Abstract: The apparatus for positioning a fuel assembly (10) comprises, on a respective side of the core support plate (19) and the upper core plate (9) directed towards an endpiece (15, 14) of the fuel assembly (10) at least two projecting positioning pins (16, 22) adapted to engage in openings in the lower endpiece (15) or upper endpiece (14). Each of the positioning pins (16, 22) is fixed in a blind opening (24) comprising a threaded bore and a support surface perpendicular to the axis of the blind opening (24) and comprises a flange adapted to come into contact with the support surface when the positioning pin (16, 22) is screwed into the threaded bore. A gudgeon enables the positioning pin to be locked to secure it against unscrewing. The invention also relates to a process and apparatus for replacing damaged positioning pins on the core support plate (19) or on the upper core plate (9).

Abstract: An improved method of increasing the power output of an existing nuclear power plant includes increasing the thermal power output of the plant's nuclear island and constructing of an auxiliary BOP to handle the increased thermal power. The thermal power of the nuclear island can be increased such as by increasing the thermal power of the plant's reactor, by replacing the plant's steam generator with one that is more efficient, and by increasing the flow rate and/or change in temperature of a coolant in a secondary cooling loop of the plant. The thermal power of the reactor can be increased such as by replacing existing cylindrical fuel rods with fuel rods having a relatively greater surface area to volume ratio and/or by increasing the flow rate and/or the change in temperature of a coolant of a primary cooling loop. The auxiliary BOP can be constructed while the plant is in operation, and can then be connected with the nuclear island during a maintenance operation on the reactor.

Abstract: A measuring head is used in measuring an assembly part of a nuclear facility, such as a fuel rod, a fuel assembly box, or a spacer of the fuel assembly. The measuring head is capable of augmenting a comparatively large data base representing the overall aging state of the fuel elements in a simple manner and within a short measuring time. The measuring head has a probe tip on the sensor housing and a layer thickness measuring probe is integrated into said probe housing, said measuring probe working according to the eddy current principle. The contour or the diameter of the fuel rod can be determined by the measured deflection of the probe.

Abstract: A method and apparatus is disclosed for smoothly inserting a fuel rod loader through the skeleton of a fuel cell and then for pulling an attached fuel rod into the fuel rod skeleton while keeping the fuel rod under constant tension and preventing the bowing of the fuel rod. The pulling mechanism comprises a smooth collet with a smooth bullet end cap for guiding the puller mechanism into and through the skeleton where the bullet end cap is removed and the fuel rod is attached with a unique ball and slide mechanism actuated by a long puller rod that grabs the end of the fuel rod by a forward motion of the puller rod and is easily removed from the fuel rod by reversing this motion once the fuel rod is in place.

Abstract: The diameter of a segment of a peripheral rod in a fuel assembly is measured between two successive spacer grids. A measuring tool is positioned at a level situated between the two successive spacer grids, the tool comprising two measuring fingers that are free to move relative to each other in a first horizontal direction and that are urged towards each other by a resilient return arrangement, and that extend in a second horizontal direction perpendicular to the first horizontal direction. The measuring fingers are moved in the second horizontal direction towards a rod so as to put two contact pieces of the measuring fingers into contact with two zones of the rod segment. The measuring fingers are moved in the vertical axial direction of the rod along its segment situated between the two spacer grids and an electromagnetic sensor is used to measure the distance between the measuring fingers in the first horizontal direction while the measuring fingers are being moved axially.

Abstract: A modular reactor servicing platform for a nuclear reactor is provided. The modular servicing platform includes a plurality of modular sections coupled together, a support structure coupled to the coupled together modular sections, a center access opening, and a refuel access channel extending from the center access opening to an outer edge of the platform forming a substantially C-shaped servicing platform. Each modular section includes a plurality of interconnecting beams, and at least one floor panel attached to and covering the beams.

Abstract: A reactor servicing platform for a nuclear reactor is provided. The nuclear reactor includes a reactor pressure vessel positioned in a primary containment and at least one refuel bridge. The primary containment includes a refueling floor. The servicing platform, in an exemplary embodiment, includes a frame, a support structure, and a floor covering the frame. The floor includes a reactor access opening sized to permit access to the reactor pressure vessel.

Abstract: An apparatus, transfer cask, system, and method for defueling a nuclear reactor and transferring spent nuclear fuel from a spent nuclear fuel to a storage cask for long terms storage. In one aspect, the invention is an apparatus for use in transferring a canister of spent nuclear fuel from a transfer cask to a storage cask, the apparatus comprising a radiation absorbing shield surrounding a portion of a hole through which the canister can pass; means for securing the apparatus to the top surface of the storage cask; means for securing the bottom surface of the transfer cask to the apparatus; wherein the transfer cask securing means and the storage cask securing means are positioned on the apparatus so that when the apparatus is secured to both the transfer cask and the storage cask, the cavity of the transfer cask, the hole, and the cavity of the storage cask are substantially aligned; and means for moving the bottom lid in a horizontal direction once the bottom lid is unfastened from the bottom surface.

Abstract: The present invention relates to a zirconium alloy having excellent corrosion resistance and mechanical properties and a method for preparing a nuclear fuel cladding tube by zirconium alloy. More particulary, the present invention is directed to a zirconium alloy comprising Zr-aNb-bSn-cFe-dCr-eCu (a=0.05-0.4 wt %, b=0.3-0.7 wt %, c=0.1-0.4 wt %, d=0-0.2 wt % and e=0.01-0.2 wt %, provided that Nb+Sn=0.35-1.0 wt %), and to a method for preparing a zirconium alloy nuclear fuel cladding tube, comprising melting a metal mixture comprising of the zirconium and alloying elements to obtain ingot, forging the ingot at &bgr; phase range, &bgr;-quenching the forged ingot at 1015-1075° C., hot-working the quenched ingot at 600-650° C., cold-working the hot-worked ingot in three to five passes, with intermediate vacuum annealing and final vacuum annealing the worked ingot at 460-540° C.

Abstract: A method for storing nuclear fuel in a container (10) including a concrete body and a fuel receiver embedded in the concrete body, comprises the steps of: providing formwork (62) for the concrete body and supporting the fuel receiver within the formwork; placing the formwork in an immersed position in a pool (54) containing a body of water; placing concrete in the immersed formwork (62); and removing the formwork with the concrete body cast therein from the pool (52).

Abstract: A lifting support for a boiling water reactor nuclear fuel assembly comprising a grappling head configured to allow attachment to a lifting device, a body with an upper end and a lower end, the upper end connected to the grappling head, the body configured to be inserted into a water channel of a boiling water reactor nuclear fuel assembly, and an end connected to the lower end, the end configured to be accepted by the nuclear fuel assembly.

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sets atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190). In a second embodiment the integrated head assembly (1100) includes a missile shield (1400) and CRDM cooling system (1600) that permits access to individual CRDMs from above.

Abstract: This disclosure describes a method for metallurgically bonding a complete leak-tight enclosure to a matrix-type fuel element penetrated longitudinally by a multiplicity of coolant channels. Coolant tubes containing solid filler pins are disposed in the coolant channels. A leak-tight metal enclosure is then formed about the entire assembly of fuel matrix, coolant tubes and pins. The completely enclosed and sealed assembly is exposed to a high temperature and pressure gas environment to effect a metallurgical bond between all contacting surfaces therein. The ends of the assembly are then machined away to expose the pin ends which are chemically leached from the coolant tubes to leave the coolant tubes with internal coolant passageways. The invention described herein was made in the course of, or under, a contract with the U.S. Atomic Energy Commission.

Abstract: A plurality of reactor tubes contained in a reactor vessel are filled with at least one catalyst by automatically measuring the catalyst by weight with equipment located at the site of the reactor vessel, and dispensing the measured catalyst into a plurality of reactor tubes.

Abstract: A system and method for moving a canister of spent nuclear fuel from a first location, which may be within a nuclear power generation facility to a second location such as a storage cask that is used for short-term or long-term storage of spent nuclear fuel includes a first lifting mechanism for engaging a transfer cask and a second lifting mechanism for engaging and lifting the canister of spent nuclear fuel. Preferably, the method is practiced by first positioning a canister of spent nuclear fuel within the transfer cask and then engaging the transfer cask with the first lifting mechanism. The canister is engaged with the second lifting mechanism. The transfer cask having the canister positioned within is moved to the vicinity of a storage cask, and the canister is lowered from the transfer cask into the storage cask by the second lifting mechanism without disengagement of the first lifting mechanism from the transfer cask.

Abstract: A method of inspecting an operation of sealed closure by welding an end opening of a filling channel axially traversing an upper plug for closing the cladding of a fuel rod for a nuclear reactor, the cladding of the rod containing a plurality of pellets of nuclear fuel stacked in the axial direction of the cladding and two closure plugs, one of the plugs or the upper plug being traversed axially by the channel for filling the cladding of the rod with an inert gas and the sealed closure by welding of the filling channel of the upper plug being carried out after filling the cladding with inert gas, in a filling apparatus, by melting central part of the end of the upper plug adjacent to the opening of the filling channel, this method allowing for inspection of the conditions for implementing and carrying out the sealed closure of the upper plug by welding, efficiently and without extending the time needed for the manufacture of the fuel rod.

Abstract: A system and method for moving a canister of spent nuclear fuel from a first location, which may be within a nuclear power generation facility to a second location such as a storage cask that is used for short-term or long-term storage of spent nuclear fuel includes a first lifting mechanism for engaging a transfer cask and a second lifting mechanism for engaging and lifting the canister of spent nuclear fuel. Preferably, the method is practiced by first positioning a canister of spent nuclear fuel within the transfer cask and then engaging the transfer cask with the first lifting mechanism. The canister is engaged with the second lifting mechanism. The transfer cask having the canister positioned within is moved to the vicinity of a storage cask, and the canister is lowered from the transfer cask into the storage cask by the second lifting mechanism without disengagement of the first lifting mechanism from the transfer cask.

Abstract: The basket comprises a bundle of tubes (10) connected to each other by an assembly structure (14) so as to form a regular network of compartments (16). Cross pieces (12) are placed between the tubes (10) so as to define a second wall approximately continuous around each compartment (16) surrounding the first wall materialized by tubes (10) and at least partially in contact with this wall. Thus, baskets with compartments with arbitrarily shaped cross sections, and particularly square, rectangular, hexagonal or circular cross sections, can be made for a limited cost.

Abstract: There is provided a nuclear power station primary pump of the type comprising a drive shaft for rotating a wheel, a heat exchanger, a thermal barrier cover comprising a peripheral skirt provided at its base with a circular end wall, and a diffuser comprising a peripheral skirt provided at its base with a rim. The circular end wall co-operates with the base of the heat exchanger to define a bottom chamber for cold water and includes a central bore provided with a succession of circumferential and superposed rings forming a lip seal of the labyrinth type, and a space is formed between the thermal barrier cover and the diffuser to maintain stagnant cooling fluid.

Abstract: A method and apparatus is disclosed for smoothly inserting a fuel rod loader through the skeleton of a fuel cell and then for pulling an attached fuel rod into the fuel rod skeleton while keeping the fuel rod under constant tension and preventing the bowing of the fuel rod. The pulling mechanism comprises a smooth collet with a smooth bullet end cap for guiding the puller mechanism into and through the skeleton where the bullet end cap is removed and the fuel rod is attached with a unique ball and slide mechanism actuated by a long puller rod that grabs the end of the fuel rod by a forward motion of the puller rod and is easily removed from the fuel rod by reversing this motion once the fuel rod is in place.

Abstract: A preventive maintenance method and apparatus for a structural member in a reactor pressure vessel according to the present invention reduce a tensile residual stress on a surface of the structural member by impinging a water jet from a nozzle onto a plane surface of a deflector to thereby change direction of flow of the water jet, and impinging the water jet after being deflected onto the surface of the structural member. This method and apparatus are applicable to a narrow space portion, and can improve a residual stress on the surface of the structural member and can also prevent damage such as stress corrosion cracking.

Abstract: An automated machine for loading nuclear reactor fuel, BP, or APSR pellets from small trays having rows of pellets into reactor rods of long length wherein the pellets are individually counted and loaded into rows of a loading tray according to the desired number of pellets per row and total number of pellets per tray with the loading tray controls being moved to a que tray where they may be weighted and there from to an unloading tray for sequential row loading into the reactor rod.

Abstract: The invention comprises an apparatus to repair a fuel assembly to accomplish a load lift comprising a main body, an upper section, a connection configured between the main body and the upper section and a lower section connected to the main body. The invention also comprises an inner adjusting body with a top and a bottom wherein a mandrel is connected to the bottom, the mandrel configured to actuate a holding body upon actuation of the inner adjusting body, the inner adjusting body positioned inside the upper section, the main body and the lower section and an actuator connected to the upper section, the actuator configured to actuate the inner adjusting body.

Abstract: An apparatus, transfer cask, system, and method for defueling a nuclear reactor and transferring spent nuclear fuel from a spent nuclear fuel to a storage cask for long terms storage. In one aspect, the invention is an apparatus for use in transferring a canister of spent nuclear fuel from a transfer cask to a storage cask, the apparatus comprising a radiation absorbing shield surrounding a portion of a hole through which the canister can pass; means for securing the apparatus to the top surface of the storage cask; means for securing the bottom surface of the transfer cask to the apparatus; wherein the transfer cask securing means and the storage cask securing means are positioned on the apparatus so that when the apparatus is secured to both the transfer cask and the storage cask, the cavity of the transfer cask, the hole, and the cavity of the storage cask are substantially aligned; and means for moving the bottom lid in a horizontal direction once the bottom lid is unfastened from the bottom surface.

Abstract: An apparatus, transfer cask, system, and method for defueling a nuclear reactor and transferring spent nuclear fuel from a spent nuclear fuel pool to a storage cask for long terms storage. In one aspect, the invention is an apparatus for use in transferring a canister of spent nuclear fuel from a transfer cask to a storage cask, the apparatus comprising a radiation absorbing shield surrounding a portion of a hole through which the canister can pass; means for securing the apparatus to the top surface of the storage cask; means for securing the bottom surface of the transfer cask to the apparatus; wherein the transfer cask securing means and the storage cask securing means are positioned on the apparatus so that when the apparatus is secured to both the transfer cask and the storage cask.

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sits atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190).

Abstract: The diameter of a segment of a peripheral rod (2) in a fuel assembly is measured between two successive spacer grids (3). A measuring tool (14) is positioned at a level situated between the two successive spacer grids (3), the tool comprising two measuring fingers (18) that are free to move relative to each other in a first horizontal direction (X) and that are urged towards each other by resilient return means, and that extend in a second horizontal direction (Y) perpendicular to the first horizontal direction (X). The measuring fingers (18) are moved in the second horizontal direction (Y) towards a rod (2) so as to put two contact pieces of the measuring fingers (18) into contact with two zones of the rod segment.

Abstract: Method of fabricating a fuel rod, comprising providing an effective amount of a metal oxide in the fuel rod to generate steam and mitigate the tendency for secondary hydriding. Fuel rods fabricated according to the method of the invention are also provided.

Abstract: Method of fabricating a fuel rod, comprising providing an effective amount of a metal oxide in the fuel rod to generate steam and mitigate the tendency for secondary hydriding. Fuel rods fabricated according to the method of the invention are also provided.

Abstract: An apparatus and method for maximizing the radiation shielding for spent nuclear fuel during cask transfer procedures. In one aspect, the method comprises submersing an apparatus having a jacket and a cavity for receiving spent nuclear fuel into a pool, wherein the jacket is empty and hermetically sealed; placing spent nuclear fuel into the cavity of the apparatus; lifting the apparatus from the pool; placing the apparatus in a staging area; filling the jacket with neutron absorbing liquid; draining the pool water from the cavity; and lifting the apparatus from the staging area.

Abstract: The installation is designed for loading a nuclear fuel assembly that comprises a skeleton structure defining parallel locations for receiving fuel rods distributed in sheets. The installation comprises a horizontal bench (22) for receiving a skeleton structure, a magazine (16) for receiving rods for loading in a disposition that corresponds to that of the rods in the assembly, and a pulling bench (26) having a block of pulling or pushing elements enabling a plurality of rods to be slid simultaneously from the magazine into the skeleton structure. The bench makes it possible for a set of clamps from a plurality of sets each corresponding to a particular type of assembly to be fixed removably thereto by quick coupling and uncoupling means closed by actuators. The pulling bench (26) receives one out of a plurality of pulling element selector blocks, each block having a disposition of active pulling elements corresponding to a particular distribution of rods.

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sits atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190).

Abstract: The present invention relates to a zirconium alloy having excellent corrosion resistance and mechanical properties and a method for preparing a nuclear fuel cladding tube by zirconium alloy. More particulary, the present invention is directed to a zirconium alloy comprising Zr-aNb-bSn-cFe-dCr-eCu (a=0.05-0.4 wt %, b=0.3-0.7 wt %, c=0.1-0.4 wt %, d=0-0.2 wt % and e=0.01-0.2 wt %, provided that Nb+Sn=0.35-1.0 wt %), and to a method for preparing a zirconium alloy nuclear fuel cladding tube, comprising melting a metal mixture comprising of the zirconium and alloying elements to obtain ingot, forging the ingot at &bgr; phase range, &bgr;-quenching the forged ingot at 1015-1075° C., hot-working the quenched ingot at 600-650° C., cold-working the hot-worked ingot in three to five passes, with intermediate vacuum annealing and final vacuum annealing the worked ingot at 460-540° C.

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sits atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190).

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sets atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190). In a second embodiment the integrated head assembly (1100) includes a missile shield (1400) and CRDM cooling system (1600) that permits access to individual CRDMs from above.

Abstract: An integrated head assembly (100) is disclosed for a nuclear reactor. The preferred integrated head assembly includes a lift assembly (150) that supports the reactor vessel closure head (90) and integrated head assembly for removal, a separate support structure (202) supported by a ring beam (151) that sits atop the reactor vessel closure head, a shroud assembly (200), a seismic support system (300), a baffle assembly (500), a missile shield (400), and a CRDM cooling system. The CRDM cooling system draws cooling air into the baffle assembly, downwardly past the CRDMs (96), outwardly to upright air ducts (600), upwardly to an upper plenum (680), and out of the assembly through the air fans (190).

Abstract: An upper guide structure for simplification of a refueling procedure in a nuclear power plant includes an upper guide cylinder inserted in an upper end portion of a core support barrel installed inside a nuclear reactor vessel to guide a control rod assembly, a support plate installed at a lower end of the upper guide cylinder and having a plurality of first control rod insertion holes formed therein, hollow control rod assembly upper guide tubes respectively installed in the first control rod insertion holes, and a nuclear fuel alignment plate installed at lower ends of the control rod assembly upper guide tubes and including a plurality of second control rod insertion holes formed at positions corresponding to the control rod assembly upper guide tubes, each of the second control rod insertion holes having an inner diameter which increases to an lower end thereof so that the nuclear fuel assembly guide rod is inserted even when a position alignment error of the nuclear fuel assembly is great, and first cool

Abstract: The assembly apparatus (14) comprises a frame (16) for supporting the straps (2) of the first set of straps in mutually parallel positions, clamping and engagement means (30) for clamping on each of the straps (3) of a second set of straps in succession and for engaging them with the straps (2) of the first set in position in the support frame (16), and at least one comb (29) that is movable between a disengaged position and a position in which it engages each of the straps (2) of the first set. The support frame is secured to a fixed structure (15), the clamping and engagement means (30) and the comb (29) being mounted to move in respective planes perpendicular to the straps (2) of the first set on a carriage (22) which is itself mounted to move in a direction parallel to the longitudinal direction of the straps (2) of the first set, and the clamping means (30) comprise two jaws (30a, 30b) having studs for retracting the springs of the strap (3) of the second set of straps by pressing against them.

Abstract: Method of fabricating a fuel rod, comprising providing an effective amount of a metal oxide in the fuel rod to generate steam and mitigate the tendency for secondary hydriding. Fuel rods fabricated according to the method of the invention are also provided.

Abstract: Method of fabricating a fuel rod, comprising providing an effective amount of a metal oxide in the fuel rod to generate steam and mitigate the tendency for secondary hydriding. Fuel rods fabricated according to the method of the invention are also provided.

Abstract: A fuel rod extracting machine which can extract the fuel rods one by one from a Korean type 17×17 Light Water Reactor fuel assembly comprises a multi-functional rotary head including a camera for measuring the positions of the fuel rods and securing nuts being fastened on the bottom end piece of fuel assembly, an impact wrench for unfastening the securing nuts, and a gripper for gripping and extracting the fuel rods one by one. All of these are installed on a single rotary disc, which is driven by a tool rotating motor, at intervals of 90 degrees. To improve the reliability and safety in using the multi-functional rotary head, a load cell and a remote compliance center are installed at the rear of the gripper. The load cell monitors a state of insertion of the fuel rod into a collet and measures a fuel rod extracting force. The remote compliance center provides the smooth insertion of the fuel rod onto the collet, even though there exists a small misalignment between them.

Abstract: A socket is mounted to each end plate of a reactor core spray sparger, and a support having the structure of supporting said sockets is mounted by pushing against said sockets mounted to end plates facing each other with a jack. By this, the end plates of a reactor core spray sparger can be reinforced with ease.

Abstract: A preventive maintenance method and apparatus for a structural member in a reactor pressure vessel according to the present invention reduce a tensile residual stress on a surface of the structural member by impinging a water jet from a nozzle onto a plane surface of a deflector to thereby change direction of flow of the water jet, and impinging the water jet after being deflected onto the surface of the structural member. This method and apparatus are applicable to a narrow space portion, and can improve a residual stress on the surface of the structural member and can also prevent damage such as stress corrosion cracking.

Abstract: A tool kit for adjusting the angular orientation of water rods about respective axes in a nuclear fuel bundle includes a washer wrench, socket, orientator wrenches, orientator gauges and an orientator cap. The washer wrench has opposed jaws having parallel surfaces and reliefs at junctures between the surfaces and the base of the jaws to inhibit rounding off corners of tie bars connected to the water rods. The socket has a corresponding D-shaped recess as the tie bar ends to facilitate rotational adjustment thereof. Orientator wrenches have witness notches for aligning the flats of the tie bars. The orientator gauges comprise a series of gauge bodies each having a pair of axially parallel openings with stepped margins to the openings such that one opening is axially offset from the margin defining the entrance to the other opening.

Abstract: Extruded Borated Aluminum rodlets of extended length are formed to maximize neutron absorption surface area while minimizing weight. They are located in the empty cells of a new or spent fuel assembly previously used by control rods and instrumentation with a length equal to that of a fuel rod or guide tube and control the reactivity of the fuel assembly during storage and shipment of the spent fuel assembly.

Abstract: An apparatus for succesively loading solid objects (19) into a tube (27), for instance, nuclear fuel pellets into a nuclear fuel tube, includes means (17) for feeding the objects towards one, open end (29) of the tube. A reduced pressure is induced between each solid object and the tube end prior to entry of the object into the tube.

Abstract: A guide assembly is seated at the upper end of a channel for a nuclear fuel bundle. The guide assembly includes a lower guide plate with an opening corresponding in dimension to the dimension of the spacers of the fuel bundle to be inserted. The lower guide plate mounts depending locators to locate the guide apparatus on the channel. An upper guide plate spaced above the lower guide plate mounts rollers spaced from the lower guide plate a distance corresponding to the distance between the first and second spacers of the fuel bundle. The fuel bundle is lowered through the guide apparatus by engagement of the spacers with the rollers and in the channel opening to ensure the fuel bundle is guided into the channel without damage to either.

Abstract: The present invention relates to a fuel assembly (1) and a method therefor. The fuel assembly is intended for a light-water cooled nuclear reactor and comprises a first and a second locking member (9a, 9b, 10), a plurality of elongated elements (3, 3a) wherein each of the lower ends of the elongated elements is provided with an end plug (3b). The end plug (3b) is arranged guided or locked in an end plate (6) which comprises at least two adjacently disposed plug holes (6b) for receiving one end plug (3b) each. The first locking member (9a, 9b) is made in an end plug (3b) and has a concave shape and the second locking member (10) is arranged slidable in a locking hole (6c) which is adapted to extend between the two adjacently disposed plug holes (6b) and opening out into these. The second locking member (10) is made with a length exceeding the length of the locking hole (6c) and has end surfaces with shapes intended for cooperation with the concave surface of the first locking member (9a, 9b).

Abstract: A transfer device for moving a poison rod assembly between fuel cells in a nuclear fuel storage facility, where the poison rod assembly has a plurality of poison rods depending from a web. The transfer device includes a frame assembly, a poison rod assembly lifting assembly, which is moveable between an upper position and a lower position, a plurality of comb assemblies. The comb assemblies are slidably mounted on the frame so that the comb assemblies slide between an open position and a closed position as the lifting assembly moves from its lower position to its upper position.

Abstract: A method of performing maintenance on a structural member inside a reactor pressure vessel includes lowering an annular guide rail having a second lug until the guide rail rests on an upper flange of a core shroud provided inside the reactor pressure vessel, detachably mounting the second lug of the guide rail to a first lug mounted on the core shroud, positioning a discharging nozzle at a position at which compressive remaining stress is added to a surface of the core shroud by moving the discharging nozzle in a radial direction and an axial direction of the core shroud by a discharging nozzle moving apparatus mounted on a turnable revolving on the guide rail and discharging water to add compressive remaining stress to a surface of the core shroud from the discharging nozzle.