Effect of fission Xe on diffusion of oxygen and uranium in UO₂: a molecular dynamics study

We have investigated the effect of fission Xe on diffusion of oxygen and uranium in UO₂. Survey of trapping and solution of Xe have been presented. Incorporation and solution energies of Xe for various solution sites have been calculated by Mott-Littleton approach. Results suggest that the most stable trapping site for Xe depends on stoichiometry regions. The effect on diffusion of oxygen and uranium introduced by Xe has been estimated by classical molecular dynamics simulations. It is found that Xe atoms in any trapping site raise the values of oxygen diffusion coefficients and depress activation energies. Besides, the effect introduced by Xe decreases with an increase in trapping site size. (author)