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

• The microscopic mechanisms of inhibit plutonium hydriding with different oxide overlayers were revealed. • The PuO 2 inhibits plutonium hydriding mainly due to the formation of hydroxyl groups. • The α-Pu 2 O 3 could inhibit plutonium hydriding at low hydrogen concentration conditions. • Plutonium hydriding could not be effectively resisted with α-Pu 2 O 3 when hydrogen concentration is high. 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 PuO 2 because hydrogen atoms are captured by lattice oxygen to form hydroxyl groups. In α-Pu 2 O 3 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. [ABSTRACT FROM AUTHOR]