| Abstract Scope |
Containing hydrogen isotope diffusion is important for nuclear applications. Experiments consistently showed that isotope diffusion is enhanced by radiation. Despite extensive studies, the mechanism of this phenomenon remains a mystery because almost all defects created during radiation (e.g., vacancies, dislocations, and grain boundaries) trap hydrogen and therefore slow down diffusion. Interstitials may enhance diffusion by causing the material to swell, but the magnitude of the enhancement is insignificant. Using Fe-Ni-Cr austenitic stainless steels as an example, we have performed extensive molecular dynamics simulations to examine a variety of defects that can possibly form during radiation. We found that when the defects are composed of a mixture of phases, boundaries, and dislocation networks, diffusion can be significantly increased. |