Abstract: A high pressure laser welding method and apparatus enables seam welding of a nuclear fuel rod at hyperbaric pressure. In an automatic process, a loaded fuel rod and an upper end plug are mated within a sealable weld box. A pressure within the weld box is controlled relative to a pressure within the fuel rod, and a laser assembly welds the seam at hyperbaric pressure. Helium flowing through a laser window nozzle during welding prevents soot contamination of the laser window glass and prevents formation of ionic plasma. The upper end plug fuel rod welding operation is thus reduced to a single step and eliminates inspection related tasks with respect to a sealed hole.

Abstract: End plugs for nuclear fuel rods are provided with a spot weld along the interior end face of the end plugs to seal any streamer openings or passages along the axis of the end plugs, thereby maintaining the fuel rods sealed at its opposite ends. The spot welds are applied by an automated laser welding system in which pallets of end plugs are supported on X-Y positioning tables below a laser movable in a vertical direction. By successively locating the end plugs in the pallet below the laser, the spot welds are formed along the axis of the end plugs and along the interior faces thereof sealing the end plugs.

Abstract: In a nuclear reactor fuel bundle assembly having a plurality of fuel rods and a non-round water rod extending between upper and lower tie plates, and having at least one fuel rod spacer located along the non-round water rod, an improvement which includes cooperating components on the fuel rod spacer and on the water rod for permitting movement of the spacer along the water rod to a desired axial location and for thereafter preventing further axial movement of the spacer in at least one of two opposite axial directions, the cooperating components including at least one spring on one of the spacer and the water rod.

Abstract: Fluoride is recovered from an aqueous ammonium fluoride and ammonium hydroxide solution by electrolyzing the solution in an electrochemical cell having an ion-exchange membrane between a catholyte chamber and an anolyte chamber whereby hydrofluoric acid is formed and the concentration of ammonium hydroxide is enriched. Part of the hydrofluoric acid can be combined with the ammonium fluoride remaining after the ammonium hydroxide had been stripped from the treated solution to produce ammonium acid fluoride.

Abstract: An apparatus for loading nuclear fuel rods through spacer grid cells of a fuel bundle includes a handle having at least one elongate clip joined thereto, and a flexible tubular sleeve joined to the clip. The clip rigidly supports the sleeve along its longitudinal axis while allowing the sleeve to unfurl perpendicularly thereto for disassembly from a fuel rod. In several embodiments of the invention, the clip may include a slot for bridging adjacent grid cells during assembly, or the clip may be removably fixedly joined to the handle for allowing easy replacement of the sleeves.

Abstract: A one-shot thermal fuse mounted directly on the casing of a centrifugal pump to prevent overheating and concentration of ammonium nitrate. The thermal fuse is screwed into a standard pipe coupling welded to a designated location on the pump casing. The thermal fuse has an electrical contact connected in the pump control circuit. A compressed spring is prevented from urging the electrical contact into an open position by a pellet of fusible material which is designed to melt at a desired threshold temperature below the temperature at which ammonium nitrate explodes. If the heat produced by the pump melts the pellet of fusible material, the spring is released, thereby opening the electrical contact and shutting off the pump. Alternatively, the temperature-sensitive element mounted on the pump casing can be a thermocouple or a temperature switch having a bimetallic element.

Abstract: A method of passivating the surface of particulate uranium oxides is disclosed comprising a process of continuously contacting uranium oxide particles with an oxygen containing and cooling counter flowing gas stream. The treatment produces a protective surface which inhibits subsequent oxygen chemisorption of the particulate uranium oxides.

Abstract: A process for controlling the oxidation reaction of oxides of uranium and fixing the ratio of oxygen to uranium in uranium oxide compounds by means of a passification process, and the stabilized uranium oxide compounds produced therefrom. The method is especially useful in the production of uranium oxide fuel for nuclear reactors.

Abstract: An improved method and means for sizing metal configuration through the application of thermal expansion and contraction of a shaping mandrel. The thermally induced changes in the shaping mandrel are produced from within the body at the mandrel.

Abstract: There is provided a nuclear fuel element having a zirconium alloy cladding tube with improved corrosion resistance. The cladding tube comprises a metallurgical gradient across the width of the tube wall wherein the tube has a more corrosion-resistant metallurgical condition at the outer circumference and a less corrosion-resistant metallurgical condition at the inner circumference. The metallurgical gradient can be generated by heating an outer circumferential portion of the tube to the high alpha or mixed alpha plus beta range while maintaining the inner surface at a lower temperature, followed by cooling of the tube.