An investigation was made of vacancy-assisted diffusion of Xe in uranium dioxide

by calculating the incorporation, binding and migration energies. All of the energy

values were obtained by using density functional theory within the generalized

gradient approximation, and the projector augmented wave method. With regard to

spin-polarization effects, it was found that the computed migration energy was

reduced and agreed well with experimental data, as compared with that obtained

using non-magnetic calculations. It was also found that an oxygen vacancy lowered

the migration energy of a uranium vacancy by about 1eV; thus enhancing the

effective movement of vacancy clusters consisting of both uranium and oxygen

vacancies. The strain energy of Xe was large enough to contribute to the clustering

of vacancies; making it the driving force for the vacancy-assisted diffusion of Xe in

UO2. All of the calculated results suggested that the trivacancy was a major

diffusion pathway for Xe in UO2.

Atomic Diffusion Mechanism of Xe in UO2. Y.Yun, H.Kim, H.Kim, K.Park:

Journal of Nuclear Materials, 2008, 378[1], 40-4