Pipe diffusion at dislocations in UO2

We present the results of a combination of static and dynamic simulations employing empirical potentials, investigating the structures of dislocations in UO2 and show how the dislocation core structure influences the rate of O2− and U4+ diffusion along the dislocation (i.e. pipe diffusion). In the region immediately surrounding the dislocations there is a significant reduction in the activation energies and diffusion coefficients for O2− and U4+ diffusion, however only out to a cylindrical radius of ≈20 Å from the dislocation centre. The contribution of pipe diffusion to the overall O2− and U4+ diffusion is also discussed.