Development of an MPS Code for Corium Behavior Analysis

Abstract

Abstract After fukushima nuclear accident in Japan, phenomenology of serious accident has been paid more and more attention. And particle methods have a natural advantage in computational simulations involving deformation and free surfaces. The moving particle semi-implicit (MPS) method as a Lagrangian method is attracting increasing attention in severe accident analysis. In this paper, we developed an MPS code for the corium behavior analysis with several additional models added: a heat transfer model for thermal conductivity and a phase change model for Solid-liquid conversion, an enthalpy-based viscosity model to realize a smooth transition of viscosity at the solid-liquid interface and a surface tension model for better simulation of surface shape. Validation of the developed simulation approach is carried out with a classical water column collapse example. The heat transfer model is validated by the example of a one-dimensional plate. The surface tension model is validated by a case of droplet oscillation. A comprehensive example of the melting of “Wood’s alloy” is carried out to verify the capacity of MPS method in the simulation of melting and expansion. The simulation results are in good agreement with the experimental results, which indicates that MPS method promises well in the field of severe accidents.