Revealing the microscopic mechanism of PuO2 and α-Pu2O3 in resisting plutonium hydrogenation via ab initio molecular dynamics simulation

Abstract The hydriding corrosion of metallic plutonium (Pu) is a crucial issue for its actual applications. The current work performs systematic ab initio molecular dynamics calculations to reveal the microscopic mechanism of Pu oxides over metallic Pu in resisting hydriding reaction. The results show that Pu hydriding is inhibited by PuO2 because hydrogen atoms are captured by lattice oxygen to form hydroxyl groups. In α-Pu2O3 the hydrogen attack could be prevented when hydrogen concentration is low because oxygen vacancy acts as a trap for hydrogen migration. Whereas, when the hydrogen concentration is high enough the hydriding corrosion could not be effectively resisted.