Heat treatment of non-stoichiometric UO2-ThO2 systems

The effects were studied of the content of ThO2 (up to 20% mol.) on the kinetics of sintering UO2 of different initial composition under constant or variable partial oxygen pressure. The effects of the techniques of the preparation (mechanical mixing or coprecipitation) are negligible using the reduction atmosphere in the process of thermal treatment. Conditions of the formation of the solid solution (U,Th)Osub(2+x) were studied by X-ray structural analysis. The obtained densities of the preparations were within the region of 72.3 to 97.5% of theoretical values. (M.K.)