First-principles studies of the concentration-dependent tritium diffusion in the zirconium hydrides with and without Sn impurity

Abstract

We performed first-principles calculations to study the 3H diffusion in the zirconium hydrides with or without Sn impurity. Our results show that the formation of Zr3Hx becomes preferable as the 3H concentration increases. Based on the most stable configurations of Zr3Hx (x = 0.5, 1.0, 1.5, 2.0), we studied the interstitial 3H diffusion with or without Sn impurity. The results show that the interstitial 3H diffusion becomes less probable in the hydrides with a higher 3H concentration. When introducing a substitutional Sn impurity, the diffusion barriers increase. Therefore, the substitutional Sn in the diffusion pathway hampers the 3H diffusion in Zr hydrides.