Investigation on influence of crust formation on VULCANO VE-U7 corium spreading with MPS method

Yusan Yasumura*, Akifumi Yamaji, Masahiro Furuya, Yuji Ohishi, Guangtao Duan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


In a severe accident of a light water reactor, the corium spreading behavior on a containment floor is important as it may threaten the containment vessel integrity. The Moving Particle Semi-implicit (MPS) method is one of the Lagrangian particle methods for simulation of incompressible flow. In this study, the MPS method is further developed to simulate corium spreading involving not only flow, but also heat transfer, phase change and thermo-physical property change of corium. A new crust formation model was developed, in which, immobilization of crust was modeled by stopping the particle movement when its solid fraction is above the threshold and is in contact with the substrate or any other immobilized particles. The VULCANO VE-U7 corium spreading experiment was analyzed by the developed MPS spreading analysis code to investigate influences of different particle sizes, the corium viscosity changes, and the “immobilization solid fraction” of the crust formation model on the spreading and its termination. Viscosity change of the corium was influential to the overall progression of the spreading leading edge, whereas termination of the spreading was primarily determined by the immobilization of the leading edge (i.e., crust formation). The progression of the leading edge and termination of the spreading were well predicted, but the simulation overestimated the substrate temperature. Further investigations may be necessary for the future study to see if thermal resistance at the corium-substrate boundary has significant influence on the overall spreading behavior and its termination.

Original languageEnglish
Pages (from-to)119-127
Number of pages9
JournalAnnals of Nuclear Energy
Publication statusPublished - 2017 Sep 1


  • Crust immobilization
  • MPS method
  • Severe accident
  • Spreading
  • Viscosity

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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