First principles investigation of trapping and diffusion of fission gas in AnO2

Abstract

The trapping of fission gases in AnO2 has been investigated using density functional theory. The behavior of fission gases varies with the size in these oxides, therefore He and Xe have been considered in this work. In ThO2 and UO2, the octahedral interstitial site has been found to be more stable than oxygen vacancy, while actinide vacancy is found most stable site for He in all three oxides. For Xe, an oxygen vacancy is a more stable site than an octahedral interstitial site and actinide vacancy is the most stable site in these oxides. Our results indicate that He is much more mobile than Xe in these oxides.[copyright information to be updated in production process]