Simulation of transient processes in molten salt reactors

Justification of a reactor fuelled with circulating molten metal fluoride salts requires the development of special tools for multiphysics simulation. The NRC “Kurchatov Institute” (Moscow, Russian Federation) has developed the MULTIMSR software package for simulating neutron-physical and thermal-hydraulic processes of molten salt nuclear reactors in a 3D setting. The software additionally includes the MSR-NODES tool, which simulates the system in a simplified one-dimensional formulation using the point kinetics approximation to calculate the reactor neutron power. The developed software package was used to simulate transient processes with the loss of forced cooling in the intermediate circuit of a molten salt reactor. The simulation results indicate a similar oscillatory nature of the transient change in the average temperature of the core fuel salt in 1D and 3D simulations. The possibility of using simplified models to study transient processes in molten salt reactors is considered.