Abstract: A method of producing a nuclear fuel product includes the steps of providing a core comprising aluminium and low-enriched uranium; and sealing said core in a cladding. The low-enriched uranium has a proportion of U235 below 20 wt %. The step of providing the core including melting low-enriched uranium and aluminium in a furnace to form a melt of uranium-aluminium alloy, producing a powder from the melt of uranium-aluminium alloy, and cold-spraying the powder on a surface of the cladding.

Abstract: A method of producing a nuclear fuel product is provided. The method includes the steps of providing a core comprising aluminum and low-enriched uranium; and sealing said core in a cladding. The low-enriched uranium has a proportion of U235 below 20 wt %. The core includes more than 80 wt % of a mixture of UAl3 phase and UAl4 phase, and the mixture has a weight fraction of UAl3 phase higher than or equal to 50%, or the core includes more than 50 wt % of UAl2 phase. The core has a low-enriched uranium loading higher than 3.0 gU/cm3. The core includes less than 10 wt % in total of one or several material(s) taken from the list consisting of aluminum phase and aluminum compounds other than UAl2 phase, than UAl3 phase, and than UAl4 phase. A corresponding nuclear fuel product is also provided.

Abstract: A metal particulate fuel system is described. The metal fuel system may include particulate metal fuel for use in nuclear reactors. The particulate metal fuel may include a plurality of particles of at least one enriched alloy where the particles are compacted into a fuel column. The metal particulate fuel system may also include a cladding and/or a gas-filled plenum.

Abstract: The present invention relates to nuclear fuel compositions including triuranium disilicide. The triuranium disilicide includes a uranium component which includes uranium-235. The uranium-235 is present in an amount such that it constitutes from about 0.7% to about 5% by weight based on the total weight of the uranium component of the triuranium disilicide. The nuclear fuel compositions of the present invention are particularly useful in light water reactors.

Abstract: The nuclear reactor comprises a lower stopper sealingly fixed to a lower end of a tubular casing of the pencil that comprises a part which is internal to the casing successively comprising a first cylindrical section having a diameter which is substantially equal to the inner diameter of the tubular casing; a second cylindrical section whose diameter is smaller than the inner diameter of the tubular casing and a third cylindrical section whose inner diameter is smaller than the inner diameter of the tubular casing and greater than the diameter of the second cylindrical section such that 1-2 tenths of a millimetre radial play is created in the gas passable between the outer surface of the third section and the inner surface of the casing.

Abstract: A nuclear fuel element including a uranium-molybdenum alloy that provides an enhanced reactivity in research, test and radioisotope production nuclear reactors. In this uranium-molybdenum alloy, the uranium is enriched in the isotope 235-U, while the molybdenum is depleted in the isotope 95-Mo. The thus obtained enhanced reactivity provides, depending on the exact use of the fuel element, a requirement for less uranium in the fuel and the use of the fuel elements during a longer period in the reactor.

Abstract: A method for providing a nuclear fuel includes forming a uranium-molybdenum alloy that provides an enhanced reactivity in research, test and radioisotope production nuclear reactors. In this uranium-molybdenum alloy, the uranium is enriched in the isotope 235-U, while the molybdenum is depleted in the isotope 95-Mo. The thus obtained enhanced reactivity can have at least two advantages, depending on the exact use of the fuel element: a requirement for less uranium in the fuel and the use of the fuel elements during a longer period in the reactor.

Abstract: A method for providing a nuclear fuel includes forming a uranium-molybdenum alloy that provides an enhanced reactivity in research, test and radioisotope production nuclear reactors. In this uranium-molybdenum alloy, the uranium is enriched in the isotope 235-U, while the molybdenum is depleted in the isotope 95-Mo. The thus obtained enhanced reactivity can have at least two advantages, depending on the exact use of the fuel element: a requirement for less uranium in the fuel and the use of the fuel elements during a longer period in the reactor.

Abstract: A nuclear fuel based on UO.sub.2, ThO.sub.2 and/or PuO.sub.2 having improved retention properties for fission products. The fuel comprises a metal such as Cr or Mo able to trap oxygen in order to form an oxide having a free formation enthalpy equal to or below that of the superstoichiometric oxide or oxides (U, Th)O.sub.2+x and/or (U, Pu)O.sub.2+x (O<x.ltoreq.0.01). Thus, it is possible to trap oxygen atoms released during the fission of U, Th and/or Pu. This leads to an increase in the retention level of the fission products and a possibility of obtaining a high burn-up of nuclear fuel elements.

Abstract: A method and an apparatus for producing microspherical ceramic particles such as particulate ceramic fuels for use in nuclear reactors. To produce gel particles by performing microwave heating on the small droplets of a stock solution or sol that contains uranium and other elements for nuclear reactor fuels, the small droplets are allowed to fall down through a cavity resonator using microwaves having an engineering frequency of 2.45 GHz and a quartz rod is inserted into or withdrawn out of the resonator to adjust the resonant frequency so that it will lie within the spectrum width of the microwave frequency.

Abstract: A method of preparing active, sinterable, finely-divided plutonium oxide (PuO.sub.2) powder from plutonium metal is disclosed. The process yields plutonium fissile material which can be easily blended to form a uniformly homogeneous powder for the fabrication of high-quality light water reactor ceramic fuel pellets. Such homogeneous fuels are required to prevent hot spots from developing in a reactor using the fuel.

Abstract: A nuclear reactor core is provided with a fuel assembly which comprises channel boxes respectively separated with spaces into which control rods are arranged and a plurality of fuel rods arranged in the channel box, at least a part of the fuel rods being charged with uranium-plutonium mixture fuel and an enrichment of U-235 or a concentration of plutonium, or both being distributed in an axial direction of the fuel rods. The concentration of a burnable poison packed in the fuel rod is distributed in the axial direction of the fuel assembly. The ratio of the occupying region of a moderator of the fuel assembly is increased with respect to the fuel occupying region. The number of the fuel rods containing the burnable poison is variously changed with respect to the total number of the fuel rods and the arranging mode thereof is also varied with the concentration thereof.

Abstract: A nuclear fuel element comprising sintered pellets based on uraniferous oxide which are surrounded by a metallic sheath and permitting trapping of the fission products which appear in the course of irradiation characterized in that the pellets contain or are coated with or that the sheath is internally coated with an agent for trapping said fission products based on mixed metallic oxide comprising SiO.sub.2 and one at least of the oxides ZrO.sub.2 or CeO.sub.2.

Abstract: To increase the operating temperature of a reactor, the melting point and mechanical properties of the fuel must be increased. For an actinide-rich fuel, yttrium, lanthanum and/or rare earth elements can be added, as stabilizers, to uranium and plutonium and/or a mixture of other actinides to raise the melting point of the fuel and improve its mechanical properties. Since only about 1% of the actinide fuel may be yttrium, lanthanum, or a rare earth element, the neutron penalty is low, the reactor core size can be reduced, the fuel can be burned efficiently, reprocessing requirements are reduced, and the nuclear waste disposal volumes reduced. A further advantage occurs when yttrium, lanthanum, and/or other rare earth elements are exposed to radiation in a reactor, they produce only short half life radioisotopes, which reduce nuclear waste disposal problems through much shorter assured-isolation requirements.

Abstract: A method of inhibiting deleterious reactions between metallic fissionable fuel for nuclear reactors and stainless steel containers for housing such fuel comprising imposing an expendable body of alloying metal intermediate the fuel and container is disclosed. The disclosure also includes an improved nuclear fuel element comprising metal alloy fuel housed within stainless steel containers having a body of zirconium metal interposed between the fuel and containers.

Abstract: Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

Abstract: A flat or curved plate structure, to be used as fuel in a nuclear reactor, comprises elongated fissionable wires or strips embedded in a metallic continuous non-fissionable matrix plate. The wires or strips are made predominantly of a malleable uranium alloy, such as uranium silicide, uranium gallide or uranium germanide. The matrix plate is made predominantly of aluminum or an aluminum alloy. The wires or strips are located in a single row at the midsurface of the plate, parallel with one another and with the length dimension of the plate. The wires or strips are separated from each other, and from the surface of the plate, by sufficient thicknesses of matrix material, to provide structural integrity and effective fission product retention, under neutron irradiation. This construction makes it safely feasible to provide a high uranium density, so that the uranium enrichment with uranium 235 may be reduced below about 20%, to deter the reprocessing of the uranium for use in nuclear weapons.

Abstract: The invention discloses a metal-actinide mononitride composition with dimensional stability in extended nuclear reactor operations, with a method of operation at surface temperatures in excess of 1700.degree. C. The preferred embodiment and operating method uses a mononitride of uranium and a metal selected from the group consisting of titanium or yttrium. Parameters for determination of the metal element to stabilize the fuel are disclosed.

Abstract: A nuclear fuel includes uranium dispersed within a thorium hydride matrix. The uranium may be in the form of particles including fissile and non-fissile isotopes. Various hydrogen to thorium ratios may be included in the matrix. The matrix with the fissile dispersion may be used as a complete fuel for a metal hydride reactor or may be combined with other fuels.

Abstract: A fuel pin for a liquid metal nuclear reactor is provided. The fuel pin includes a generally cylindrical cladding member with metallic fuel material disposed therein. At least a portion of the fuel material extends radially outwardly to the inner diameter of the cladding member to promote efficient transfer of heat to the reactor coolant system. The fuel material defines at least one void space therein to facilitate swelling of the fuel material during fission.