Abstract: A nuclear fuel element is fabricated from a porous graphite block containing a plurality of open coolant passageways and a plurality of fuel chambers uniformly located therebetween. The fuel chambers are filled with nuclear fuel material and closed. The entire porous block is then impregnated with a liquid carbonizable impregnant which penetrates through the septa and into each of the fuel chambers, wherein it is cured and then carbonized in situ. The resulting carbon residue integrally binds the nuclear fuel material to the fuel chamber walls of the porous graphite block and provides excellent heat transfer from the fuel to the walls of the open passageways from which the heat is extracted by the coolant.

Abstract: A vapor generator and heat exchanger, particularly suited for use in a substantially cylindrical cavity in a pressure vessel includes high and low temperature sections of the vapor generator positioned coaxially with the annular outer section terminating a distance from the end of the central or axial section to form at the one end an annulus arranged between the central or axial section and the pressure vessel wall. A plurality of reheater or heat exchanger sections and various inlet and outlet conduits are positioned in the annulus. A heating fluid is directed first transversely over the tubes of the reheater sections, then along the tubes of the central or axial high temperature section after passing over the outer annular low temperature section.

Abstract: A system for supporting a plurality of reflective surfaces in an arrangement for reflecting the rays emitted from a source of energy and converging the reflected rays to concentrate the heating effect thereof at a receptor, whereby a plurality of pairs of long tension members extend under tension between firmly anchored support members. Reflecting elements are supported by the pairs of tension members and each of the pairs is disposed to reflect the radiation from substantially all of the reflecting elements to the receptor.

Abstract: A method of making a nuclear fuel element for a fission reactor. A solid body of an alloy of zirconium and nuclear fuel metal is exposed to hydrogen at an elevated temperature to hydride the zirconium. The hydrided alloy is exposed to oxygen at a lower temperature to form a continuous oxide layer about its exterior surface and is employed in a gastight container as a fuel element. The hydrided alloy may be exposed to oxygen at a temperature of at least about 300.degree. C. prior to its enclosure in the container, or the hydrided alloy may be enclosed in the container together with a quantity of an oxygen-providing material, such as CO.sub.2 or H.sub.2 O, sufficient to oxidize its exterior surface when the fuel element is raised to an elevated temperature.

Abstract: A nuclear fuel element loading system is described which conveys a plurality of fuel rods to longitudinal passages in fuel elements. Conveyor means successively position the fuel rods above the longitudinal passages in axial alignment therewith and adapter means guide the fuel rods from the conveyor means into the longitudinal passages. The fuel elements are vibrated to cause the fuel rods to fall into the longitudinal passages through the adapter means.

Abstract: A nuclear fuel element assembling method and apparatus is preferably operable under programmed control unit to receive fuel rods from storage, arrange them into axially aligned stacks of closely monitored length, and transfer the stacks of fuel rods to a loading device for insertion into longitudinal passages in the fuel elements. In order to handle large numbers of one or more classifications of fuel rods or other cylindrical parts, the assembling apparatus includes at least two feed troughs each formed by a pair of screw members with a movable table having a plurality of stacking troughs for alignment with the feed troughs and with a conveyor for delivering the stacks to the loading device, the fuel rods being moved along the stacking troughs upon a fluid cushion.

Abstract: Nuclear fuel rods are manufactured utilizing a graphite flour-pitch matrix formulation containing an additive. The matrix formulation has a decreased viscosity at fabrication temperatures which permits manufacture of the fuel rods with lower fabrication pressures. Also, the matrix formulation does not cause the fuel rod to adhere or bond to the fuel element during heat treatment of the fuel rod in the fuel element. The nuclear fuel rods are suitable for use in high temperature gas cooled nuclear reactors.

Abstract: In a method and apparatus for cleaning nuclear fuel elements to remove carbonized pitch residue and the like, the cleaning operation preferably being conducted within an enclosure to permit containment of the removed residue, each fuel element being introduced into the enclosure through an airlock, the end surfaces and lateral surfaces of the fuel element being cleaned and one or more longitudinal passages within the fuel element being cleaned by means of a probe unit for initially determining the configuration and position of the longitudinal passages and causing cleaning elements to be aligned with the respective longitudinal passages and extended therethrough, the flow resistance of those longitudinal passages designed for gas flow being monitored by a gauging unit, clean fuel elements being removed from the enclosure through another air-lock.

Abstract: A method and apparatus is described for the countercurrent washing of particulate solids, especially nuclear fuel particles, in a washing tower including a sequential series of washing sections each having a recirculation loop for drawing fluid from an upper portion of the washing section and introducing it adjacent a restricted opening in the bottom of the same washing section in order to control the downward flow of solids from the section, an outlet section of the washing tower being arranged beneath the lowermost washing section and including a restricted passage for regulating flow of washing fluid in the washing tower, additional fluid being introduced into the outlet section of the tower in order to minimize the flow of washing solution through the restricted passage of the outlet section.

Abstract: A nuclear fuel element and a method for making the fuel element are described. The fuel element comprises a graphite block in which elongated holes are filled with nuclear fuel. The nuclear fuel in each of the holes comprises a plurality of fuel rod segments which are, before firing, spaced from each other by a plurality of spacers. Upon firing, the spacer material gasifies, leaving unfilled gaps between the fuel rod segments.

Abstract: Particulate nuclear fuel material, particulate carbon and pitch are combined with an additive which is effective to reduce the coke yield upon carbonization to mold a green fuel body. The additive may be polystyrene, a styrene-butadiene copolymer, an aromatic hydrocarbon having a molecular weight between about 75 and 300 or a saturated hydrocarbon polymer. The green fuel body is inserted in a complementary cavity within a porous nuclear fuel element body and heated in situ to decompose the pitch and additive, leaving a relatively close-fitting fuel body in the cavity.

Abstract: A blending device is described for providing a uniform mix of particulate material. A pressurized fluid is conducted into a plenum surrounding a mixing chamber proximate the lower end thereof. An annular slit in the wall between the plenum and the mixing chamber allows the pressurized fluid to discharge through the slit for agitating particulate material contained in the mixing chamber.

Abstract: An electrical cable is described wherein an inner conductor having one or more layers of radiation resistant organic insulation extends through a metal sleeve which is larger than the insulation to leave a space capable of accommodating thermal expansion of the insulation layer or layers and which may be filled with a non-reacting gas. Also described are a method for connecting such a cable, and a radiation sensor and cable assembly incorporating such a cable.

Abstract: A method for axially shuffling fuel elements in a nuclear reactor is disclosed wherein column vacancies are created in a manner to allow substantially lateral transfer of a selected number of fuel elements from another adjacent column to a vacated column, the remaining fuel elements of the partially transferred column are removed and discarded whereby to create a new column vacancy, fresh fuel elements are added to the transferred fuel elements to establish a full new column of fuel elements and continuing such shuffling throughout the entire active core of the reactor.

Abstract: An improved prosthetic device having its exterior surface formed to provide a region of controlled porosity to promote the ingrowth of bone and/or tissue. A metal coil spring is secured to a metal substrate at a plurality of points, as by being disposed in a groove having a depth about equal to the loop diameter of the spring. Adjacent loops of the spring are preferably spaced apart from one another, and adjacent side-by-side spring sections may be interleaved with one another, with the interleaved loops being affixed to each other by common bonds at their points of junction.

Abstract: A heat exchanger is described wherein a tube bundle comprising a plurality of tubes having convolutions of different radii on a common axis is provided with at least one spacer structure for supporting the tubes in spaced relation. The spacer structure comprises a plurality of parallel bars arranged in pairs and in which semi-circular recesses are formed in abutting surfaces to accommodate the convolutions of the tubes. The bars in adjacent pairs have facing surfaces in an interfitting configuration with clearances therein sufficient to accommodate thermal expansion differences in the adjacent tubes.

Abstract: A method and apparatus is disclosed for insulating a plasma using turbulent thermal insulation for the purpose of approaching thermonuclear temperatures. It includes a hollow cylinder of a metallic hydride of predetermined size which is encapsulated by an outer metallic cylinder which seals the hollow cylinder, including the ends thereof. A mixture of deuterium and tritium gas is placed within the hollow cylinder at a pressure of about 11/2 atmospheres and auxiliary and main power supplies are sequentially applied to the cylinders to respectively form a plasma and inject an electron beam into the plasma. The thermal conductivity is reduced by the resulting electron turbulence.

Abstract: Particulate graphite having a particle size not greater than about 1500 microns is impregnated with a polymerizeable organic compound in liquid form. The impregnated particles are treated with a hot aqueous acid solution to at least begin the polymerization reaction and remove excess impregnant from the outer surface thereof. The treated particles are heated to complete the polymerization and then blended with particulate nuclear fuel. A nuclear fuel body is formed by joining the blend into a cohesive mass using a carbonaceous binder.

Abstract: A gas-cooled nuclear reactor system is described having a pressure vessel with a penetration therein for accommodating a heat exchanger. A closure system is used in which a restrainer ring is positioned between a tube sheet and the interior of the pressure vessel to restrain movement of the tube sheet toward the interior of the pressure vessel.

Abstract: Apparatus is disclosed for detecting nuclear fuel leaks within nuclear power system reactors, such as high temperature gas cooled reactors. The apparatus includes a probe assembly that is inserted into the high temperature reactor coolant gaseous stream. The probe has an aperture adapted to communicate gaseous fluid between its inside and outside surfaces and also contains an inner tube for sampling gaseous fluid present near the aperture. A high pressure supply of noncontaminated gas is provided to selectively balance the pressure of the stream being sampled to prevent gas from entering the probe through the aperture. The apparatus includes valves that are operable to cause various directional flows and pressures, which valves are located outside of the reactor walls to permit maintenance work and the like to be performed without shutting down the reactor.