Keywords:severe accident of a nuclear reactor, ex-vessel corium behavior, corium spreading behavior, visualization, volume of fluid method
The complex structure of a BWR pedestal with two sump pits and a doorway was additive-manufactured to visualize the spreading behavior of silicone oil as a simulated molten core on it in three angles. The experimental parameters are reduced scale, a viscosity of silicone oil, impingement location, and flow rate. A laser profiler acquired a time-series of silicone-flow thickness distribution. The drainage weights from two sump pits and the doorway were acquired as well. A computational multi-fluid dynamics simulation on the basis of Volume of Fluid (VOF) method reproduced the three-dimensional spreading behavior, a time-series of silicone-flow thickness distribution and drainage weights successfully.