Abstract: A method is described for electrically converting an analog signal into a digital representation in a manner that maximizes noise rejection. The digital representation is formed from a preselected number of discrete points corresponding to sampled approximations of the analog signal. In establishing the magnitudes of the respective points, digital samples of the analog signal are taken at a predetermined number of discrete coordinates along the analog signal on either side of the respective discrete points. The predetermined number of coordinates are averaged and employed as corresponding approximations for the respective discrete points in the digital representative reproduction of the analog signal. The effects of harmonics of power line frequencies associated with processing electrical equipment are minimized by sampling the discrete coordinates for a particular point over an integral number of cycles of the power line frequency.

Abstract: A direct contact thermal storage heat exchanger which utilizes the liquid-vapor phase change of a working fluid within the heat exchanger, and energy generation systems incorporating the heat exchanger. The heat exchanger is particularly useful in combination with a solar energy receiver. The heat exchanger includes an insulated pressure vessel packed with pebbles or spheres. Working fluid in the vapor phase from a solar heat source enters the unit and condenses, transferring thermal energy to the pebbles. The liquid level of working fluid about the pebbles is decreased during this mode of operation. When it is desirable to release this stored energy the liquid level is increased, and the energy is transferred to the working fluid which forms a vapor, and can be used to drive a turbine or other prime movers.

Abstract: A bearing with a lubricant reservoir that is capable of being refilled when the bearing and reservoir are submerged in a lubricant pool. The lubricant reservoir supplies lubricant to the bearing while the bearing allows a small amount of lubricant to leak passed appropriately placed seals creating a positive out flow of lubricant thereby preventing foreign material from entering the bearing.

Abstract: A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

Abstract: Apparatus for precisely positioning the seam on an end of a nuclear reactor fuel rod opposite from a welding electrode in a weld chamber. The circumferential seam is formed by abutting surfaces at the end plug-fuel tube interface, and it is important that the seam be located in an exact position relative to the welding electrode tip. This is accomplished by providing a stop member against which the fuel plug rests during the time an end plug is welded. The distances are chosen such that when the end plug is fully seated in the stop member, the electrode tip and seam will be located in optimum positions to effect the making of high quality welds. Open communication is established between the inside of the fuel rod and vacuum equipment which is used for evacuating the fuel rod of air or other gases during the welding operation through an axial passageway in the stop member.

Abstract: The neutron absorbing medium in a reactor is changed in dependence upon the loading of the reactor, or any other operating mode where the power distribution axially is to be maintained within acceptable limits, by varying the chemical shim in the coolant of the reactor. The error for effecting the change is derived by comparing the average temperature of the coolant and a reference temperature which is a programmed function of the power delivered by the turbine energized by the reactor. The reference temperature is derived by converting the turbine impulse chamber pressure into a temperature parameter. A compensated temperature error is derived from an electrical compensating network typically a PID controller. At the input of this network an electrical analog of the temperature error is impressed and its output, a compensated temperature error, is derived. The correcting command is derived from the output of a non-linear gain network.

Abstract: Radioactive emissions by reason of primary-liquid-to-secondary-liquid leakage in the steam generator of pressurized water reactor power plants are reduced by a demineralizer in the discharge from the blowdown tank and also by transmitting blowdown venting vapor to the condenser. For major failures resulting in power blackout an auxiliary turbine is provided. This turbine is connected to be energized by vapor (steam) by-passed from the main steam line. The auxiliary turbine drives the pumps which pump the cooling water for the condenser. The steam which drives the auxiliary turbine is also discharged to the condenser. The condensed water flows back into the steam generators where it is discharged through the blowdown tank.

Abstract: A safe geometry nuclear fuel powder blender of a pneumatic type having a plurality of narrow flat-walled blending chambers or "slab tanks" extending radially outward from a pneumatic spouting tube having an inlet and an outlet at bottom and top, respectively, open to each slab tank or blending chamber and contained within a cylindrical cone-bottomed shell filled with neutron-absorbing material between the blending chambers.

Abstract: An improved grid sleeve bulge tool designed for securing control rod guide tubes to sleeves brazed in a fuel assembly grid. The tool includes a cylinder having an outer diameter less than the internal diameter of the control rod guide tubes. The walls of the cylinder are cut in an axial direction along its length to provide several flexible tines or ligaments. The end of each alternate tine is equipped with a semispherical projection which extends radially outwardly from the tine surface. A ram or plunger of generally cylindrical configuration and about the same length as the cylinder is designed to fit in and move axially of the cylinder and thereby force the tined projections outwardly when the ram is pulled into the cylinder.

Abstract: A method for determining and assuring that the pressure charged in a fuel rod is retained therein after the rod is sealed by welding a hole closed in the fuel rod end plug. The fuel rod end having the open end plug therein is sealed in a plenum chamber of known volume. A helium source then charges a first chamber to a predetermined pressure, and after isolating the helium source, the first chamber is discharged into the plenum chamber and the fuel rod. If a pressure sensor in the system indicates a relatively high reading, the end plug has not permitted gas to pass into the fuel rod. A relatively low reading indicates that the fuel rod has been pressurized and the hole in the end plug is then welded shut. To verify that the end plug is properly sealed, the plenum chamber is vented to a third chamber of known volume and the system pressure is then determined. If such pressure reaches a predetermined high value, the end plug weld is defective.

Abstract: A closure head for a nuclear reactor includes a stationary outer ring integral with the reactor vessel with a first rotatable plug disposed within the stationary outer ring and supported from the stationary outer ring by a bearing assembly. A sealing system is associated with the bearing assembly to seal the annulus defined between the first rotatable plug and the stationary outer ring. The sealing system comprises tubular seal elements disposed in the annulus with load springs contacting the tubular seal elements so as to force the tubular seal elements against the annulus in a manner to seal the annulus. The sealing system also comprises a sealing fluid which is pumped through the annulus and over the tubular seal elements causing the load springs to compress thereby reducing the friction between the tubular seal elements and the rotatable components while maintaining a gas-tight seal therebetween.

Abstract: Nuclear reactor coolant pump having a tooling boom mounted on the periphery of the motor stand of the pump for transferring pump components through openings in the motor stand during performance of maintenance on the pump. The tooling boom comprises an articulated arm mounted on the periphery of the motor stand with a gripping mechanism attached to the arm at the end opposite the arm's attachment to the motor stand. The gripping mechanism is capable of having pump components firmly attached thereto so that when the articulated arm is swung in the horizontal plane, the pump components may be transferred between the inside and outside of the motor stand.

Abstract: A neutron activation probe comprises a pulsed neutron source in series with a plurality of delayed neutron detectors for measuring radioactivity in a well borehole together with a NaI (T1) counter for measuring the high energy 2.62 MeV gamma line from thorium. The neutron source emits neutrons which produce fission in uranium and thorium in the ore body and the delayed neutron detectors measure the delayed neutrons produced from such fission while the NaI (Tl) counter measures the 2.62 MeV gamma line from the undisturbed thorium in the ore body. The signal from the NaI (T1) counter is processed and subtracted from the signal from the delayed neutron detectors with the result being indicative of the amount of uranium present in the ore body.

Abstract: A method for separating isotopes in which a selected isotope of a given molecule is first excited to enhance preferential dissociative electron attachment, which facilitates the separation of the desired isotope from its natural mixture. Molecules incorporating the particular isotope of interest are selectively excited to the proper vibrational and/or electronic state by narrow line radiation to enhance preferential dissociative electron attachment. The excited molecules are then exposed to low energy electrons which dissociatively attach to the excited molecules forming stable negative ion fragments. The negative ion or neutral fragments containing the desired isotopes are then separated from the remaining mixture resulting in an enrichment of the desired isotope.

Abstract: A method for leaching mineral values from an underground ore body in situ comprises introducing an oxygen-bearing gas into a pressurized saturation-disengagement chamber located above ground of the ore body where the oxygen-bearing gas becomes dissolved in a leach solution. The leach solution with dissolved oxygen therein is then pumped into the well and through the ore body where the leach solution oxidizes the mineral values in the ore body permitting their solubilization and transport by the leach solution to a recovery well where the pregnant leach solution is pumped above ground. The pregnant leach solution is then treated to remove the mineral values therefrom. Insuring that the oxygen-bearing gas is completely dissolved in the leach solution above ground in the saturation-disengagement chamber prevents gas bubbles from being pumped into the ore formation, thereby preventing loss of injectivity.

Abstract: A grid of improved design for a nuclear reactor fuel assembly which includes a multiplicity of interleaved straps enclosed in a peripheral frame which forms a grid of egg-crate configuration. Each cell formed by the grid straps, except those containing control rod guide tubes, supports a fuel rod which is held in place by springs projecting laterally inwardly into each cell from the grid straps. The springs extend parallel to the fuel rods and are spaced at 90.degree. intervals around the rod. Further, each of two adjacent springs contact a fuel rod at two points along its length and each of the other two adjacent springs contact the fuel rod at one point thus imparting strength and flexibility to the fuel assembly containing such grids.

Abstract: An automated system for manufacturing nuclear fuel pellets for use in nuclear fuel elements of nuclear power reactors. The system comprises process components arranged vertically but not directly under each other within a single enclosure. The vertical-lateral arrangement provides for gravity flow of the product from one component to the next and for vertical removal of each component without interference with the other components. The single enclosure eliminates time consuming transfer between separate enclosures of each component while providing three-sided access to the component through glove ports.

Abstract: Positioning means for locating inspection apparatus used to volumetrically examine a nuclear reactor vessel is disclosed. The positioning means is provided with a support ring having an annular key positioned longitudinally about its periphery. Three support legs are attached to the support ring by brackets adapted to fit the annular key. In addition, the support ring also carries three guide stud bushings which are movably mounted thereon by clamps adapted to engage the support ring key. Prior to lowering the inspection apparatus into the vessel, the guide stud bushings are each moved to a point of alignment with one of three guide studs extending upwardly from the vessel. After alignment has been verified, the guide stud bushings are clamped in position.The inspection apparatus is now lowered towards its fully seated position within the vessel and is coarsely circumferentially positioned with respect thereto by the engagement of the guide studs within the guide stud bushings.

Abstract: Method for removing fuel pellets from a nuclear fuel element without damaging the fuel pellets or fuel element sheath so that both may be reused. The method comprises holding the fuel element while a high pressure stream internally pressurizes the fuel element to expand the fuel element sheath away from the fuel pellets therein so that the fuel pellets may be easily removed.

Abstract: A liquid-cooled nuclear reactor including fuel assemblies mounted within a reactor vessel having linearly movable control rods passing through control rod guide tubes into respective aligned fuel assemblies. Reactor coolant circulates through the assemblies, guide tubes and other vessel internals structures located above the assemblies and is discharged through an outlet nozzle positioned above the elevation of primary flow openings in the guide tube walls. The guide tube includes internal horizontal supports and a length limited continuous control rod guide which, in conjunction with the flow openings, alleviate detrimental coolant cross flows and frictional restraints imposed upon the control rods.