Hydrogen diffusion in plutonium hydrides from first principles

Abstract The hydrogenation of metallic plutonium (Pu) is a crucial issue for its actual applications. In-depth scientific understanding of the hydriding corrosion process of Pu requires established values of rates and associated microscopic mechanism of hydrogen diffusion in the reaction product plutonium hydrides. Therefore, in this work we investigate the hydrogen diffusion in the stoichiometric plutonium dihydride and the non-stoichiometric one that contains tetrahedral hydrogen vacancies from first principles. Our results reveal the microscopic dynamical behavior of hydrogen in these compounds and indicate that the dominant diffusion mechanism greatly depends on the temperature and composition.