Abstract: A gripper mechanism for sampling nuclear fuel pellets at a predetermined depth in a stack of pellets includes a housing and gripping fingers movably mounted to the housing. The fingers are preferably three relatively thin, arcuate-shaped, blade-like fingers angularly displaced from one another for grasping the pellet at spaced locations about its circumference. The fingers have lower facing surfaces which are brought adjacent to one another for engaging and grasping a pellet when the fingers are moved toward their closed position and retracted remote from one another for disengaging and releasing the pellet when the fingers are moved toward their opened position.

Abstract: Method for manipulating and/or storing a nuclear reactor fuel assembly including an elongated skeleton structure with fuel rods and a holding device, which includes placing neutron-absorbing material adjacent the fuel rods, fastening a supplemental body with a handle to the skeleton structure, engaging the neutron-absorbing material with the supplemental body, and fitting a coupling part of the holding device to the handle, and a fuel assembly produced according to the method.

Abstract: Both gadolinia nuclear fuel rods and urania fuel rods are non-destructively tested to determine the enrichment concentration of the fuel pellets therein by serially conveying the gadolinia rods and the urania rod along separate test channels through an active scanner where they are irradiated from a common neutron source, and the neutron-induced gamma ray emissions are counted as a measure of the enrichment concentrations at a multiplicity of points distributed along the rod length. The enrichment counts are corrected for background radiation, variations in fuel density, and, in the case of gadolinia rods, for gadolinia content by passing these rods through a magnetometer.

Abstract: Machine for removing the spacing wire (28) from a nuclear fuel rod (26). The rod (26) is moved through the central passages of first (10) and second (12) rotary parts. The first rotary part (10) has a portion in the form of a milling cutter (30) for detaching the welding spots from the wire (28) on the rod (26). As the rod advances, the wire (26) passes into the holes (32) of the first rotary part (10) and the holes (34) of the second part (12). As these two parts rotate at different speeds, the wire (28) is cut by shearing. Application to the reprocessing of the irradiated fuels of fast neutron nuclear reactors.

Abstract: A pellet collating system includes a tray positioning station located adjacent a pellet collating line with a tray transfer robot located therebetween. The tray positioning station has mobile carts lodged thereat, some supporting pellet supply trays and others supporting pellet storage trays. Pellets on one supply tray and later placed on one storage tray are of the same enrichment. Pellet enrichments on some trays are different from on others. The collating line includes pellet input, work and output stations arranged in tandem. The robot is operable to transfer supply and storage trays one at a time to and from the positioning station and the respective input and output stations. An input sweep head is operable for sweeping pellets onto the work station from a supply tray on the input station. A gripping and measuring head is operable for measuring a desired length of pellets on the work station and then separating the measured desired length of pellets from the remaining pellets, if any.

Abstract: An apparatus for aligning nuclear fuel pellets includes an endless belt for advancing nuclear fuel pellets along a generally linear path in a direction generally coincident with their axes and a stopper element disposed in the linear path for stopping advancement of the pellets therealong for assembling pellets in a row. A detector device senses when advancement of a prescribed number of the pellets in a row have been stopped by the stopper element. A feed mechanism is operable for successively feeding pellet holding trays one at a time to a pellet receiving position along the linear path. A panel defines an inclined path extending from the linear path downward to the one tray disposed at the receiving position. An ejector mechanism disposed along the linear path is responsive to the detector device for pushing the assembled row of pellets sidewise from the linear path along the inclined path of the panel to a groove defined in the one tray.

Abstract: The invention relates to apparatus and a method for facilitating a scratchless insertion of a fuel rod into cellular grids of a nuclear fuel assembly.The apparatus comprises a thin-walled tubular member having an inner diameter substantially corresponding to the outer diameter of a fuel rod, and having a longitudinal slit formed in its wall so as to render the latter resiliently deflectable in a diameter-reducing sense. The method comprises the steps of mounting the thin-walled tubular member in position for protectively enveloping the fuel rod during insertion thereof; inserting the fuel rod into the grids while the tubular member is in place to envelope it; and withdrawing the tubular member from the inserted fuel rod.

Abstract: Apparatus for loading fuel rods in a desired enrichment pattern includes a carrousel, an elongated fuel rod storage magazine, and a fuel rod verify and feed workstation and a magazine holder and indexing mechanism disposed between the carrousel and the magazine. The carrousel has a plurality of gondolas movable mounted thereon for stocking fuel rods of known enrichments. The magazine defines a matrix of elongated slots open at their forward ends for receiving fuel rods. The workstation defines a fuel rod feed path extending between the carrousel and the magazine and is adapted to receive successively one at a time along the feed path at its upstream end fuel rods from selected ones of the carrousel gondolas.

Abstract: A modified inspection apparatus for inspecting nuclear fuel pellets for surface defects includes a pellet guide chute assembly extending through an ultrasonic inspection chamber. The guide chute assembly has a support substrate and a pair of elongated plates attached on respective upper adjacent sides of the substrate. The substrate is composed of a pair of elongated wall sections rigidly attached together to have a V-shaped configuration in cross section. The plates are adjustably attached on the substrate wall sections for supporting a nuclear fuel pellet between and on adjacent longitudinal portions of the plates located in the inspection chamber.

Abstract: A method of 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: In an automated first weld apparatus, a transporter conveys nuclear fuel cladding tubes successively to a welding station where a separate end plug is welded to an open end of each tube. Thereafter, the transporter indexes the tubes successsively through a cooldown station where the weld is cooled, to a reader station where a unique end plug serial number is read, and then to a succession of inspection stations where the internal and external weld characteristics are automatically examined. The resulting inspection data is correlated with the associated serial number for record purposes and tested against quality assurance standards pursuant to sorting the tubes into accepted and rejected lots.

Abstract: A method and apparatus for separating the fuel rods (15) in a fuel element 8), whereby the former are retained in a bird cage arrangement (16, 18) between a head piece (19) and a foot piece (19'). The fuel elements (8) is located on a support table (6) with the help of a clamping arrangement (10). Before the fuel rods can be separated, the head piece and the foot piece are removed. In order to simplify removal of the fuel rods from the fuel element, to save space, and to minimize any risk of breakage after removal of the head piece (19) and the foot piece (19'), the bird cage arrangement (16,18) is progressively stripped from one layer of fuel rods to the next and from around the fuel rods. The exposed fuel rods are then lifted out of the fuel element (8) layer by layer and reshuffled in a more compact arrangement. A cutting tool (24), provided with a cutting disk head (26), is used to strip and separate the fuel rods with the help of a grappler (28).

Abstract: A system for loading nuclear fuel pellets into tubular fuel pins. The system includes means for locating a fuel pin in registry with a pellet channel to enable a pellet stack to be displaced lengthwise into the fuel pin. The pellet channel and the pin locating means are mounted on a common structure. Linear vibrator means comprise first driving means arranged to urge the common structure in a lengthwise direction, and second driving means arranged to urge the common structure in a substantially perpendicular direction, so that the common structure is driven in a closed loop. Sensing means provide a signal upon cessation of pellet motion upstream of the fuel pin locating means. Means operable in response to said signal automatically adjust the phase relationship between said first and second driving means to effect reverse motion of the pellets.

Abstract: A pellet collating system includes a tray positioning station located adjacent a pellet collating line with a tray transfer robot located therebetween. The tray positioning station has mobile carts lodged thereat, some supporting pellet supply trays and others supporting pellet storage trays. Pellets on one supply tray and later placed on one storage tray are of the same enrichment. Pellet enrichments on some trays are different from on others. The collating line includes pellet input, work and output stations arranged in tandem. The robot is operable to transfer supply and storage trays one at a time to and from the positioning station and the respective input and output stations. An input sweep head is operable for sweeping pellets onto the work station from a supply tray on the input station. A gripping and measuring head is operable for measuring a desired length of pellets on the work station and then separating the measured desired length of pellets from the remaining pellets, if any.

Abstract: A rod arraying system for nuclear fuel rods or burnable poison rods. A support structure positions a consolidation canister vertically to receive the rods. A rod loading pattern provides a gap between rods to allow projections to hold each rod in position. One or more rod arraying devices positioned vertically along and inclined toward the canister provide a triangular pitch loading configuration. A guide assembly slidably mounted on the mounting base of the rod arraying device has two guide plates with scalloped edges. The guide plates are offset relative to each other with one being cycled back and forth by an air cylinder to allow individual loading of fuel rods one row at a time. The inclined weight of the guide plates keeps them in position against the rods to prevent unwanted shifting of rods during the loading operation.

Abstract: A continuous dissolution apparatus for spent nuclear fuel in which a container (2) for holding a dissolution processing solution (1) is continuously supplied with nitric acid from a feed port (3), while the processing solution is continuously drawn out from an outlet (4). Baskets (71-74) in the container are packed with spent-fuel chops (6), which are continuously dissolved by the processing solution. The container is provided with a solution reserving section (4) for lowering the concentration of radioiodine contained in the dissolution processing solution, and a partition wall (10) is formed between the solution reserving section and a container body. The dissolution processing solution having overflowed from the upper edge of the partition wall flows into the solution reserving portion (14) through a perforated plate column (11).

Abstract: A method for reparing bent mixing vanes in a nuclear reactor fuel assembly is described, including the steps of introducing an apparatus having movable blades below a grid with a mixing vane; opening the blades; withdrawing the apparatus so that a blade abuts and straightens the bent mixing vane; closing the blades; and fully extracting the apparatus from the fuel cell.

Abstract: A straightening device (16) for bent fuel assembly alignment pins (12) in an upper core plate (10) comprises elongated mast (22) having an upper and lower portion, bail (25) secured to the upper portion and cross member (28) secured to the lower portion. At one end of the cross member (28) is attached pin straightening assembly (19), the other end having counterweight (31) to assure a horizontal orientation of the cross member (28). Pin straightening assembly (19) is further comprised of housing (37) having wedge-shaped adjustable shim (61) connected to its top surface, the housing (37) secured to the cross member (28) by baseplate (34). Four axially compressible and laterally deformable compression springs (41) are connected between baseplate (34) and housing (37) to provide angular and translational compliance for housing (37).

Abstract: An improved system for repairing and reconstituting a fuel rod assembly in the spent fuel pool of a nuclear power plant is disclosed herein. The improved system includes a height-adjustable elevator and carriage assembly for lifting and inverting a pair a fuel assemblies with their bottom ends adjacent one another, a length-adjustable rod handling tool having a gripper for gripping, lifting, lowering and ungripping a fuel rod, and a dual-axis tool positioner mountable over the bottom ends of the inverted, adjacent fuel assemblies. The tool positioner includes a funnel-shaped tool guide that is movable over the bottom ends of the fuel assemblies for receiving and positioning the gripper of the rod handling tool. The improved system may be adjusted for use in spent fuel pools of substantially different dimensions and water levels without the need for additional parts, and may be operated by only two technicians.

Abstract: A fuel bundle in which the fuel rods are supported by top and bottom plates and held together by axially spaced straps. Several of the fuel rods are formed as tie rods. Each tie rod has a flat key at the bottom which is passed through a slot in the bottom plate. By turning the tie rod, the key is rotated to a locking position in which its axial movement is prevented. At the top, each tie rod has a flattened plug which is threaded on its rounded sides to receive a nut that has a crimping lip. The plug extends through a slot in the top plate and is threaded to the nut and the crimping lip is crimped to the plug. The tip of the plug is flat. During reconstitution of the fuel bundle, the crimp on each tie rod is broken and the nut is unscrewed while the tip of the plug is held. The top plate is then removed and each tie rod is then turned so that the key can be passed through the slot in the bottom plate. The tie rods may thus be removed and the bundle disassembled without access to the bottom plate.

Abstract: In order to multiply by three or four the combustion level of nuclear fuel pellets in fast neutron nuclear reactors, it is proposed that following a normal irradiation period of said pellets in the reactor core, that the irradiated can be replaced by a new can with an internal diameter slightly exceeding that of the first can. Thus, the pellets can undergo a new irradiation cycle in the reactor core. Preferably, the can is destroyed by progressive local melting over its entire length and the new can is preheated to facilitate the introduction of the pellets.

Abstract: The invention relates to apparatus and a method for facilitating a scratchless insertion of a fuel rod into cellular grids of a nuclear fuel assembly.The apparatus comprises a thin-walled tubular member having an inner diameter substantially corresponding to the outer diameter of a fuel rod, and having a longitudinal slit formed in its wall so as to render the latter resiliently deflectable in a diameter-reducing sense. The method comprises the steps of mounting the thin-walled tubular member in position for protectively enveloping the fuel rod during insertion thereof; inserting the fuel rod into the grids while the tubular member is in place to envelope it; and withdrawing the tubular member from the inserted fuel rod.

Abstract: During the dismantling of a nuclear reactor fuel assembly, there is a simultaneous gripping of all the rods (a) arranged in square grid form in said assembly using a device (10) which effects a clamping or locking at the end of the rows of rods. For this purpose, device (10) has passageways (26) penetrated by the ends of two adjacent rows of rods (a). In said passage ways are trapped mobile members (34, 34') arranged in such a way that each rod is placed between two adjacent members. By applying a locking force on the mobile end members in each passageway (26), each rod is gripped between two members (34, 34'). Preferably, the mobile members (34, 34') are provided with abutments limiting the locking or clamping force individually applied to each rod. For filling the gaps of the grid of rods (a) corresponding to the locations occupied by the guide tubes in the assemblies, rollers (78) are placed in the passageways (26) at the corresponding locations.

Abstract: In order to transfer a bundle of rods of or from a nuclear fuel assembly into a storage case, the bundle is placed in a waiting position above a cassette provided with recesses. The rods are then introduced into the recesses by lowering them by gravity. When the cassette is full, it is brought into the extension of the case by interposing a transformation member. By simultaneously exerting a thrust on all the rods, the latter are compactly transferred into the case.

Abstract: The invention is a method for the storage in a storage room (9) of radioactive material and particularly for the temporary storage of radioactive nuclear fuel from nuclear reactors and of non-reprocessed radioactive material.A remote-controlled robot arrangement, comprising a transfer robot (4) and a lifting and carrying robot (5), is designed to fit into a lift (8) for moving the material from ground level to the storage room, to transfer the material into double-walled containers (1), and to carry stacks of containers. The material is transferred by the transfer robot (4) to and from the double-walled containers (1). The containers are provided with safety arrangement (2) with three safety locks to prevent the radioactive material from escaping during transfer.Heat removal from the double-walled containers (1) is effected by means which make the heat available for practical use and maintain the correct temperature in the containers.

Abstract: A tooling system and method for remotely removing a rod or other component located between the top and bottom nozzles of a fuel rod assembly is disclosed herein. Generally, the tooling system comprises a grinding mechanism including a carbide burr and a high speed air motor for grinding an opening through the adapter plate of the top nozzle of a size sufficient to allow the withdrawal of said component therethrough, a housing fixture connected to the carbide burr of the grinding mechanism for positioning the burr over a point in the adapter plate adjacent to the component to be removed, and an engagement assembly connected to the grinding mechanism for moving the carbide burr into grinding engagement with the adapter plate, and a gripping apparatus insertable through the hole produced by the grinding mechanism for gripping the rod or other component and withdrawing it through the opening.

Abstract: A method 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: For sampling a section of a tube in a nuclear fuel assembly comprising a skeleton formed by two end-pieces joined by tubes fixed to the end-pieces an opening for the extraction of the section through the upper end-piece is cut out with a milling cutter. Through the inside and by means of a cutting tool, the spacer tube is cut off at a level beneath the junction with the upper end-piece by means of a rotary tool introduced through the upper end-piece and the latter is extracted through the opening.

Abstract: Apparatus for releasably engaging an elongated member that is releasably connected to the top nozzle of a nuclear reactor fuel assembly. The top nozzle has an adapter plate disposed at its lower end having at least one passageway therethrough through which the elongated member is disposed. The elongated member has a releasable latching structure at one end that is able to be engaged by the apparatus, having at least one latching member movable between a latched position in which the latching member is able to engage said adapter plate and secure the absorber rod in a stationary relationship with respect to the adapter plate and an unlatched position in which the latching member is able to disengage from said adapter plate so that the elongated member be removed from the fuel assembly.

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: Bodies such as nuclear fuel pellets are formed into a stack in a stacking lane (34) and the length of the stack is measured at intervals by device (40) to determine if the partly-formed stack is drifting away from a target length. Pellets are issued into the stacking zone (34) by a selector mechanism (32), the input of which receives pellets from three lanes (24, 26, 28) containing oversize, undersize and intermediate size pellets and the pellets issued to the stacking lane (34) are selected under the control of microprocessor-based unit (18) according to the extent of any drift from the target value. The pellets in lanes (24, 26, 28) are derived from a common supply (12) following segregation by a diverter mechanism (22) controlled by unit (18) in accordance with length measurements made by measuring device (16).

Abstract: A fuel assembly fabrication apparatus includes a stationary support fixture and a slide fixture mounted to one end portion thereof for movement therealong. Clamp structures are disposed in spaced relation longitudinally along the stationary support fixture. One clamp structure is mounted on the movable slide fixture and supports a top nozzle and an uppermost one of a plurality of grids of a fuel assembly. The remaining clamp structures are mounted on the stationary support fixture and support a bottom nozzle and the remaining grids. The clamp structures respectively support the top nozzle and uppermost grid and the bottom nozzle and remaining grids in generally parallel relationship with passageways defined in the top and bottom nozzles and sleeves connected on the grids being aligned for slidably receiving therethrough a plurality of guide thimbles and an instrumentation tube of the fuel assembly for attachment to the nozzles and grid sleeves.

Abstract: For safety in storage and transport of nuclear fuel elements outside a nuclear reactor core, they are provided with a coating of a neutron-absorbing substance from a liquid phase, e.g. by immersion, spraying or pouring, utilizing a melt, a solution or immersion so that the possibility of critical mass attainment is eliminated or minimized.

Abstract: For safety in storage and transport of nuclear fuel elements outside a nuclear reactor core, they are provided with a coating of a neutron-absorbing substance from a liquid phase, e.g. by immersion, spraying or pouring, utilizing a melt, a solution or immersion so that the possibility of critical mass attainment is eliminated or minimized.

Abstract: A spacer sleeve is installed within an instrumentation tube of a nuclear fuel assembly comprising two end nozzles connected by tie rods and a plurality of fuel rod supporting grids distributed at axial intervals along the tie rods. The instrumentation tube has a first end received in an initially blind bore formed in one of the end nozzles and communicating with the outside by a coolant restriction.

Abstract: An apparatus for automatically loading one or more kinds of nuclear fuel pellets in fuel cladding tubes for producing nuclear fuel rods comprises at least one pellet transporting tray transferred from a tray stacking unit and provided with a plurality of grooves on which the fuel pellets are mounted, at least one pellet aligning tray provided with a groove selectively connected with one of the grooves of the pellet transporting tray at one end of the aligning tray, and a fuel cladding tube supporting device located in the vicinity of the other end of the aligning tray and adapted to support a number of fuel cladding tubes so that a selected one fuel cladding tube is operatively connected to the aligning tray. The fuel pellets are transferred from the transporting tray into the aligning tray by means of a pushing device and the row of the pellets transferred on the groove of the aligning tray is moved forwardly until it abuts against a stopping mechanism located in association with the aligning tray.

Abstract: A position sensing mechanism, for use with a nuclear fuel transfer system which employs an underwater cart having a pivotable container to receive fuel assemblies, employs mechanical elements below water and a cable which carries movement of the mechanical elements to a switch assembly at a dry location. The mechanical elements include an anchor element which is affixed to an upender mechanism, which selectively moves the container between horizontal and upended positions when the cart is located at a fuel transfer station, and a feeler mechanism which is displaced by the cart. The feeler mechanism includes a pivotably mounted swing arm and one or more pulleys. The cable is attached to the anchor elements and is guided by the pulleys. The switch assembly includes a further pulley having cams to actuate microswitches when the cable is displaced by the anchor element and feeler mechanism. A temperature compensator is spliced into the cable to keep its length constant despite temperature variations.

Abstract: A nuclear fuel rod loader for pulling fuel rods into a fuel assembly skeleton has a rod gripper with slots defining fingers. The rod gripper passes through the grids of the skeleton on its way to a fuel rod magazine. An inner shaft of the rod gripper spreads open the fingers to engage a groove in the cavity of the end plug of the fuel rod. The rod gripper is retracted, pulling the coupled fuel rod into the fuel assembly skeleton. The rod gripper has a chamfer surface at the closed slot end of each slot to avoid the rod gripper damaging a dimple during entry into the grids of the fuel assembly skeleton. The rod gripper has a stress relief surface at the closed slot end of each slot to avoid failure in the flexing fingers.

Abstract: An apparatus and method for adjusting the level of nuclear fuel rods in a fuel assembly is disclosed, and which comprises a tool composed of an expander having a pair of parallel, laterally spaced apart and flexible arms which have first ends which are interconnected to each other, and opposite free ends. The tool further includes an actuator disposed between the free ends of the arms, and the free ends of the arms and the actuator mount cooperating wedge surface means, whereby relative longitudinal movement between the expander and actuator causes the arms to separate a predetermined maximum distance. In use, the tool is inserted into the fuel assembly with the free ends of the arms located between the end of a misaligned fuel rod and the nozzle, and the actuator is then longitudinally advanced to separate the arms to the predetermined maximum distance, which serves to move the misaligned rod to its proper level.

Abstract: An 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 method for testing vertically disposed fuel rods combined in fuel rod clusters or fuel assemblies in rack positions of a fuel assembly rack of a water-cooled nuclear reactor includes inserting a holding device into first and second unoccupied rack positions while maintaining an unoccupied third rack position therebetween, inserting a fuel assembly to be tested into the third rack position with a lifting device, locking the fuel assembly to the holding device while the fuel assembly is in the third rack position, moving the fuel assembly vertically upward with the holding device, interrupting the upward motion of the fuel assembly, subsequently inserting a probe with a test device into spaces between the fuel rods in a testing operation, moving the fuel assembly vertically downward with the holding device after completing the testing operation until the fuel assembly is deposited in the third rack position, removing the fuel assembly with the lifting device, and depositing another fuel assembly to be tested

Abstract: A handling apparatus which is intended primarily for operations involving pulling and pushing nuclear fuel rods which are carried out when dismantling assemblies, comprising a handling head in which there are provided a plurality of cylinders (6) in which grippers are slidable, formed by two coaxial parts (4, 10) by means of pistons (4a, 4b) which are fixed with respect thereto. Said pistons define three annular spaces (A, B, C) which are supplied by three individually controllable hydraulic fluid circutis (La, Lb, Lc). Such fluids provide for opening and sliding movement of the grippers with respect to the head as well as control of the maximum admissible force in respect of traction or compression on the grippers.At the upper end of each gripper two travel limit switches give the individual situation of each thereof.

Abstract: An apparatus for consolidating the nuclear fuel elements originally arranged in a square pattern into a truss of tightly packed elements comprises a vertical quiver of pyramidal shape having lateral surfaces converging downwardly and a rectangular cross-section. Two opposite faces of the quiver are formed with projections of downwardly increasing amplitude for rearranging the elements in a triangular pattern when they are lowered into the quiver. Dividing walls perpendicular to those faces which are provided with projections separate and guide rows of elements at the top part of the quiver. A grid at the top of the quiver comprises compartments for introducing elements and consists of several fractions which may be moved apart from each other and brought together along a direction parallel to the dividing wall.

Abstract: A spring retainer apparatus includes a pair of assemblies adapted to engage and retain pairs of back-to-back springs of a fuel assembly grid in retracted positions for facilitating the loading of fuel rods into cells of the grid in a scratch-free manner. Each spring retainer assembly has elongated holder bars and a handle bar interconnecting the holder bars together at the same ends thereof so that the holder bars can be concurrently extended along and aligned with the straps of the grid which define the pairs of springs. Also, members are supported by each holder bar which correspond in number to the pairs of springs defined by the straps aligned with the holder bar. Each member has a terminal end configured to engage and retain the springs in their retracted positions when the respective holder bar supporting the member is aligned with and moved toward the springs.

Abstract: An apparatus for adjusting the level of nuclear fuel rods in a fuel assembly is disclosed, and which comprises a tool composed of an expander having a pair of parallel, laterally spaced apart and flexible arms which have first ends which are interconnected to each other, and opposite free ends. The tool further includes an actuator disposed between the free ends of the arms, and the free ends of the arms and the actuator mount cooperating wedge surface means, whereby relative longitudinal movement between the expander and actuator causes the arms to separate a predetermined maximum distance. In use, the tool is inserted into the fuel assembly with the free ends of the arms located between the end of a misaligned fuel rod and the nozzle, and the actuator is then longitudinally advanced to separate the arms to the predetermined maximum distance, which serves to move the misaligned rod to its proper level.

Abstract: An apparatus for inserting rods of a rod bundle from a nuclear reactor fuel assembly into a vessel includes a dense-setting device including: a holding cage for laterally holding the rods together in a given dense packing with mutually parallel longitudinal axes, the cage having a bottom on which one end of each of the rods stand; an insert associated with the holding cage having two ends and guide channels receiving the rods, the guide channels defining an outlet cross section at one end near the bottom with outlet openings disposed according to the given dense packing, and the guide channels defining an inlet cross section at the other end at which the rods are inserted with inlet openings disposed according to the position of the rods in the rod bundle, the insert including a plate having the inlet openings formed therein defining the inlet cross section, the plate being movable toward the outlet cross section against a spring up to a stop; and a pulling tool for pulling the insert out of the holding cage

Abstract: The system of the invention includes a downender station 10 which receives and secures a spent fuel assembly 20 in a vertical disposition and is then pivoted to a horizontal position after the upper nozzle has been removed, and a second station 12 generally aligned with the first station includes a multiple rod gripper 56 which is used to grip onto the exposed fuel rod ends and pull the fuel rods to an upper horizontal location in the second station, with horizontal and vertical combs 60 and 62 maintaining the original square pitch array of the rods, and the rods are then dropped into a reconfiguring structure 70 where they assume a more compact array, the rods then being pushed by pusher 74 into a storage canister 26 carried by the downender below the fuel assembly 20. The arrangement permits compacting fuel rods from two fuel assemblies into a storage canister 26 having approximately the same transverse cross-sectional area as a single fuel assembly.

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 pulling elements extend through the fuel rod container and through the transition funnel. The pulling members each includes a renewable metal cap and an electrode for welding the cap to the top end of an individual fuel rod 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: A fuel transfer system for a fuel container (26) within a nuclear reactor facility includes a transport car (10) for transporting the fuel container (26) through a transfer tube between a reactor containment handling pool and a spent fuel storage pool. The system includes upending mechanisms for automatically pivoting the fuel container (26) from its horizontal transport mode to its vertical, fuel loading-unloading mode when the fuel container (26) enters one of the pools in response to the translational drive of the transport car (10). The upending mechanisms include slotted brackets (46, 146) mounted upon the fuel container (26), and pivotable pick-up bars (44, 144) for engaging the brackets (46, 146) of the fuel container (26).

Abstract: Horizontal fuel element bundle shears have a stepped blade and a horizontal agazine for accommodating an undismantled uclear reactor fuel element which is to be cut up. In the fuel element bundle shears, the nuclear reactor fuel element, for the cutting operation to be performed, is pushed with a stepwise movement through a magazine opening in front of which the stepped blade is displaceable in a direction perpendicular to the longitudinal axis of the fuel element. Each portion of the stepped blade has a cutting edge. In order to achieve a lower rate of wear of the stepped blade while at the same time obtaining a good cut and a low cutting force, the stepped blade has two cutting edges which are separated from each other by a step, thereby forming two blade portions which are in superposed relationship with each other.