Validation & Sensitivity Study of a 1d Multiphysics Model for Graphite Moderated Molten Salt Reactor (MSRE) Using Gen-Foam

Abstract

The Molten Salt Reactor (MSR) is one of multiple advanced reactor designs that has received increased attention due to its enhanced safety features, reduced waste production, and increased non-proliferation capabilities. However, further research is necessary to fully prepare for large-scale implementation and overcome regulatory hurdles. The complex nature of the thermal hydraulics/neutronics design in MSRs requires extensive Multiphysics modeling, which sets it apart from conventional solid fuel reactors like Light Water Reactors (LWRs). This research aimed to explore the physical phenomena related to thermal MSRs. A preliminary step in the research involved studying the effect of turbulence model variations on molten salt behavior in circular heated pipes. Five turbulence models were evaluated for their impact on capturing thermal hydraulic metrics for molten salt flow. This step laid the foundation for further exploration of the complex physics involved in MSRs through Multiphysics modeling using the open-source GeN-Foam code. GeN-Foam, a novel OpenFoam-based solver, was specifically developed for the nuclear community and equipped with a point kinetics solver. With the help of a validated 1D model of the MSRE, a comprehensive uncertainty analysis was performed to better understand the impact of input and numerical uncertainties. Grid Convergence Index (GCI) was used to evaluate the relative importance of the input variables, while the One Factor at a Time (OFAT) and Latin Hypercube Sampling (LHS) methods were used to study input uncertainty. This research provides a significant contribution to the field of thermal MSRs and is an important step towards establishing trusted recommendations for a fuel salt scenario.