Ab initio study of hydrogen related defect in ZrO2: Consequences on dry and aqueous oxidation

Zirconium alloys are used as fuel cladding in nuclear reactors, where they are subject to corrosion. In this article, based on first-principles calculations, we examine the effect of hydrogenation on the thermodynamic stability of various defects in ZrO₂ oxide in dry and aqueous environments. We found a defect complex consisting of an oxygen vacancy and a hydrogen atom, V_O-H, to be particularly stable for a wide range of Fermi levels for all the environmental conditions tested. We suggest that this V_O-H complex may be responsible for the increase in the kinetics of oxidation of zirconium alloys frequently observed in aqueous environments.