Volume oxidation of uranium mononitride and uranium monocarbide in the dry NOX-gaseous atmosphere

Gaseous volume oxidation (voloxidation) of uranium mononitride (UN) and uranium monocarbide (UC) was investigated in the “NOx-air” atmosphere in the temperature range 298–673 K. It was shown that UN can be converted into uranium water-soluble compounds using an alternative oxidation atmosphere based on NOX-gases. UO3 and uranyl nitrates are the main products of the reaction. Maximum degree of the UN conversion to water-soluble compounds equal to 80 % was observed at the temperature 565 K. Products of the UC conversion are uranium oxides and oxihydroxides. The observed degree of the UC conversion into water-soluble compounds was less then 20 %.

Elaboration of Uranium Monocarbide Samples for Diffusion Studies

Mixed Uranium-Plutonium Carbides are candidate fuels for 4th generation nuclear reactors. In this frame, a research program is underway at CEA (French alternative and atomic energies commission) to gather basic properties of such material to get a better understanding of in-pile behaviour. In the field of solid state physics, the measurement of transport properties and in particular diffusion coefficient requires the preparation of uranium carbide samples with very specific characteristics: very low oxygen content, mono-phased UC, high density (greater than 95% of the theoretical one), coarse microstructure, accurate samples geometry. In this paper the Process development is presented to manufacture such samples and the specific equipments which have been set up in glove-box. Characterizations of the first samples are also given.