Carbon Diffusion in Uranium during Thermal Reprocessing in Vacuum

Abstract

It is shown that during annealing of uranium samples at 550–950°C in a 10^–3 Pa vacuum carbon impurity diffuses from the interior volume to the surface of the samples. The diffusion flux of carbon directed toward the surface arises as a result of the formation of uranium oxymonocarbide, which contains carbon impurity, on the surface in the presence of low oxygen partial pressure. The carbon diffusion rate in α-uranium grains depends on the crystallographic orientation of the grains, i.e., carbon diffusion in α-uranium is anisotropic.