Numerical study on melt underwater spreading with MPS method

Simulation of melt underwater spreading process is important to the assessment of ex-vessel core melt (corium) risk, since such process may occur and affect corium behavior and coolability during severe accidents of a light water reactor whose cavity is flooded with water prior to the failure of the reactor pressure vessel. This study is concerned with numerical simulation of melt underwater spreading by using the Moving Particle Semi-implicit (MPS) code previously developed at KTH for melt spreading on dry substrates. The code capabilities are further extended to model the specific phenomena appearing in melt spreading over substrates under a water layer, such as multiphase flow and film boiling heat transfer. The S3E-2MWS-Ox-1 and PULiMS-E9 tests conducted at KTH for melt underwater spreading are used to validate the new code capabilities. The leading edge progression and final shape of the melt in both tests are reasonably predicted by the simulation, indicating the further developed MPS code is capable of simulating melt underwater spreading.