MPS simulation of spreading behavior of molten material

Abstract

Spreading behavior with solidification is important phenomenon for the assessment of containment integrity and managing the severe accident in nuclear power plants. Existing codes such as CORFLOW use empirical equations for analyzing spreading behavior. Moving particle semi-implicit (MPS) method which calculates free surface without empirical equations is suitable for analyzing the solidification behavior of fluid with large deformation. MPS calculation models have been developed for the spreading analysis and deal with calculating thermal field, buoyancy, solid-liquid phase transition and temperature dependency of viscosity. The code was improved to calculate radiation heat transfer in three dimensions and high viscosity materials, and to control numerical instability. The FARO L26S and ECOKATS-V1 experiments were analyzed and showed good agreements with the experimental results in terms of final position of melt spread. Water Spreading Test by Theofanous and SPREAD test using stainless steel melt, were analyzed and compared with the results by SAMPSON code. Both analyses agreed with the experiments. The MPS method will be useful for computer experiments with various physical property of corium. It is expected to improve severe accident analysis code.