Modeling and Analyzing of Fuel with Missing Pellet Surface (MPS) Defect Based on Multiphysics Method

Maintaining the integrity of cladding is essential to avoiding the release of fission gas product in light water reactors. The fuel operating with a missing pellet surface (MPS) due to manufacturing defects is considered as an important cause of cladding failure. Therefore, it is of significance to establish analysis code to investigate and understand the failure mechanism in that circumstance. Based on COMSOL Multiphysics finite-element platform and CAMPUS code, this paper presents a fuel performance code with 2D cross-section geometry of a fuel pellet with cladding. First, the code is verified by predicting the performance of fuel without MPS defect compared with CAMPUS code. Then, it is used to analyze the fuel performance as a missing pellet surface (MPS) defect is considered. Finally, the behaviors of fuel with different depths of MPS defect are compared, and the behaviors of systems of UO2-Zircaloy and U3Si2-Zircaloy with MPS in the same condition are also investigated.