Modelling of the Fukushima Dai-ichi multiphase molten debris spreading using OpenFOAM software

Pshenichnikov, A.

Proceedings of the Pacific Basin Nuclear Conference (PBNC2026) (Internet), 8 Pages, 2026/04

Modelling of the corium propagation from RPV through the PCV to the suppression chamber is challenging. A geometry of approximately one fourth of the RPV and a part of PCV until the jet deflector was created and tested to reproduce the final debris shape as measured by TEPCO. A multiphase Volume-Of-Fluid (VOF) method proved that it can be used under clearly defined assumptions. It was figured out that using the viscosity values for completely liquefied corium and steel makes no sense in modelling of debris flow because the final PCV debris shape cannot be reproduced under these conditions.