Jianguo Yu1 Chao Jiang1 Yongfeng Zhang1

1, Idaho National Laboratory, Idaho Falls, Idaho, United States

The presence of hydrogen (H) can detrimentally affect the mechanical properties of many metals and alloys. To mitigate these detrimental effects requires fundamental understanding of the thermodynamics and kinetics governing H pickup and hydride formation. In this work, we focus on H diffusion in Zr-based alloys by studying the effects of alloying elements, vacancy and stress, factors that have been shown to strongly affect H pickup and hydride formation in nuclear fuel claddings. Parameterized by DFT calculations, a recently developed accelerated kinetic Monte Carlo method is used for the study. It is found that for the alloys considered here, H diffusivity depends weakly on composition, with negligible effect at high temperatures. In contrast, H diffusivity is affected by stress strongly. In addition, H diffusivity is impeded under relative high vacancy concentration.