Abstract: A fuel assembly design for nuclear reactors that is used in fast neutron reactor cores to provide more reliable spacing of a fuel element bundle in a fuel assembly and reduced local stress in the cladding of the fuel elements in the region where the elements are in contact with spacing elements. The fuel assembly has a top nozzle and a bottom nozzle which are connected to one another by a jacket. A bundle of rod-type fuel is elements arranged in the fuel assembly with the aid of a grid and spiral spacer elements wrapped around the cladding of each fuel element. At least the peripheral fuel elements in the bundle are provided with spacer elements in the form of thin-walled tubes with longitudinal through slots, wherein the elements have a substantially oval cross section in the regions where they are in contact with the jacket.

Abstract: The invention relates to sealing a fuel rod composite cladding tube composed of silicon carbide regardless of the fuel rod cladding design architecture (e.g., monolithic, duplex with monolithic SiC on the inside and a composite made with SiC fibers and SiC matrix on the outside) preferably with sealed SiC end plug caps, additionally sealed with an interior braze and exterior SiC final coating, thus providing a double sealed end plug barrier effective at retaining gas tightness and providing mechanical strength for the sealed end joint while providing high chemical resistance.

Abstract: Textured surface for increasing Leidenfrost temperature. The texture comprises of surface features over multiple length scales—from micro to nanoscale—wherein the features at each length scale have a size, aspect ratio, and spacing selected to increase the Leidenfrost temperature. The structure includes an array of microscale structures disposed on the surface, the structure having size, aspect ratio and spacing selected to increase Leidenfrost temperature. The microscale structures may also include nanoscale structures on their surface to create a hierarchical structure. The structures result in an increased Leidenfrost temperature.

Abstract: Textured surface for increasing Leidenfrost temperature. The texture comprises of surface features over multiple length scales—from micro to nanoscale—wherein the features at each length scale have a size, aspect ratio, and spacing selected to increase the Leidenfrost temperature. The structure includes an array of microscale structures disposed on the surface, the structure having size, aspect ratio and spacing selected to increase Leidenfrost temperature. The microscale structures may also include nanoscale structures on their surface to create a hierarchical structure. The structures result in an increased Leidenfrost temperature.

Abstract: A method and device are described to form a heat producing plant with replaceable fusion-based reaction cartridges, where the fuel is embedded in casings in the preferred embodiment, and the heat can be converted into electrical or mechanical energy. The replaceable unit consists of sheets containing individual heating elements that are addressed sequentially to trigger the heat producing reactions. A controller governs the triggering activity until all the elements are used. The resulting heat can be converted into mechanical energy using turbines and into electrical energy using the Seebeck effect. This inventive device can be used in mobile environments as well as at fixed locations where heat, mechanical power or electricity are needed.

Abstract: A tubular reactor having an insert for improving heat transfer characteristics of the tubular reactor. The insert comprises a catalyst and metal structures consecutively arranged in a lengthwise direction of the tube. The metal structures have radially expandable side walls and orifices for squeezing fluid between the metal structures and the tube wall. The radially expandable side walls form hollows between the radially expandable side walls and the tube wall of the tubular reactor. The radially expandable side walls deform responsive to the fluid pressure difference between the inside of the metal structure and the outer space between the metal structure and the tube wall thereby maintaining the gap between the orifice opening and the tube wall to adjust for tube creep.

Abstract: In a fuel bundle for a boiling water nuclear reactor comprising a plurality of fuel rods (20) secured within an array and extending between upper and lower tie plates (24, 22), and including at least one additional partial length fuel rod (20') extending from said lower tie plate (22) but terminating short of said upper tie plate (24), an improvement in the form of a removable extension rod (32) secured to said at least one additional fuel rod (20') and extending substantially to said upper tie plate (24). The removable extension rod (32) also permits variance in the reactivity of the partial length fuel rod (20') particularly in the two phase region of the bundle (10).

Abstract: A nuclear fuel element for a particle bed reactor. Concentric inner and outer porous cylinders attached at either end define an annulus therebetween that contains a fuel particle bed of nuclear fuel material. The outer porous cylinder is provided with fins that extend radially outward along its entire length. A nonporous cylinder is attached to the outer porous cylinder at either end and is positioned around the outer porous cylinder so as to be concentric therewith. Flexible fins extend radially inward form the nonporous cylinder along its entire length and contact the fins on the outer porous cylinder for conduction of heat to heat removal tubes on the outer surface of the nonporous cylinder. The heat removal tubes allow bimodal cooling of the particle bed reactor.

Abstract: A fuel assembly for use in a boiling water reactor has a multiplicity of fuel rods. In the fuel assembly, among the fuel rods located in the periphery (for example, the outermost periphery) of the cross section of the fuel assembly, the proportion of fuel rods whose enrichment in their respective lower regions are greater than the average enrichment in the lower region of the fuel assembly is less than the proportion of fuel rods whose enrichment in their respective upper regions are greater than the average enrichment in the upper region of the fuel assembly.

Abstract: A segmented fuel and moderator rod and fuel assembly for a BWR. The segmented rod has a lower fuel region and an upper moderator region for passing coolant having a void fraction of between about 0-20% through the upper portion of the BWR core which is normally undermoderated. The segmented rod displaces one or more conventional fuel rods in the fuel bundle. A method of moderating a BWR core is also disclosed.

Abstract: A method of controlling the bowing action of fuel channels used in nuclear reactor cores is disclosed. Each channel is heat treated and mounted in its control rod module with an orientation dependent on its prior heat treatment. Upon exposure to radiation, the channels will bow in a desired direction away from the control rod.