Abstract: An apparatus for assembling a miniaturized device includes a manipulator system including six manipulators operable to position and orient components of the miniaturized device with submicron precision and micron-level accuracy. The manipulator system includes a first plurality of motorized axes, a second plurality of manual axes, and force and torque and sensors. Each of the six manipulators includes at least one translation stage, at least one rotation stage, tooling attached to the at least one translation stage or the at least one rotation stage, and an attachment mechanism disposed at a distal end of the tooling and operable to attach at least a portion of the miniaturized device to the tooling. The apparatus also includes an optical coordinate-measuring machine (OCMM) including a machine-vision system, a laser-based distance-measuring probe, and a touch probe. The apparatus also includes an operator control system coupled to the manipulator system and the OCMM.

Abstract: A method for production of spacers to hold at least a number of elongated fuel rods (5) in a fuel unit (20) for placement in a re-actor (1) is described. The method comprises the steps of providing at least two spacers (30), to provide a set of mandrels (40) comprising a number of mandrels (42), to arrange at least two spacers (30) with one on top of the other on the set of mandrels (40), and to heat treat the spacers (30) when they are arranged on the set of mandrels (40) so that the cells (31) in the spacers (30) adapts to the mandrels (42).

Abstract: The present invention relates to a method for refurbishing an atomic fuel assembly storage rack the partitions (10) of which include a layer (14) of neutron-absorbing material between a wall (16) and a more or less rectangular piece of sheet metal (18) welded onto said wall. In this method the sheet metal is cut along each of the four sides. Once the short sides of sheet metal (18) have been cut by cutting the welding spots or by cutting it into sections the long sides are cut using a cutting head (20) that includes one to four blade-blade support assemblies (22) or one to four blades. Each blade (24) and blade support (26) is either fixed or movable.

Abstract: A method of assembling a fuel assembly is presented so as to reduce radiation exposure to the assembly workers and to simplify the assembly procedure. Sleeves are pre-attached to an upper nozzle, and the guide pipes are inserted into respective grid cells through the sleeves of the upper nozzle and through the sleeves of the grids. The guide pipes are fixed in place to the sleeves of the upper nozzle and of the grids by bulging. There is no welding step necessary to join any of the assembly components while the assembly is in a semi-assembled condition. Therefore, the method is simple and efficient, and reduces the risk of radiation exposure to the assembly workers.

Abstract: An apparatus is presented for removing the keys smoothly and reliably from support grids of a fuel assembly. The apparatus performs the task of removing the keys, which had been inserted into the grid through the opening sections of the grid, and enables mechanization and automation of the key removal operation. The apparatus has a robotic arm including a pair of parallel grid support members freely movably disposed at the end of the robotic arm for clamping onto the side edges of the grid. The apparatus further includes a key rotation device disposed on the support arm for engaging with and rotating the keys; a key moving device disposed on the grid support members so as to hold the keys and move the keys in the direction of the key axis.

Abstract: A key member, a method for insertion and/or removal of the fuel rods in a nuclear fuel assembly using the key member and a method of disassembling the nuclear fuel assembly using the same key member are disclosed. The key member has first projections and second projections formed on the opposite faces of an elongated key body. In the insertion or removal of the fuel rods or in the disassembling the nuclear fuel assembly, the key member is inserted into the grid and rotated to bring the first projections and the second projections into engagement with the straps of the grids and the springs on the straps to thereby the springs are deflected in a direction away from the dimples opposing to the springs. In this situation, the insertion and removal of the fuel rods can be carried out.

Abstract: A method for deforming, splitting and chopping of contaminated, or potentially contaminated, heat exchanger tubes into short tubes segments that easily may transported to an off-site location for decontamination or disposal. The method has particular utility in dismantling potentially contaminated tubes from a tube bundle that is part of a condenser for a BWR or PWR nuclear power plant. The method involves first gripping and deforming the exterior periphery of a potentially contaminated tube with opposed transverse forces sufficient to travel the tube longitudinally out of the tubesheets in a deformed condition, and then splitting the deformed tube into first and second wall sections which are chopped into short length wall segments. The deformation preferably flattens the tube so that the short wall segments are substantially planar, with exposed inner and outer surfaces.

Abstract: In a brain irradiating system a large number of Cobalt 60 radiation sources are carried in ports in a heavy primary shield. After the normal ten year useful life of such radiation sources, they are often difficult to remove because due to corrosion, etc, the aluminum source holders become fused in their ports. The apparatus herein includes a hollow collet which grasps the head of the source holder surrounded by and, preferably, splined to a mechanical puller which securely holds the collet around the source holder cap. Liquid nitrogen is caused to flow into the hollow collet and against the cap of the source holder, causing the aluminum source holder to shrink more than the surrounding steel of the primary shield. The source holder and the Cobalt 60 source may then be either pulled out or, if threadedly engaged with the primary shield, turned out of its port.

Abstract: A rod positioning apparatus is disclosed for positioning the end of a rod for a subsequent work operation on the rod such as ultrasonic testing of the rod end. A rod stop member receives the end of a rod advanced into a rod working position. A light emitting diode emits light through a fiber optic cable and across the area a rod end occupies when positioned in a rod stop position of the rod stop member. The end of a fiber optic cable receives light emitted across the rod stop position and directs the light to a light sensor. A control is activated when the light is not sensed on the light sensor and is activated for controlling a rod advancing and securing mechanism for stopping further advancement of the rod and securing the rod in a fixed position when the rod has advanced into the rod stop position and blocked light emitted from the light emitting diode through the fiber optic cables and onto the light sensor.

Abstract: To ensure the sealed fixing of a replacement heating rod (4) on a collar (3) for passing through the casing (1) of a pressurizer, a weld is made in a single pass by a regulated MIG process. A shaft is fixed on one end of the heating rod projecting in relation to the collar (3) and in the extension thereof. A welding device is engaged and fixed in position on the shaft, this welding device comprising a tubular support (14) and an inert-gas orbital welding torch (10) with an electrode made of fusible metal, rotatably mounted about the axis of the support (14) which coincides with the axis of the rod (4). The welding torch (10) and a device to unwind welding wire which is placed in a cabinet (6) are set into synchronous rotation during the welding, by appropriate drive means. The welding is carried out in a single pass on the entire periphery of the heating rod (4) and of the collar (3).

Abstract: An apparatus and method are provided for remotely inserting and feeding a sleeve within a selected tube to be serviced mounted in a tubesheet of a nuclear steam generator, so as to relieve reverse forces generated during the insertion and feeding of the sleeve and to reduce operator interaction. The device includes a tool having a frame, at least one gripper unit having gripping fingers which extend from a top plate of the tool for detachably suspending the frame from a tube in close proximity to the selected tube. The gripper unit also includes a hydraulically actuated cylinder for retracting the gripping fingers toward the top plate of the tool to forcibly position the tool against the underside of the tubesheet. An advancing assembly supported by the frame is also provided for remotely inserting and feeding the sleeve into the selected tube. This advancing assembly is vibrated by way of a vibrator mounted thereon.

Abstract: A nuclear fuel element and a method of manufacturing the element. The fuel element is comprised of a metal primary container and a fuel pellet which is located inside it and which is often fragmented. The primary container is subjected to elevated pressure and temperature to deform the container such that the container conforms to the fuel pellet, that is, such that the container is in substantial contact with the surface of the pellet. This conformance eliminates clearances which permit rubbing together of fuel pellet fragments and rubbing of fuel pellet fragments against the container, thus reducing the amount of dust inside the fuel container and the amount of dust which may escape in the event of container breach. Also, as a result of the inventive method, fuel pellet fragments tend to adhere to one another to form a coherent non-fragmented mass; this reduces the tendency of a fragment to pierce the container in the event of impact.

Abstract: Each of cylindrical members composing a fuel spacer of separate cell type is formed at a edge portion thereof with a positioning notch or a positioning projection, which is located just opposite to one of fuel rod supporting projections formed on the inner surface of the cylindrical member. In manufacturing of the fuel spacer, the positioning notches or projections of the cylindrical members are engaged with the positioning projections or recesses formed on fuel spacer assembly jigs for precise and easy positioning of cylindrical members.

Abstract: An apparatus for correcting surface imperfections, especially as by a blow, on a surface of gear tooth includes a supporting device for a work gear so as to be capable of vibrating the work gear in the direction of the axis of the latter and burnishing gears which are rotatable and are capable of being brought into engaging contact with the work gear.

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: A vessel comprising a shell of large thickness, for example between 200 and 300 mm, consists of unit components symmetrical in revolution (2a, 2b, 6, 7, 8, 9, 10, 3a, 3b) and connected together by end-to-end welding. The components are made of a steel containing 2 to 2.50% of chromium, 0.9 to 1.1% of molybdenum and less than 0.15% of carbon. The welding for connecting these unit components is performed by means of an electron beam in a single pass over the entire thickness of the components, without filler metal. the invention applies particularly to the manufacture of a vessel for a pressurized-water nuclear reactor.

Abstract: In the automated production line manufacture of nuclear fuel bundle spacers, rod-supporting ferrules are cut from tubular stock, checked for length, laser cut to create predetermined features in the ferrule sidewall, formed with rod-centering stops in the ferrule sidewall, and checked for stop height dimensional accuracy. Pairs of ferrules are subassembled with a captive spring and assembled into a spacer assembly fixture together with other spacer parts. The fixtured spacer parts are conjoined by laser welding to create a structurally rigid spacer. The various production line operating stations are served by separate controllers linked to a central computer for production status reporting, parts traceability, and overall control purposes.

Abstract: The invention is directed to an apparatus for pulling a plurality of fuel ds out of a fuel element structure and has a gripping device which is capable of clamping the fuel rods. To reliably pull the fuel rods from an irradiated nuclear reactor fuel element, the apparatus includes an upper guide rod and a lower tension rod which lie horizontally and are arranged one above the other. The rods extend through a plurality of clamping plates in a direction perpendicular to the latter. The clamping plates are mounted so as to be parallel to each other and spacers are arranged between each two mutually adjacent ones of the clamping plates. The spacers are arranged on both rods with the width of the spacers on the lower rod beign slightly less than the diameter of a fuel rod. The clamping plates are pressable together by means of a tensioning device. The apparatus of the invention enables the gripping device to be placed on the fuel element in a simple manner.

Abstract: An apparatus and method for remotely inserting and positioning a sleeve-loaded mandrel within a damaged tube mounted in the tubesheet of a nuclear steam generator is disclosed herein. The apparatus of the invention generally comprises a frame, a mounting mechanism for detachably and pivotally mounting the frame to the open end of one of a first tube in the tubesheet, an advancing assembly supported by the frame for remotely inserting and advancing the sleeve-loaded mandrel to a position across a damaged section of the selected tube, and a drive train for pivotally positioning the advancing assembly into alignment with the open end of the selected tube. In the preferred embodiment, the advancing means is formed from the pair of hydraulically operated grippers, one of which is reciprocably movable with respect to the other.

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: Process and device for locating the ideal screwing position of bolts of large dimensions wherein a bolt (10) is lowered under control until it engages in the tapping recess of an orifice (5), the bolt (10) is rotated in the opposite direction to screwing, the point of engagement of the threads (11) of the bolt (10) in the threads of the tapped orifice (5) is detected, screwing is started under control by the rotation of the bolt in the normal direction, successive seizures are detected during the screwing, and after each seizure the ideal screwing position is located by means of a suitable path from the center corresponding to the preceding stop previously recorded, screwing is resumed after each detection of the new ideal screwing center, and the screwing of the bolt (10) is continued at a high speed until the end of screwing is detected.

Abstract: A tool for inserting sleeve blanks in damaged steam-generator tubes of light weight capable of being manipulated by ROSA, a remotely operated service arm. ROSA permits the tool to be attached externally of the channel head of the steam generator.The tool includes a fixed gripper and a moveable gripper. The gripping member of each gripper is a flexible sheet or bladder which conforms readily to the surface being engaged. For insertion, the sleeve blank is mounted on a mandrel. The insertion is carried out by operating the grippers repeatedly through the following cycle until the sleeve blank is inserted into the damaged tube:(a) The moveable gripper is set in the lowermost position.(b) The fixed gripper is open.(c) The moveable gripper engages the sleeving assembly.(d) The moveable gripper raises the sleeving assembly to the uppermost position.(e) The sleeving assembly is engaged by the fixed gripper.(f) The moveable gripper is disengaged from the sleeving assembly.

Abstract: A method of producing a composite nuclear fuel cladding lined with a liner of high purity zirconium characterized in that a raw material of zirconium sponge disposed in a hearth cavity is irradiated with an electron beam while controlling an amount of heat per unit volume (w.sec/mm.sup.3) according to an oxygen removal rate of the raw material determined by oxygen concentration of the raw material and a target oxygen concentration of an ingot for a liner to be refined, and zircaloy cladding is lined with the liner. The hearth cavity has a preferable shape in which the ratio of the cavity surface to the cavity volume is 0.20 mm.sup.-1 or larger.

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 replacement station includes an old split-pin-assembly (OSPA) removal stand and a new split-pin-assembly (NSPA) installation stand. The removal stand includes a saw and a drill. With the guide tube to which the OSPA is secured in the removal stand, the saw severs each OSPA below the flange which engages the base of the lower counterbore in the lower guide tube (LGT) separating the OSPA into a pin fragment and a second fragment including the flange and the remainder of the split-pin with the nut threaded into it. The second fragment remains secured to the LGT after the sawing operation. The guide tube is rotated so that the drill is coaxial with the shank of the pin of the second fragment. The second fragment is separated into a third fragment including the flange and a fourth fragment including the remainder of the pin and the nut both removable from the LGT. The installation stand has NSPA blades in which the new split pins are mounted. The LGT sans the OSPA's is positioned on the installation stand.

Abstract: A marked reduction in the pressure drop of cooling liquid through a grid spacer of a nuclear fuel assembly is attained by convexly contouring the upstream (usually the lower) edges of the grid members. Preferably, they are made streamlined or semicylindrical. This can be done by first beveling and then etching them, by directing a stream of mixture of abrasive and an organic polymer against them, or by traversing an electron or laser beam along them at a power and velocity such as to cause local melting. A lesser improvement is secured by beveling alone. A still further improvement can be obtained by also tapering the downstream (usually upper) edges.

Abstract: A remotely controlled tooling apparatus is disclosed for supporting and selectively disposing a tool with respect to a workpiece illustratively taking the form of a core barrel of a nuclear reactor. Illustratively, a core barrel is of a substantially cylindrical configuration and has a plurality of flow holes disposed therethrough. The remotely controlled apparatus comprises a tool carriage, a support table carried thereby for receiving the tool, a strongback assembly for supporting and guiding the tool carriage with respect to the core barrel, and a pair of clamps affixed to the strongback assembly for engaging the core barrel for suspending the strongback assembly upon the core barrel. The tool carriage and its support table carried thereby are selectively disposed with respect to the core barrel, whereby the tool may be engaged and disengaged with and from the core barrel.