Oxygen chemical diffusion in hypo-stoichiometric MOX

Kinetics of the oxygen-to-metal ratio change in (U0.8Pu0.2)O2−x and (U0.7Pu0.3)O2−x was evaluated in the temperature range of 1523–1623 K using a thermo-gravimetric technique. The oxygen chemical diffusion coefficients were decided as a function of temperature from the kinetics of the reduction process under a hypo-stoichiometric composition. The diffusion coefficient of (U0.7Pu0.3)O2−x was smaller than that of (U0.8Pu0.2)O2−x. No strong dependence was observed for the diffusion coefficient on the O/M variation of samples.