Molecular Dynamics Simulation of Xenon Diffusion in UO2 Nanocrystals

Abstract

Abstract-Diffusion of individual xenon atoms in the bulk of UO 2 nanocrystals with free surface is studied using the molecular dynamics approach. Two sets of the pair potentials of interaction of the Xe atom with uranium and oxygen ions are considered. For both sets, interstitial migration is observed, as well as the atom trapping in the uranium sites. However, the quantitative characteristics of these processes are found to be very different. The coefficients of Xe interstitial migration are obtained in the temperature range from 2400 K up to the melting point of the model crystals. The corresponding activation energies have the values of 2.5 eV and 2.2 eV depending on the interaction potentials. The results of the simulation are compared with the experimental data.