Ex-vessel molten core solidification behavior by moving particle semi-implicit method

Abstract

Development of analysis code for predicting the molten core solidification behavior during the severe accident in nuclear power plants is necessary. Although agreeable results have been achieved using existing codes such as CORFLOW and LAVA to analyze some melt spreading experiments, these codes have a common problem of versatility because they all use empirical equations such as mass flux depending on distance from wall to calculate free surface of fluid. 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. In this work, the MPS code for incompressible fluid was developed for calculating thermal field, solid-liquid phase transition, and temperature dependence of viscosity. Based on the MPS model, the FARO-L26S core melt solidification experiment was analyzed. For the leading edge position of the melt in this experiment, three-dimensional MPS simulations predicted agreeable multistage curve results with the experiment. © 2012 Atomic Energy Society of Japan. All rights reserved.