Oxygen potential of (Pu,Am,Nd)O2−x

Abstract

The oxygen potentials of (Pu0.81Am0.08Nd0.11)O2−x were experimentally investigated by thermogravimetric analysis with H2O/H2 and CO2/H2 gas equilibriums at 1123 K, 1273 K and 1423 K. The oxygen potentials of (Pu0.81Am0.08Nd0.11)O2−x were extremely high above −200 kJ/mol near the maximum oxygen-to-metal ratio. From their high point, the oxygen potentials decreased monotonically with decreasing oxygen-to-metal ratio until the decreases of the oxygen potentials became very small before decreasing sharply again. The profiles of oxygen potentials of (Pu0.81Am0.08Nd0.11)O2−x were almost the same as those of (Pu0.91Am0.09)O2−x, whereas the oxygen potentials of (Pu0.81Am0.08Nd0.11)O2−x were higher by approximately 100 kJ/mol than those of (Pu0.91Am0.09)O2−x as a function of mean Am and Pu valences. Results were compared with those of related oxides and discussed from the viewpoint of the effects of Nd addition on the oxygen potentials.