Uranium self-diffusion coefficients were measured in UO2 single crystals using an original methodology based upon the use of 235U as a tracer and depth profiling by secondary ion mass spectrometry. The values of the self-diffusion coefficients measured between 1498 and 1697C, in a H2 atmosphere, could be described by:

D (cm2/s) = 8.54 x 10-7exp[-4.4(eV)/kT]

and were lower than those previously determined by others in nearly stochiometric UO2 within the same temperature range.

First Study of Uranium Self-Diffusion in UO2 by SIMS. A.C.S.Sabioni, W.B.Ferraz, F.Millot: Journal of Nuclear Materials, 1998, 257[2], 180-4