CFD-Assisted model development for estimation of hole-ablation diameter of a pressure vessel during severe accidents

摘要: Abstract To evaluate the released radioactive materials to an environment under a nuclear severe accident, it is necessary analyze ex-vessel phenomena. The releasing diameter one of most essential parameters estimate enlarged because wall reactor vessel melts due high temperature corium flow. In this study, hole-ablation model was developed based on one-dimensional heat balance equations for molten flow, crust layer, and layer vessel, respectively. Moreover, transfer coefficient situation discharging flow obtained using computational-fluid-dynamics. As result, we proposed enhancement factor, 1.57, be multiplied by external turbulent We found out that strong effect critical thickness thicknesses layer. suggested relationship between ratio superficial velocity compared with Pilch model: mean averaged error (MAE) present 9.51%, whereas 36.13%. case low superheat where can produced, without formation predicts much larger final-hole than does.