Oxygen potential of hypo-stoichiometric Lu-doped UO2

Oxygen potentials of hypo-stoichiometric Lu-doped UO2, (U0.80Lu0.20)O2−x, were experimentally investigated by thermogravimetric analysis using H2O/H2 gas equilibria at 1173, 1273 and 1473 K. The oxygen potentials of (U,Lu)O2−x were higher than those of other forms of rare earth-doped UO2, specifically (U,Nd)O2−x, (U,Gd)O2−x, and (U,Er)O2−x. Slope analyses for plots of oxygen potential versus deviation from stoichiometry indicated that (U0.80Lu0.20)O2−x had a similar defect structure to that of the other forms of rare earth-doped UO2. A relationship between the effective ionic radii and oxygen potentials was found for the hypo-stoichiometric rare earth-doped UO2.