Couples were formed between pure U and U-27at%Pu, and were diffusion annealed at 750C for 25h. Composition profiles were determined by means of electron microanalysis, and were used to estimate the interdiffusion coefficients. It was found that the presence of Pu markedly increased the diffusivity at 750C above the value which was predicted on the basis of U self-diffusion studies (figure 14). The diffusivities in body-centered cubic -phase U increased with increasing Pu concentration, unlike interdiffusion in orthorhombic -phase U at lower temperatures. The diffusion data suggested that Pu had a greater intrinsic diffusivity than U at 750C.

M.C.Petri, A.G.Hins, J.E.Sanecki, M.A.Dayananda: Journal of Nuclear Materials, 1994, 211[A], 1-10