In a hypothetical severe accident in a light water reactor (LWR) nuclear power plant, there is a possibility that molten core released from the reactor vessel gets in contact with water in the containment vessel. In this so-called fuel-coolant interactions (FCIs) process, the melt jet will breakup into fragments, which is one of the important factors for a steam explosion, as a potential threat to the integrity of the containment vessel. In order to investigate the melt-jet breakup with solidification processes, a multiphase particle method is developed in this study. Benefiting from its Lagrangian description and meshless framework, the large deformed interfaces could be directly and easily captured by the particle motions. In this study, surface tension is modelled using the contour continuum surface tension model, while the solidification processes are represented by the viscosity escalation. Two important multiphase instabilities, namely the Rayleigh-Taylor instability and the Kelvin-Helmholtz instability, are firstly studied since they play important roles during the melt-jet breakup. After that, a bubble rising benchmark is carried out to show the feasibility of modelling for deformation and collapse. The results achieved so far indicates that the developed particle method is capable to analyse the melt-jet breakup with solidification processes.


Development of a Multiphase Particle Method for Melt-Jet Breakup Behavior of Molten Core in Severe Accident

Division / Sponsors: 
Power Division & Nuclear Engineering Division (NED)

Power Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/POWER/POWER2020/volume/83747

International Conference on Nuclear Engineering
Paper Proceedings: https://asmedigitalcollection.asme.org/ICONE/ICONE2020/volume/83761

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