A Mechanistic Model for UO2 Oxidation

In dry air, the oxidation of the uranium dioxide pellets can be described as a two-step process (UO2 →U4O9/U3O7 →U3O8). The principal oxidant is O2 in air. The density of U3O8 is 23% less than that of UO2, which corresponds to a 36% net volume increase of oxidized pellets. As a result, the formation of U3O8 Oxidation kinetics of spent fuel is essential to evaluate long time wholesomeness maintenance when dry storage of spent fuel be degraded leads to fuel splitting. This volume change by oxidation effects heavily on safety management of long-time storage and disposal of spent fuel and wholesomeness of fuel. In this study, We analyze oxidation kinetics of UO2 and establish a mechanistic model at 300 .deg. C, 400 .deg. C, 500 .deg. C.