It was recalled that questions remained regarding the mechanisms controlling fission-gas-driven swelling in such alloys. The results were presented here of ab initio calculations of the diffusion behavior of interstitial and vacancy point defects in α-U–Zr alloys. The formation energy and migration barrier of vacancy and interstitial defects, and the influence of Zr on these values, was obtained and compared with experimental results. The results confirmed that self-diffusion in pure α-U was via a simple vacancy mechanism, and showed anisotropic character. The calculated values of activation energy were consistent with the experimental results in the literature. For interstitial diffusion, the kick-out mechanism was found to have the smallest energy barrier. The calculations of point defects, and later Xe, in U–Zr alloys will provide a foundation for computational modelling of fission gas bubble nucleation and growth.

First-Principles Study of Diffusion of Interstitial and Vacancy in α U–Zr. G.Y.Huang, B.D.Wirth: Journal of Physics - Condensed Matter, 2011, 23[20], 205402