Abstract: A nuclear fuel element having a thick walled lower section that transitions to a thinner walled upper section with the transition forming an annular interior ledge that supports the fuel pellets spaced above a bottom end plug. The space between the fuel pellets and the bottom end plug forms a gas collection plenum that assures the necessary void volume exists to maintain margin to rod internal pressure limits.

Abstract: A support grid for laterally maintaining the relative position of elongated fuel elements within a fuel assembly for use within a core of a nuclear reactor. The grid is formed in the shape of a lattice with the intersecting lattice members defining a plurality of cells, most of which respectively support the nuclear fuel elements. The remaining cells support nuclear control rod guide tubes and instrumentation thimbles. The cells supporting the nuclear fuel elements are provided with diagonally positioned springs on two, adjacent walls. The springs support the fuel elements against dimples which protrude from the opposite cell walls. The adjacent, diagonal springs in each fuel element cell are inclined in opposite directions. The walls of the cells supporting the control rod guide tubes are embossed along their height at the locations intermediate the intersection between adjoining walls with a concave notch having a curvature which conforms to the outside surface curvature of the control rod guide tubes.

Abstract: Disclosed is a grid structure for supporting fuel rods in a nuclear reactor. The grid structure is formed of a plurality of interconnected thin metal grid straps that are welded or brazed together to provide a structural network of interconnected open grid cells, similar to an "egg crate divider". The grid straps are provided at regular intervals, corresponding to the width of a grid cell, with pairs of spaced, substantially horizontal, slotted spring-like projections and a substantially X-shaped spring-like projection vertically intermediate the horizontal projections. The spring-like projections are designed to support and hold the fuel rods within the grid cells under both balanced and unbalanced forces acting on the fuel rod assembly while it is in service, surrounded by coolant in the nuclear reactor.

Abstract: An expandable top nozzle subassembly for a nuclear fuel assembly includes an upper structure having a top plate and a depending peripheral sidewall enclosure, a lower adapter plate disposed below the top plate and within the enclosure with the adapter plate and sidewall enclosure being slidably movable relative to one another so as to move the top plate toward and away from adapter plate, and a plurality of resiliently-yieldable biasing devices extending between and engaging the top plate and lower adapter plate. Interengagable structure on a lower edge of the enclosure and on a peripheral edge of the adapter plate capture and retain the adapter plate within the enclosure upon movement of the enclosure relative to the adapter plate which moves the top plate away from the adapter plate.

Abstract: A fuel pellet for a nuclear reactor fuel rod is fabricated with smooth and gently sloping surfaces having no sharp edges or areas of high stress concentration. The bearing surfaces of the fuel pellets are contoured so that the pellets are easily stacked within a fuel rod and permit pivoting action between the fuel pellets. The fuel pellets are stacked end to end in a fuel rod which is incorporated into a fuel assembly for a nuclear reactor.

Abstract: Highly orientable acicular iron particles are made by reducing an acicular ferric oxide in powder form by contacting the granular acicular ferric oxide with hydrogen in the presence of a dehydrating agent selected from calcium hydride, calcium, calcium carbide, and mixtures thereof.

Abstract: Highly orientable acicular iron particles are made by reducing an acicular ferric oxide which has been formed into a porous matrix by combining it with sodium tripolyphosphate and reducing the oxide with hydrogen in the presence of a dehydrating agent.

Abstract: Improved particles for magnetic recording are provided by coating gamma ferric oxide with a mixture of barium, strontium, lead or calcium and a trivalent iron oxide. The particles have enhanced coercivity and the coercivity is relatively unaffected by elevated temperatures.