Computational model for calculating the diffusional release of volatile fission products from the fuel grain, including the effect of precursors

Computational model based on diffusion process has been developed for predicting the fraction of the rare gas fission products like: xenon, krypton from the UO2 fuel element. As a bench mark exercise result of computational model were compared with available models in the literature and the comparison is found to be satisfactory. Another computational model based on diffusion has been developed, including the effect of precursors. This model output shows that fractional release of a particular fission product is highly depend on the diffusion of its precursors. In addition, significant release of a particular fission product occurs via its precursors, even though it is having negligible diffusion coefficient. (author)