GB1431852A - Nuclear fuel and/or fertile elements and operation of a nuclear reac-or - Google Patents

Abstract

1431852 Nuclear fuel KERNFORSCHUNGSANLAGE JULICH GmbH 2 April 1973 [1 April 1972] 15715/73 Heading G6C Nuclear fuel and/or fertile material comprises coated particles of a mixture of a fissile or fertile metal oxide and a fissile or fertile metal carbide, for example mixtures of oxides and carbides of U, U-Th, or U-Pu. The proportion of carbide in the mixture (e.g. 3-20%) is such that during burn-up sufficient carbide remains to react with the oxygen produced from the oxide. The invention reduces the disadvantageous formation of CO by reaction of this oxygen with the carbon in the particle coating, which may be pyrolytic carbon and/or silicon carbide. The fuel may be made by hydrolysing and peptizing a nuclear fuel oxide to form a sol, mixing the sol with carbon black, forming spherical gel particles, sintering in a reducing atmosphere, and then coating the particles. Alternatively, the oxide powder may be mixed with powdered carbon or graphite and a binder, e.g. aluminium stearate, and formed into spherical particles which are sintered and coated. A layer containing oxide but no carbide may be provided between the core and the coating. Fuel elements may be formed by introducing the particles into a metal or graphite casing or into a graphite matrix, and are suitable for use in a high temperature or fast breeder reactor.