Optimization of HTR fuel design to reduce fuel particle failures

In this paper, an attempt is made to formulate criteria that can be used in the redesign of HTR fuel. A simplified fuel performance model is setup to calculate the fuel particle failure probability as a function of the TRISO particle design and the particle packing fraction. These models require knowledge of the fast neutron dose, the fuel burnup level, and the fuel temperature. In this paper, a neutronic, thermal-hydraulic and burnup calculations for the PBMR 400 MWth design are used to provide the fuel performance model with the required data. It was found that the failure impact increases considerably with increasing number of particles and reactor operating temperature, but decreases with a larger buffer layer. (authors)