Water vapor oxidation of SiC layer in surrogate TRISO fuel particles

摘要: Abstract Under accidental conditions for high temperature gas-cooled reactors (HTGR), the SiC layer in tri-structural-isotropic (TRISO) fuel particles can be exposed to water vapor. In this study, oxidation behaviors of surrogate TRISO were investigated a He-20 vol% vapor mixed atmosphere at temperatures up 1600 °C. The growth crystalline oxide passivation with cracks and pores followed parabolic law time, where maximum was 2.3 μm at surface under became flattened increasing temperature, as function silica viscosity diffusion path Volatilization analyzed using mechanistic model that an inert gas oxidizing atmospheres could influence magnitude volatilization. fracture load strength oxidized thinned numerically estimated decrease from 2.27 1.69 N 317 299 MPa, respectively, thickness 35 32 μm. This prediction indicates should retain fission products. Additionally, mechanical integrity each particle after evaluated. results work provide important data safety analysis scenarios HTGRs.