Investigation of the fission gases behavior in meso scale: application in multiscale simulation of nuclear fuel

The behavior of fission gases such as xenon and krypton have a significant effect on the performance of nuclear fuels, their active life,  and the length of the reactor operating cycle. Two important phenomena, including the release of fission gases from the fuel rod matrix and the resulting swelling, are currently the main challenges points in studying the performance of nuclear fuels. In this regard; and in order to multiscale modelling of nuclear fuel a meso-scale fuel performance code has been developed to analyze Fission Gas Release (FGR) and swelling under steady state conditions. The obtained results are compared with experimental data for low burn up to a maximum of 6.5 MWd / tUO2, where good agreement is achieved. In fact, this code is a bridge between data from atomic-scale calculations and macroscopic scales in nuclear fuel performance codes. The developed code, has the capability to be utilized as a standalone code, or to be called as a subroutine in other nuclear fuel performance codes. It is noteworthy that the development of the code for high burnup as well as transient conditions is underway.