Conference paper. Lead Solidification and Re-Melting in a Pool: Experiment and CFD Modelling

This paper describes and analyses a lead pool solidification re-melting experiment performed in the SESAME-stand facility and its CFD modelling. Lead-cooled Fast Reactors (LFRs) are promoted by the Generation IV International Forum (GIF) because of molten lead ́s good thermo-physical properties, nuclear sustainability and safety. As lead melting point is 327.5°C, partial freezing can occur during specific operational regimes and impede the flow pattern. In this case, the core decay heat removal might be limited and thus, the reactor safety can be affected. To investigate this issue, in the SESAME H2020 project, the dedicated SESAME-stand experimental facility with a vessel type geometry has been designed, built and operated at Research Centre Rez (CVR),releasing a complete data base of its operation. In parallel, CFD models have been built, compared to the data and progressively improved to a somewhat satisfactory level. Some discrepancies still remain and some experimental results still need explanation. Improving understanding of the data and trying to reduce the discrepancies is the starting point of this work. In particular, the modelling was found extremely sensitive to physical parameters and constraints such as the external thermal conditions as well as the vessel ́s surface emissivity. Focusing on a solidification and re-melting transient, the data were analyzed and compared with a 90o sector CFD model of the pool. The 90 o restriction forbids to capture observed flow asymmetries. Thus, it was proceeded with a full domain simulation and shown what additional features of the flow were captured.

@Proceedings{MPMA22,
  editor       = {Moreau, V. and Profir, M. and Melichar, T. and Achuthan, N.},
  title        = {Conference paper. Lead Solidification and Re-Melting in a Pool: Experiment and CFD Modelling},
  series       = {19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) Brussels, Belgium, March 6 - 11, 2022, ISBN 9789076971261},
  year         = {2022},
  keywords     = {CFD, HLM, LFR, pool thermal hydraulics, lead solidification},
  url          = {https://publications.crs4.it/pubdocs/2022/MPMA22},
}