Abstract: A process for dissolving radioactive corrosion products from the internal surfaces of a nuclear reactor. In preparation for reactor refueling, the reactor coolant is depressurized and the temperature reduced to .about.140.degree. F. Hydrogen is purged from the system and the coolant repressurized to about 400 psi to permit operation of a reactor coolant circulating pump. A solution containing oxygen, preferably hydrogen peroxide, is injected into the reactor coolant which is then circulated through the reactor. The thus oxygenated coolant effects prompt and nearly complete release, at least 95% complete, of radioactive corrosion products, especially cobalt 58, from the reactor internal surfaces. The coolant is then circulated through a demineralizer which removes such products by ion exchange processes, at the completion of which, the reactor is opened to commence replacing fuel assemblies in the reactor.

Abstract: An ion exchanger which allows flow in both directions along a selected flow-path. A separator plate divides the exchanger tank into two chambers each of which has a flow-conduit so that flow may enter or leave from either chamber while prohibiting the resin particles from migrating from one side of the tank to the other. This ion exchanger permits a dual-directional flow-process to be practiced which results in immediate changes in the boron concentration within a nuclear reactor coolant system even if the ion-exchanger resins have not been completely equilibrated during a previous operation.

Abstract: A process for reducing the volume of spent radioactive ion exchange resins which have been used for conditioning water circulated through a nuclear reactor. The spent resins are discharged from the reactor system as radioactive wastes to a spent resin storage tank in the form of a slurry. The slurry is first vacuum dewatered to remove the free water and then the intrinsic water in the wet resin beads is removed by drying in a vacuum fluidized bed chamber utilizing superheated steam which also acts to fluidize the bed. Further drying is accomplished by spraying the partially dried resin and superheated steam through a steam injected two-fluid nozzle for further extraction of intrinsic water from the resins. The steam is discharged to a condenser and the dried resins to an evacuated disposal drum. Approximate 4:1 volume reductions from the resin-water slurry to the dried resin is obtainable by practicing the process.

Abstract: An arrangement for applying a constant load on the probe of a coordinate measurement machine to eliminate errors caused by operator hand pressure when the probe is manually moved into engagement with a part being measured. In coordinate measurement machines, a carriage movable in the Y axis direction bridges the part being measured. A probe on the carriage is movable in the X axis direction thereby permitting probe movement in any quadrant in X-Y axis directions. To eliminate measurement errors in the Y axis direction, a constant load is applied to the probe by a pair of spring motors mounted on opposite ends of the machine. These spring motors are connected by spring motor cables to the carriage. When the back cable is attached to the carriage, the applied force urges it in the +Y axis direction, and the front cable when attached, urges the probe in the -Y axis direction. To apply a constant load on the probe in the X axis direction, spring motors are mounted on opposite ends of the carriage.

Abstract: A method and apparatus are disclosed for removing nuclear fuel from a clad fuel element. The fuel element is power driven past laser beams which simultaneously cut the cladding lengthwise into at least two longitudinal pieces. The axially cut lengths of cladding are then separated, causing the nuclear fuel contained therein to drop into a receptacle for later disposition. The cut lengths of cladding comprise nuclear waste which is disposed of in a suitable manner.

Abstract: Upon the occasion of loss of coolant in a nuclear reactor as when a coolant supply or return line breaks, or both lines break, borated liquid coolant from an emergency source is supplied in an amount to absorb heat being generated in the reactor even after the control rods have been inserted. The liquid coolant flows from pressurized storage vessels outside the reactor to an internal manifold from which it is distributed to unused control rod guide thimbles in the reactor fuel assemblies. Since the guide thimbles are mounted at predetermined positions relative to heat generating fuel elements in the fuel assemblies, holes bored at selected locations in the guide thimble walls, sprays the coolant against the reactor fuel elements which continue to dissipate heat but at a reduced level.

Abstract: A nuclear reactor internals arrangement is disclosed which facilitates reactor refueling. A reactor vessel and a nuclear core is utilized in conjunction with an upper core support arrangement having means for storing withdrawn control rods therein. The upper core support mounted to the underside of the reactor vessel closure head so that upon withdrawal of the control rods into the upper core support, the closure head, the upper core support and the control rods are removed as a single unit thereby directly exposing the core for purposes of refueling.

Abstract: Apparatus for loading fuel pellets into fuel rods for a nuclear reactor including a base supporting a table having grooves therein for holding a multiplicity of pellets. Multiple fuel rods are placed in alignment with grooves in the pellet table and a guide member channels pellets from the table into the corresponding fuel rods. To effect movement of pellets inside the fuel rods without jamming, a number of electromechanical devices mounted on the base have arms connected to the lower surface of the fuel rod table which cyclically imparts a reciprocating arc motion to the table for moving the fuel pellets longitudinally of and inside the fuel rods.

Abstract: The time taken to reduce concentration of radioactive gas in the coolant of a nuclear reactor to permissible levels during refueling or the like is reduced by injecting into the reactor coolant a quantity large compared to the quantity of fission gas, of stable gas of the same atomic number as each radioactive gas. The fission gas includes both stable and radioactive isotopes, the quantity of stable isotopes being large compared to the quantity of radioactive isotopes. The stable gas added and the fission gas of each atomic number are dissolved as one gas in the reactor fluid and are purged together, the added stable gas accelerating the dissolution of the radioactive gas.

Abstract: A nuclear fuel pellet loading machine including an inclined rack mounted on a base and having parallel spaced grooves on its upper surface arranged to support fuel rods. A fuel pellet tray is adapted to be placed on a table spaced from the rack, the tray having columns of fuel pellets which are in alignment with the open ends of fuel rods located in the rack grooves. A transition plate is mounted between the fuel rod rack and the fuel pellet tray to receive and guide the pellets into the open ends of the fuel rods. The pellets are pushed into the fuel rods by a number of mechanical fingers mounted on a motor operated block which is moved along the pellet tray length by a drive screw driven by the motor. To facilitate movement of the pellets in the fuel rods the rack is mounted on a number of spaced vibrators which vibrate the fuel rods during fuel pellet insertion.

Abstract: A system is provided for determining during operation of a nuclear reactor having fluid pressure operated control rod mechanisms the exact location of a fuel assembly with a defective fuel rod. The construction of the reactor internals is simplified in a manner to facilitate the testing for defective fuel rods and to reduce the cost of producing the upper internals of the reactor.