Abstract: A shock absorber system was designed to absorb the energy imparted to doors in a nuclear reactor ice condenser compartment as they swing rapidly to an open position. Each shock absorber which is installed on a wall adjacent each door is large and must absorb up to about 40,000 foot pounds of energy. The basic shock absorber component comprises foam enclosed in a synthetic fabric bag having a volume about twice the foam volume. A stainless steel knitted mesh bag of the same volume as the fabric bag, contains the fabric bag and its enclosed foam. To protect the foam and bags during construction activities at the reactor site and from the shearing action of the doors, a protective sheet metal cover is installed over the shock absorber ends and the surface to be contacted by the moving door.

Abstract: Calibration apparatus for verifying the position and orientation of transducers used in nuclear reactor vessel inspection apparatus is disclosed. A tank, filled with water, the operating inspection medium, is fitted with a movable mounting assembly adapted to securely accommodate a transducer and the mounting assembly in which it is normally secured during an inspection procedure. The tank is also provided with a slidably mounted target positioned therein at a predetermined distance from the target which is selected to avoid the distortion effects in the near field of the transducer response. The calibration apparatus can be used to check the normal transducer mounting for either perpendicularity or angular orientation by moving the tank's mounting assembly via a lead screw with which it is threadingly engaged.

Abstract: A nuclear reactor containment arrangement incorporating a permanent cavity to vessel seal in the form of a flexible quarter-circular annular steel gasket affixed to and extending between the reactor vessel seal plate and cavity wall. The seal functions to isolate the periphery of the vessel from a permanent water-tight compartment above the reactor vessel which is flooded during refueling operations to minimize the release of radiation upon exposure of the nuclear core. The seal is designed to accommodate both radial and axial expansion of the pressure vessel relative to the cavity wall occurring during reactor operation without breaking the water-tight integrity of the seal. The pressure vessel ventilation system is provided with an air exit duct at the reactor nozzle level to facilitate the circulation of air around the periphery of the vessel which would otherwise be restricted at the seal to vessel interface.

Abstract: A remote access manipulator for performing operations on equipment located in areas where human access is limited. The manipulator comprises a slave carriage located in the equipment on which the operation is to be performed, such as a nuclear steam generator, for carrying tools and inspection devices for performing operations on the equipment together with a master carriage located in a scale model of the equipment and electrically connected to the slave carriage for controlling the movement of the slave carriage. The slave carriage is capable of advancing across a surface of the equipment to position the devices which it carries. The manipulator further comprises a slave manipulator arm used to move the slave carriage into and out of the equipment on which the operation is to be performed in conjunction with a master manipulator arm located in the scale model for controlling the movement of the slave manipulator arm.

Abstract: A method for deriving, from a starting material including an element having a plurality of isotopes, derived material enriched in one isotope of the element. The starting material is deposited on a substrate at less than a critical submonatomic surface density, typically less than 10.sup.16 atoms per square centimeter. The deposit is then selectively irradiated by a laser (maser or electronic oscillator) beam with monochromatic coherent radiation resonant with the one isotope causing the material including the one isotope to escape from the substrate. The escaping enriched material is then collected. Where the element has two isotopes, one of which is to be collected, the deposit may be irradiated with radiation resonant with the other isotope and the residual material enriched in the one isotope may be evaporated from the substrate and collected.

Abstract: A nuclear core including a reflector assembly cooling arrangement utilizing a combination of forced and natural convection cooling. Forced convection cooling is achieved by using a low pressure gradient to drive coolant through the reflector assembly. Natural convection cooling of the reflector assembly is accomplished by using heat from the reflector assembly and cooling provided by core bypass coolant flow to circulate coolant by natural means through the reflector assembly.

Abstract: A method and apparatus for power generation from a recirculating superheat-reheat circuit with multiple expansion stages which alleviates complex control systems and minimizes thermal cycling of system components, particularly the reheater. The invention includes preheating cold reheat fluid from the first expansion stage prior to its entering the reheater with fluid from the evaporator or drum component.

Abstract: A lateral support device for a nuclear fuel rack vertically positioned within a walled enclosure which provides a preload to maintain effective support. The device includes a scissors-jack which is mounted so that the drive screw is vertical. Upon rotation of the drive screw the jack expands horizontally, seating a load pad against a vertical wall. The load pad is affixed to the jack by an arm having a stack of spring washers which compress between the pad and the jack, thereby applying a selected preload.

Abstract: A positionally variable mounting assembly for transducers used to interrogate a nuclear reactor vessel is disclosed. Means are provided for clamping each transducer of an array about its flange in a central restraining block. The central restraining block is, in turn, pivotally mounted in a yoke.The yoke is movable secured to bars or rails bolted to the transducer plate and, by loosening appropriate bolts, can be moved along the ways or pivoted about one of them. Further, the restraining block can be removed from the yoke and pivotally clamped in a different orientation to upstanding brackets attached to the transducer array plate, or rotated through 90.degree. and then secured again in the yoke.

Abstract: Automatic apparatus for loading a predetermined amount of nuclear fuel pellets into a nuclear fuel element to be used in a nuclear reactor. The apparatus consists of a vibratory bed capable of supporting corrugated trays containing rows of nuclear fuel pellets and arranged in alignment with the open ends of several nuclear fuel elements. A sweep mechanism is arranged above the trays and serves to sweep the rows of fuel pellets onto the vibratory bed and into the fuel element. A length detecting system, in conjunction with a pellet stopping mechanism, is also provided to assure that a predetermined amount of nuclear fuel pellets are loaded into each fuel element.

Abstract: Apparatus for baffling the flow of reactor coolant fluid into and about the core of a nuclear reactor. The apparatus includes a plurality of longitudinally aligned baffle plates with mating surfaces that allow longitudinal growth with temperature increases while alleviating both leakage through the aligned plates and stresses on the components supporting the plates.

Abstract: Hydrocarbons are formed of coal and water. The water is converted or dissociated separately into hydrogen and oxygen in a first chemical reactor by thermochemical and/or electrolytic processing. The resulting hydrogen is then reacted with the coal in a second reactor to produce the hydrocarbons. Residual carbon from the second reactor is reacted in a third reactor with oxygen derived from the first reactor to produce carbon monoxide. The carbon monoxide is reacted with residual hydrogen from the second reactor or hydrogen from the first reactor to produce additional hydrocarbons. The energy for the endothermic and/or electrolytic processing in the reactors and for auxiliary equipment of the apparatus is supplied by a very high-temperature, gas-cooled, nuclear reactor by heat interchange with the cooling gas, helium. The cooling gas operates through heat-exchange means which isolates the cooling gas from the processing apparatus.

Abstract: The content of uranium, in a solution, as extracted from uranium ore by a solution mining technique for example, is determined by measuring the intensity of selected gamma or X radiation emitted by the solution. The gamma or X radiation is preferably derived from the thorium-234 daughter of uranium 238. The radiation from the solution impinges on a scintillator after being passed successively through K-edge filter foils of an alloy of ytterbium (e.g. with tin), an alloy of lutecium (e.g. with tin), and an alloy of hafnium (e.g. with zirconium). The resulting scintillation counts of the scintillator with the filter foils are arithmetically processed so that the scintillation derived from the thorium-234 63 KeV line is isolated. This scintillation is evaluated as a measure of the uranium content. To assure that the uranium thorium conversion has reached a stable state, the measurement should be made about three months after the uranium solution is produced.

Abstract: A remote access manipulator comprises a locking mechanism capable of self-alignment for performing operations on equipment located in areas where human access is limited. The manipulator further comprises a slave carriage located in the equipment on which the operation is to be performed, such as a nuclear steam generator, for carrying tools and inspection devices for performing operations on the equipment together with a master carriage located in a scale model of the equipment and electrically connected to the slave carriage for controlling the movement of the slave carriage. The slave carriage is capable of advancing across a surface of the equipment to position the devices which it carries. The manipulator further comprises a slave manipulator arm used to move the slave carriage into and out of the equipment on which the operation is to be performed in conjunction with a master manipulator arm located in the scale model for controlling the movement of the slave manipulator arm.

Abstract: There is disclosed a method for rapid refueling of a nuclear reactor. The upper package including the head and upper internals and control rods of the reactor includes a missile shield and by engagement with the shield is moved to a refueling position in a single lifting operation exposing the core in the lower package. The fuel assemblies are then replaced. The removal of the control rods from the core with the upper package is compensated for by an increase in the concentration of neutron absorber, such as boron including B.sup.10, in the medium in which the core is immersed. Typically, the refueling can take place in a few days, at intervals of two to six months. During refueling a fraction of the assemblies are replaced. Because of the facility for rapid refueling and consequent lower time cycle for refueling, the fuel can be of low enrichment and the concentration of neutron absorber in the reactor coolant medium can be decreased.

Abstract: A core and a transition fuel assembly for a nuclear reactor having a first fuel assembly including structure for laterally spacing parallel and coextending fuel rods positioned at preselected core elevations and also having a second fuel assembly including lateral spacing structure at preselected core elevations, at least one of which is different than the elevations of the spacing structure of the first fuel assembly. The transition fuel assembly is positioned between the first and second assemblies and includes lateral spacing structure positioned at each core elevation where the first and second fuel assemblies have a spacing structure. The transition fuel assembly ensures that contact among the fuel assemblies of the core is through the spacing structures.

Abstract: Uranium ore deposits which contain certain proportions of other metals and elemental components, such as are present in redox roll front ore deposits, are selectively leached in situ by passing therethrough relatively dilute aqueous leach solutions comprising essentially from about 0.5 to 5 grams per liter of ammonium bicarbonate and from about 0.1 to 3 grams per liter of peroxide, preferably introduced as aqueous H.sub.2 O.sub.2, and sufficient ammonia to bring the solution to a pH of from about 7.4 to 9, and preferably from 7.5 to 8.5, thereafter withdrawing from the ore deposit the aqueous leach solution enriched in uranium which it preferentially extracts along with a generally lower proportion of other metals and elements as compared to their respective ratios in the ore deposit, and contacting the enriched leach solution with a strong base anion exchange material to strip the uranium from the leach solution.

Abstract: A support structure for the lattice supporting a fusible material in the annular condenser region of a nuclear reactor containment, the flexibility of which structure can be selectively adjusted in accordance with seismic or other loading requirements. The lattice is affixed to a flexible member in a manner which allows relative movement between the two components. The flexible member is affixed to a rigid support member in a manner which selectively adjusts the resiliency of the flexible member. The support member is rigidly affixed to a wall of the containment annulus, and can also be utilized to support cooling ducts.

Abstract: A lateral restraint device for nuclear fuel racks which can accommodate differential thermal expansion between the racks and a containing enclosure. The restraint includes a piston, movable within a cylinder, joined to one or more support pads which contact the wall of the enclosure. A spring is also provided within the cylinder to act upon the piston. The piston is sized to provide a predetermined clearance or opening allowing controlled liquid flow into the cylinder. The piston can be held in a given position within the cylinder with the spring compressed to facilitate installation onto the side of a fuel rack, and subsequently positioned by the expanded spring. Relatively small differential expansion loads are accommodated by the moving piston and spring, while large loads, such as those imposed by a seismic occurrence, are resisted by the hydraulic fluid within the cylinder.

Abstract: A lateral restraint and control system for a nuclear reactor core adaptable to provide an inherent decrease of core reactivity in response to abnormally high reactor coolant fluid temperatures. An electromagnet is associated with structure for radially compressing the core during normal reactor conditions. A portion of the structures forming a magnetic circuit are composed of ferromagnetic material having a curie temperature corresponding to a selected coolant fluid temperature. Upon a selected signal, or inherently upon a preselected rise in coolant temperature, the magnetic force is decreased a given amount sufficient to relieve the compression force so as to allow core radial expansion. The expanded core configuration provides a decreased reactivity, tending to shut down the nuclear reaction.