Abstract
Many studies have been reported on diffusion coefficients of Kr and Xe in irradiated U, but the values of coefficient reported have not agreed well.
In the present report, these coefficients of diffusion are considered, using the experimental results obtained and the diffusion equations, and the factors influencing the coefficients are discussed. When the sample was heated under inert gas atmosphere, the appearent diffusion coefficient increased. For highly irradiated samples, diffusion coefficient was smaller than less irradiated samples. When the sample was heated in inert gas atmosphere, the release of gases was suddenly increased at the transformation point of samples, and the gas release by thermal cycle was also increased. It is very probable that the gas bubbles migrate as a result of the surface diffusion of the matrix atoms.
