guide thimbles of a fuel assembly held in a work station includes a base having a plurality of tool positioning openings defined therein in a pattern matched with that of the guide thimbles and several aligning holes for mounting the base on guide members of the work station such that the tool positioning openings are disposed in alignment with the guide thimbles. Also, a plurality of different tools are selectively mountable in the openings of the base. Each tool is adapted to operate to rectify a different one of the types of repairable and irreparable damage to the insert sleeves of the guide thimbles.

Abstract: A liquid metal cooled fast breeder reactor which permits a closer installation of a fuel handling mechanism relative to an upper reactor core structure of the reactor. The fuel handling mechanism has a fuel handling body without a housing, and has a rotational driving device on a rotating plug of a shield plug device of a reactor vessel. The fuel handling mechanism has an aseismatic support extending outwardly from the upper reactor core structure. The fuel handling mechanism is supported, at its upper portion, by the rotational driving device, and secured, at its lower protion, by the aseismatic support.

Abstract: A tool (78) for grasping a multiplicity of nuclear fuel rods (42) to remove them from a nuclear fuel assembly (32) and relocate them, preferably, into a fuel consolidation device (86). The tool has a gripper head (200) reciprocably guided within a shroud (80). A distinct jaw mechanism (216) for grasping each of the multiplicity of fuel rods is carried by a common frame (214) and actuated and controlled by a distinct means (232, 234, 242). A key feature of the gripper head is that each jaw mechanism (216) has an neck portion (244) to offset the actuation means (232, 234) from the moving jaw portion (220). The shroud carries alignment means (82, 206) for precisely orienting the tool relative to a targeted group of rods within the assembly, so that the spacing of the rods is maintained as they are pulled up into the shroud by the gripper head.

Abstract: A fuel assembly with a top nozzle having an adapter plate, at least one guide thimble connected to the adapter plate, and a burnable absorber rod disposed within the guide thimble, includes a releasable latching structure for releasably interconnecting an end of the absorber rod to the adapter plate. The latching structure includes a recess defined in the adapter plate within a passageway through the plate, a mounting body attached to the end of the absorber rod and extending axially upward therefrom through the passageway and above the adapter plate, and a spring latch disposed about the mounting body above the adapter plate. The spring latch has circumferentially spaced latch fingers extending downwardly toward the adapter plate.

Abstract: An apparatus for consolidating spent fuel rods from spent fuel assemblies includes a container with a bottom and front, back, and side walls. The container has a plurality of flutes positioned adjacent to the front wall, and the plurality of flutes defines a plurality of channels. The apparatus also includes a plurality of springs, which are mounted on a support. The springs bear against the flutes and the channels when no fuel rods have been inserted into the container and the support is located proximate the front wall. The springs assist in guiding a fuel rod into a preselected location in the container; the springs are capable of maintaining the fuel rod in the preselected location. Preferably, each spring is a resilient finger that extends outwardly from the support toward the front wall. The support may be a movable sheet. The apparatus advantageously includes a device for moving the support. Such a device may automatically position the support in response to control signals.

Abstract: A system for removing debris from a nuclear fuel assembly includes a work platform disposable on the fuel assembly racks in a spent fuel pol. A support stand is mounted on the work platform and has a sliding support plate movable between a support position engageable with the lower end of the fuel assembly, and a retracted position permitting lowering of the fuel assembly through an opening in the work platform into one of the racks. A tool manipulation assembly is disposable on the platform and includes a rotatable turret-type tool mount carrying four different cleaning tools, including a pick, a brush, a water lance and a water-actuated tweezers. The tool manipulating assembly includes drive means for effecting X-Y-Z movement of the tool mount for working on the fuel assembly. Each tool is resiliently mounted in a tool holder which yields if the tool engages the fuel assembly in a given direction with a predetermined force, generating an alarm signal to prevent damage to the tool assembly.

Abstract: An improved apparatus for applying an end plug to an end of a fuel rod tube includes a housing having spaced inlet and outlet ends adapted to receive the end plug and tube end, respectively, one of three alternative embodiments of a guide arrangement which defines an internal guide channel aligned in tandem with the inlet and outlet ends of the housing along a common axis, and cylindrical ram movable along the axis for engaging and moving the end plug from the inlet end through the guide channel to the outlet end where the plug is applied to the tube end.

Abstract: A method of straightening an irradiated fuel assembly having a plurality of control rod guide thimbles in which some of the guide thimbles are bowed and thus greater in length than other of the guide thimbles comprises the steps of determining the length adjustments required for shortening the respective bowed guide thimbles in order to make their respective lengths generally the same as the other guide thimbles, and then forming expansions in the bowed guide thimbles so as to shorten their respective lengths by the amounts of the length adjustments. Usually, a plurality of expansions are made in most of the bowed guide thimbles at spaced locations between opposite ends thereof. Some of the expansions differ in the amount of shortening from other of the expansions. Also, the total amount of shortening of the bowed guide thimbles is controlled by the number of the expansions and the amount of shortening which results from each expansion.

Abstract: A method and an apparatus for loading containers with individual fuel rods r fuel-rod sections of irradiated nuclear reactor fuel elements are disclosed. In order to ensure maximum safety, cleanliness and close packing when loading the containers, the fuel rods or fuel-rod sections are horizontally front-loaded into the container which is horizontally positioned. The loading aperture is located as closely as possible to the upper inner periphery of the container. Following their insertion, the fuel rods or fuel-rod sections will drop onto the inner wall surface of the container or onto the already existing pile of previously loaded fuel rods or fuel-rod sections. The container for loading with such a method has a loading aperture in the end wall thereof arranged close to the inner periphery thereof for insertion of the fuel rods or fuel-rod sections.

Abstract: Fuel and fertile rod for a nuclear reactor. It comprises a can, a column of fissile and/or fertile pellets within the can and end plugs welded to the two ends of the can. The column of pellets is held in place by two tubular spacers of limited thickness and with rounded edges abutting against the two ends of the fuel column and set with a fixed dimension to the can. The column of fissile and fertile pellets can also be held in place by a supplementary positioning setting of the fertile pellet column.

Abstract: A hatch assembly has an annular seat, a hatch cover and a plurality of latching units. Each latching unit has a slidably supported locking bolt movable generally radially inwardly with respect to the annular seat into a hatch cover locking position and generally radially outwardly into a hatch cover releasing position. In the hatch cover locking position at least one length portion of the locking bolt extends over the hatch cover for maintaining the hatch cover on the annular seat. Each latching unit further has a rotary crankshaft, an operating handle torque-transmittingly connected to the crankshaft for applying a locking torque and an opposite, releasing torque thereto; and a coupling mechanism for connecting the crankshaft with the locking bolt and for converting rotary motion of the crankshaft to linear motion of the locking bolt. The coupling mechanism has a spring for transmitting the locking torque from the crankshaft as a radially inwardly oriented resilient force to the locking bolt.

Abstract: In accordance with the present invention, use is made of the adjacent vertically arranged fuel bundles which surround the empty core position to be filled with the fuel bundle to be inserted. Such use of the adjacent bundles involves the placement upon the top tie plate of each bundle of a separate and individual centering device, each centering device being of a generally box-like cap configuration and engaging the upper tie plate of each fuel bundle. Preferably, each such centering device includes a pair of tapered dowel pins which engage apertures formed in the upper surface of the fuel assembly tie plate so that lateral forces imposed upon the centering device will be transmitted to the upper end of the fuel bundle assembly that may be bowed into the empty core position.

Abstract: An improved apparatus for applying an end plug to an end of a fuel rod tube includes a housing having spaced inlet and outlet ends adapted to receive the end plug and tube end, respectively, one of three alternative embodiments of a guide arrangement which defines an internal guide channel aligned in tandem with the inlet and outlet ends of the housing along a common axis, and a cylindrical ram movable along the axis for engaging and moving the end plug from the inlet end through the guide channel to the outlet end where the plug is applied to the tube end.

Abstract: Apparatus for removing irradiated clips from an irradiated fuel assembly comprises a remotely operated tool including hydraulic or pneumatic jaws operable for withdrawing a clip from fuel rods, while supporting the portions of the fuel rods both above and below the clip to avoid damaging the rods during removal of a clip, and further including a support tube held captive in a carriage mechanism for moving the tool into positions for either clip removal, or for ejection of a removed clip from the tool into a clip disposal basket.

Abstract: A pushing device for removing spent fuel rods from a nuclear reactor fuel assembly comprises a plurality of axially shiftable rods disposed in the same geometric pattern and with the same pitch as the fuel rods. The push rods are mounted at their upper ends to a pressure strip or plate and traverse at their lower ends bores in a guide plate fixed via guide rods to a base plate located on the other side of the pressure plate, the pressure plate being movably secured to the guide rods for linear motion between the base plate and the guide plate. A drive mounted to the base plate is connected to the pressure plate for shifting the latter, while a safety mechanism is provided for interrupting the motion of a push rod if the respective fuel rod is jammed in the fuel assembly.

Abstract: Method intended to form a more or less compact bundle of flexible and oblong objects of reduced cross-section dimensions, such as fuel rods of a nuclear reactor, said objects forming, prior to compacting, an assembly wherein they occupy transversally spaced, parallel positions. According to the invention, this method is characterized in that there is arranged, in a generally vertical direction, a plurality of guiding tubes (2) of which the upper ends (2a) are arranged according to the initial disposition of said object assembly, and of which the lower ends (2b) are arranged according to the desired disposition, the dimension of said guiding tubes (2) being such that in each of them one of said objects may slide by means of gravity, and in that said assembly of objects is brought vertically on top of the plurality of guiding tubes, whereafter each object is introduced by its lower end in the upper end of one of said guiding tubes (2), allowing the assembly of said objects to slide downwardly.

Abstract: A cutter guide fixture for use in removing a top nozzle from the guide thimbles of a fuel assembly includes upper and lower plates coupled to one another for movement of the upper plate relative to the lower plate between upper and lower positions. The plates include aligned pairs of holes within which are mounted a plurality of cutters such that the cutting elements of the cutters are disposed in a common cutting plane. A pair of expansion locking pins are provided at a pair of diagonal corners of the lower plate for releasably attaching the fixture to the top nozzle and positioning the cutters in general alignment with a plurality of passageways defined in the adapter plate of the top nozzle and with a plurality of hollow upper end portions of the guide thimbles inserted and attached in the passageways.

Abstract: In a nuclear fuel assembly having a plurality of separate fuel bundles secured therein in separate compartments, coolant flow paths are provided to enable the flow of coolant between the separate compartments, thereby equalizing the hydraulic pressure between the separate compartments and minimizing the possibility of thermal-hydrodynamic instability between the separate fuel bundles in the nuclear fuel assembly. A plurality of coolant flow paths are formed through solid structural ribs secured to an outer flow channel of the nuclear fuel assembly to permit coolant flow between the separate compartments.

Abstract: A fixture for removing a top nozzle of a reconstitutable fuel assembly held in a fixed position within a work station includes a pair of guide openings in two diagonally opposed corners of its base to movably mount the base on a pair of upstanding guide members of the work station and on the top nozzle in alignment therewith. Also, the fixture includes a pair of hollow expandable split sleeves with wedge pins inserted therein which are operable to lock the fixture to the top nozzle. An arrangement of drive and driven gears connected with a plurality of reaction pins mounted on the base of the fixture are operable to move the fixture base with the top nozzle thereto away from the guide thimbles of the fuel assembly and thereby cause the top nozzle adapter plate to release its connection with the guide thimbles.

Abstract: A fixture for inserting and removing locking tubes into and from locking positions in a top nozzle includes a lower traveling plate and an upper traveling plate disposed above the lower plate. The lower plate has hollow flexure tubes attached to and projecting downwardly therefrom. Each flexure tube has an axially segmented sleeve portion which terminates in a lower segmented rim, with the rim being expandable to a first outside diameter greater than an inside diameter of the locking tube and collapsible to a second outside diameter less than the inside diameter of the locking tube. The upper plate has actuating rods attached to and projecting downwardly therefrom through the flexure tubes.

Abstract: The apparatus is for dismounting nuclear fuel assemblies comprising a skeleton having an upper end piece, a lower end piece, guide tubes connecting the end pieces and fuel rods maintained by grids between the end pieces. The apparatus comprises a cell displaceable vertically in a water tank and provided, at its upper part, with a base plate having an opening for passage of one said fuel assembly and provided with means for gripping an upper part of the bundle of fuel rods. A centering unit is operable by a handling tool and is arranged for gripping the upper end piece of a fuel assembly. The guide tubes may be disconnected from the upper end piece while the bundle of fuel rods is retained in the cell.

Abstract: A grid structure (42) is mounted within the upper portion (24) of a tapered canister (24), for receiving a relatively loosely packed rectangular array of rods (22) and rearranging the rods into a relatively tightly packed rectangular array at the lower end of the grid. The grid structure comprises a multiplicity of flat, vertically oriented trapezoidal segments (78, 80) interconnected to form a plurality of vertically overlapping grid layers (74, 76). The layers alternate between a row orientation and a column orientation, and thus form a substantially continuous honeycomb of longitudinal cells (64) for guiding individual rods. The cross-sectional area of each cell decreases from the uppermost layer (74a) to the lowermost layer (74i) such that the rods are funneled by the cells to form the tightly packed array.

Abstract: A system for consolidating spent fuel rods from spent fuel assemblies includes an operator and control station, a fuel rod transfer tool with a gripper assembly, indexing devices, and a fuel consolidation station. The fuel rod transfer tool and gripper assembly grips a fuel rod and withdraws it from a fuel bundle until it is clear of the bundle. The tool, with the fuel rod drawn up inside it, is moved to another location where it is desired to place the fuel rod; the tool inserts the rod, and the gripper releases it. The fuel consolidation station has a frame that holds two fuel assemblies and a consolidation container. The bottom of the frame rests on the floor of the fuel pool. The top of the frame supports the indexing devices. An indexing device is provided for each of the fuel assemblies and the consolidation container.

Abstract: A machine for examining a nuclear reactor fuel assembly, having a flooring of elongated shape, a rotary container located on a support at one end of the flooring, two vertically arranged rigid structures each consisting of two parallel tubes, a latching mechanism for the fuel assembly, including a large and a small branch which are pivotable with respect to each other, a device for immobilizing the small branch relative to the large branch, a trolley that can be displaced along the flooring towards and away from the support and carries a vertical column along which a bracket with a carriage is movable on which a television system or the like for examining the fuel assembly may be mounted.

Abstract: An apparatus for repairing a protruding portion of an outer grid strap spring includes a support frame made up of interconnected members defining a generally rectangular opening and a plurality of devices mounted on the frame members above and below the frame opening for attaching the frame to the outer strap of the support grid. At least some of the devices are adjustable for securing the frame in a stationary position on the outer strap so that the frame opening is stationarily aligned with the outwardly protruding spring on the outer strap. A pair of spaced apart rails attached to the members on upper and lower sides of the opeing define a guide channel therebetween which extends along the opening in a first direction.

Abstract: A method and an apparatus for loading containers with individual fuel rods r fuel-rod sections of irradiated nuclear reactor fuel elements are disclosed. In order to ensure maximum safety, cleanliness and close packing when loading the containers, the fuel rods or fuel-rod sections are horizontally front-loaded into the container which is horizontally positioned. The loading aperture is located as closely as possible to the upper inner periphery of the container. Following their insertion, the fuel rods or fuel-rod sections will drop onto the inner wall surface of the container or onto the already existing pile of previously loaded fuel rods or fuel-rod sections. The container for loading with such a method has a loading aperture in the end wall thereof arranged close to the inner periphery thereof for insertion of the fuel rods or fuel-rod sections.

Abstract: An apparatus for collapsing and storing used burnable poison assemblies in a reduced volume, which includes a hanger member movable up and down for lifting a holder portion of a burnable poison assembly; a cutter for cutting solid portions of thimble plugs and poison rods of the burnable poison assembly hung on the hanger member; a restricting mechanism for holding the poison rods in restricted positions, restraining spontaneous movements in lateral directions; a gripper member movable up and down and capable of releasably gripping the poison rods; a packing mechanism capable of pushing aside previously stored poison rods in a container to put thereinto the poison rods gripped by the gripper member; and a thimble plug handling mechanism for guiding cut-off thimble plugs onto a receptable tray and placing the same in a container.

Abstract: A canister for the consolidation of nuclear fuel rods (22) comprises an elongated, tapered box (24) of generally rectangular cross-section having upper (42) and lower (44) internal sections, the upper section having rectangular grid structure (46) and the lower section having vertically extending plate members (48). The upper section receives individual fuel rods in a relatively loosely packed rectangular array of rows and columns and urges the rods closer together as they are lowered into the box, such that the rods emerge through the lower end of the grid section in a relatively tightly rectangular array. The number of plate members (48) in the lower section corresponds to the number of rows of fuel rods in the upper section. Each plate has tapered side edges (204) abutting the tapered box, and a plurality of integrally formed, corrugated channels (206) corresponding to the number of rows of fuel rods.

Abstract: An underwater compressing and cutting apparatus for activated or contaminated components of the core of a nuclear reactor by means of which even components of different geometry and different properties can be compressed to reduce their bulk and cut. The apparatus comprises a frame and slidable sleds, one sled having a squeezing jaw and the other sled having a chopping knife which are operated by unidirectional hydraulic cylinders.

Abstract: A fuel transfer system for transferring fuel assemblies through a transfer tube between fuel exchange locations respectively in a fuel storage and handling building and a containment structure of a nuclear reactor includes a segmented track comprising first, second and third track segments and a segmented drive screw comprising first, second and third drive screw segments respectively associated with the fuel storage and handling building, the transfer tube, and the containment structure. Gaps between the successive, corresponding track segments and drive screw segments permit operation of valves for closing the ends of the transfer tube during normal operation of the reactor, which valves are then opened during fuel exchange operations. The adjacent but normally displaced ends of the first and second and of the second and third drive screw segments include respective, mating engagement means.

Abstract: A pushrod assembly including a carriage mounted on a shaft for movement therealong and carrying a pushrod engageable with a load to be moved. A magnet is mounted on a supporting bracket for movement along such shaft. Means are provided for adjustably spacing said magnet away from said carriage to obtain a selected magnetic attractive or coupling force therebetween. Movement of the supporting bracket and the magnet carried thereby pulls the carriage along with it until the selected magnetic force is exceeded by a resistance load acting on the carriage.

Abstract: A method of and an apparatus for cutting a high-activity solid waste, such as a used channel box and a used control rod, to reduce same in size to facilitate its disposal. The channel box is cut axially through opposing corners to produce elongated split portions of an L-shaped in cross section, and the control rod is cut axially through a central portion to produce elongated split portions of an L-shape in cross section. The portions obtained by cutting the channel box and control rod are substantially similar in shape and facilitate storing.

Abstract: A fuel rod-loading fixture for expediting the loading of fuel rods in an empty skeleton of a fuel rod assembly is disclosed herein. The fuel rod-loading fixture generally comprises a square array of non-radioactive "dummy" rods which are all connected at their top ends to a top guide plate. When the rods of the fixture are lowered through the rod-receiving apertures of the grids in the fuel assembly skeleton, they effectively obstruct every other set of mutually aligned, rod-receiving apertures in the grids of the skeleton. The top guide plate includes a plurality of apertures which will automatically register with the remaining sets of mutually aligned apertures in the grids, in order that fuel rods may be inserted through the top guide plate and into the remaining sets of apertures in the grids.

Abstract: Spherolitic cast iron or cast steel containers or nuclear steel elements are modified by replacement of the complex boron steel baskets with stainless steel or austenitic manganese steel lattices therefor and the lattices define vertical compartments in which the fuel rods removed from the elements are received in densest-packed relationship directly or via the intermediary of thin-walled metal sleeves.

Abstract: The specification discloses a device (32) for raising peripheral fuel rods of a fuel assembly for inspection under submerged conditions in a nuclear reactor facility. The device (32) includes a frame comprising top and bottom plates (36, 38) interconnected by rods (40) with an intermediate plate (52) supported therein for vertical movement responsive to a cylinder (60). A yoke (64) is mounted for horizontal movement on the intermediate plate (52) responsive to another cylinder (66) to engage a fuel rod so that it can then be lifted by the first cylinder (60). Proper alignment relative to the peripheral rods of the fuel assembly is accomplished by means of pins (50) which are received in indexing holes (80) of a support plate (68) for the fuel assembly.

Abstract: A plumb nozzle for a nuclear fuel assembly having asymmetric loading of the fuel mass comprising a raised protuberance on the handling tool gripper finger engaging surface of the nozzle to compensate for skewing caused by the asymmetric fuel loading. The protuberance is positioned to be engaged by a gripper finger during handling, loading, or unloading of the fuel assemblies and extends downwardly a predetermined distance with respect to the other gripper finger engaging surfaces so that the fuel assembly hangs plumb.

Abstract: A method of reconstituting a nuclear reactor fuel assembly having a top nozzle subassembly attached to the upper end of its control rod guide thimble wherein the subassembly includes an upper hold-down plate, a lower adapter plate, and a coils spring interposed between the two plates. A force is applied on the hold-down plate to compress the coil spring and transform the subassembly from its operation mode to a reconstitution mode. The wall of the thimble is severed just below a first attaching retainer mounted on the end of the thimble which defines the upward limit movement of the hold-down plate during the operation mode. Containing fingers are placed on the subassembly for removing it as a contained unit. The top nozzle subassembly or a new replacement subassembly is then replaced on the severed thimble in its reconstitution mode and a second attaching retainer is mounted on the upper end portion of the severed thimble in redefining the upward limit movement of the hold-down plate.

Abstract: A tool for the manufacture of a fuel assembly, said tool comprising for each end of an assembly an inner metal plate which can be applied to the bottom of an end member, an outer metal plate which can be displaced, under the action of a jack, along sliding columns fixed to the inner plate, in longitudinal translation with respect thereto and threaded ties traversing corresponding openings in the end member and in the inner and outer plates, able to engage with the internal thread of the guide tubes, and each provided with a head on which is supported a spring for compensating the action of the jack. A method for utilizing the tool is set forth, also.

Abstract: The multiple fuel rod gripper comprises a plurality of split tube collets arranged to be inserted into corresponding tapered holes in a locking plate. When the gripper has been positioned to have a plurality of fuel rods disposed in the holes of locking plate, an actuating mechanism causes the collets to be inserted into the tapered holes thereby causing the fuel rods to be inserted in the collets. The taper of the holes forces the collets into locking engagement with the fuel rods so that the fuel rods may be extracted from the fuel assembly.

Abstract: A pool type nuclear fission reactor has a core, with a plurality of core elements and a redan which confines coolant as a hot pool at a first end of the core separated from a cold pool at a second end of the core by the redan. A fuel handling system for use with such reactors comprises a core element storage basket located outside of the redan in the cold pool. An access passage is formed in the redan with a gate for opening and closing the passage to maintain the temperature differential between the hot pool and the cold pool. A mechanism is provided for opening and closing the gate. A lifting arm is also provided for manipulating the fuel core elements through the access passage between the storage basket and the core when the redan gate is open.

Abstract: Disclosed is a discharge assembly for allowing elongate pins to be discharged from an area of relatively low pressure to an area of relatively greater pressure. The discharge assembly includes a duck valve having a lip piece made of flexible material. The flexible lip piece responds to a fluctuating pressure created downstream by an aspirator. The aspirator reduces the downstream pressure sensed by the duck valve when the discharge assembly is in the open position. This allows elongate pins to be moved through the duck valve with no backflow because the aspirator pressure is less than the pressure in the low pressure area from which the pins originate. Closure of the assembly causes the aspirator static pressure to force the flexible duck valve lip piece into a tightly sealed position also preventing backflow. The discharge assembly can be easily controlled using a single control valve which blocks the flow of aspirator gas and closes the pin passageway extending through the assembly.