The diffusion properties of He and Xe in UO2 were investigated, using densityfunctional

calculations employing the projector augmented wave method and the

generalized gradient approximation. The migration energies corresponding to both

interstitial and vacancy-assisted mechanisms were calculated and the results for the

two noble gas atoms were compared with each other. It was suggested that He

likely diffuses by hopping through a single vacancy with computed low migration

energies smaller than 0.79eV and its diffusivity was much higher than that of Xe.

Xe has a quite large migration energy compared to He; the strain energy played a

key role in Xe diffusion in UO2.

First-Principles Theory for Helium and Xenon Diffusion in Uranium Dioxide.

Y.Yun, O.Eriksson, P.M.Oppeneer, H.Kim, K.Park: Journal of Nuclear Materials,

2009, 385[2], 364-7