First study of uranium self-diffusion in UO2 by SIMS.

Uranium self-di?usion coe cients were measured in UO2 single crystals through an original methodology based on the utilization of 235U as tracer and depth pro?ling by secondary ion mass spectrometry (SIMS). The values of the selfdi ?usion coe cients measured in this work, between 1498 and 1697?C, in H2 atmosphere, can be described by the following Arrhenius relation: D (cm2/s).8.54 ? 10?7exp[)4.4(eV)/kT], and are lower than those previously determined by other authors in `nearly stochiometric' UO2 in the same temperature range. ? 1998 Elsevier Science B.V. All rights reserved