Diffusion Cationique et Croissance Cristalline à l'Interface UO2-PuO2

Interdiffusion coefficients of plutonium and uranium have been calculated from electron microprobe analysis of diffusion couples UO2 (green compact) / PuO2 (green compact) or UO2 (green compact) / UO2+PuO2 (green compact). A series of these diffusion couples was sintered at 1773, 1873 and 2023 K during 0 to 50 hours and under controlled oxygen potential (-88, -95 and -125 kcal/mol). The results show that grain-boundary diffusion predominates in the overall diffusion process, even during sintering and that lattice diffusion is very slow. The sintering process enhances the interdiffusion coefficients which are greater by one order of magnitude compared to those of polycrystalline diffusion couples