A numerical benchmark for modelling phase change in molten salt reactors

Mateusz Pater, Bouke Kaaks*, Bent Lauritzen, Danny Lathouwers

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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The design of a molten salt reactor is largely based on CFD simulations. Phase change plays an important role in the safety of the reactor, but numerical modelling of phase change is particularly challenging. Therefore, the knowledge of the margin of error of CFD simulations involving phase change is very important. Relevant experimental validation data is lacking. For this reason, a numerical benchmark designed after the freeze valve is proposed. The benchmark consists of five stages, where with each step more complexity is added. The stepwise addition of complexity allows for pinpointing potential sources of discrepancy. Results were obtained with three different codes: STAR-CCM+, OpenFOAM, and DGFlows. The results were found to be largely consistent between the codes, however the addition of conjugate heat transfer introduced some discrepancies. These results indicate that careful consideration is needed when coupling conjugate heat transfer solvers with solid–liquid phase change models.
Original languageEnglish
Article number110093
JournalAnnals of Nuclear Energy
Number of pages15
Publication statusPublished - 2023


  • Benchmark
  • Freeze valve
  • Melting
  • Molten salt reactor
  • Phase change


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