Verification of moltres for multiphysics simulations of fast-spectrum molten salt reactors

Modeling strongly coupled neutronics and thermal–hydraulics in liquid-fueled MSRs requires robust and flexible multiphysics software for accurate simulations at reasonable computational costs. In this paper, we present Moltres and its neutronics and thermal–hydraulics modeling capabilities relevant to multiphysics reactor analysis. As a MOOSE-based application, Moltres provides various multiphysics coupling schemes and time-stepping methods, including fully coupled solves with implicit time-stepping. We verified Moltres’ MSR modeling capabilities against a multiphysics numerical benchmark developed for software dedicated to modeling fast-spectrum MSRs. The results show that Moltres performed comparably to participating software packages in the benchmark; the majority of the relevant quantities fell within one standard deviation of the benchmark average. Among the participating multiphysics tools in the benchmark, Moltres agrees closest to the multiphysics tool from the Delft University of Technology due to similarities in the numerical solution techniques and meshing schemes.