Simulation study on COPRA corium pool based on COMSOL

Abstract

BackgroundCOMSOL is considered to be an ideal approach to study the complicated physical processes in the corium pool because of its good simulation ability in multiphysics field.PurposeThis study aims to build a computational model by COMSOL to explore the turbulent flow field and phase change in the corium pool.MethodsBased on non-isothermal flow calculation module, the non-eutectic binary mixture of 20%NaNO3-80%KNO3 used in COrium Pool Research Apparatus (COPRA) experiment was simulated by using phase-change material model. The radiation heat transfer in the closed cavity at the top of corium pool was translated into the radiation heat transfer between the upper surface and the environment available as boundary condition in COMSOL.ResultsSimulation results show that in addition to the evident natural convection main flow, a mass of vortexes are existed in the corium pool, which lead to the thermal stratification of the corium pool in steady-state. Under the influence of natural convection main flow and gravity, the crust thickness along the cooling wall surface decreases with the vessel polar angle of corium pool increases.ConclusionsThe current computational model is helpful for severe accident mitigation system design.

Keywords

• corium pool
• natural convection
• thermal stratification
• comsol