INVESTIGATION ON EX-VESSEL CORIUM SPREADING PROCESS WITH INCOMPRESSIBLE SMOOTHED PARTICLE HYDRODYNAMICS METHOD

抄録

In the severe accident of PWR nuclear power plants, one of the mitigation measures for core melting accidents is Ex-Vessel Retention (EVR) that the core catcher will hold the entire mass of corium coming from the reactor and the corium can be cooled during the spreading. The study of ex-vessel corium spreading is of great significance for the application of EVR. The present paper aims to investigate on ex-vessel corium spreading process with an enhanced implicit viscosity Incompressible Smoothed Particle Hydrodynamics (ISPH) method that is especially suitable for simulating the free-surface flow with solid-liquid phase change problem. The enthalpy-based heat transfer model is added in the corrector step. Implicit viscosity algorithm is used to eliminate the time step limitation of highly viscosity in the solidification interval. The numerical simulation of the KATS15 simulant materials spreading test was carried out to check the validity of the developed model. The results show that the developed method can accurately predict the 3D corium spreading process, and is of great engineering application value and scientific significance for determining the success criteria of the corium spreading and optimizing the design of the core catcher.