Research on diffusion behavior in oxide fuels (Joint research)

Sato, Isamu; Arima, Tatsumi*; Nishina, Masahiro*; Tanaka, Kosuke  ; Onose, Shoji ; Idemitsu, Kazuya*

As one of the important properties for fuel manufacturability and burning behavior, the diffusion behavior of actinides in oxide fuels was investigated by both the experimental and the molecular dynamics simulation (MD). Using diffusion couples consisted of an Am containing mixed oxide fuel and a UO fuel, the diffusion tests were performed. The diffusion coefficients were estimated to be 10m/s 10m/s. In addition, the difference between Pu and Am diffusion coefficients was vanishingly small. The temperature dependence of bulk diffusion coefficients of actinides in mixed oxide fuels could be evaluated by MD. An evaluation technique for the grain boundary diffusion could be established based on the coincidence site lattice theory. The practical diffusion coefficients were obtained by combining data from the experiments with those predicted from MD. The practical diffusion coefficients obtained was discussed for use of a fuel behavior analysis code.