Dynamic analysis for a 2 MW liquid-fueled molten salt reactor

In a liquid-fueled molten salt reactor (MSR), the fuel salt acts as both fuel and coolant, and the fission energy is released into the fuel salt immediately. The delayed neutron precursors drift through the graphite channels in the core and the primary loop during operation. Therefore, the dynamics for a MSR is characterized by the strong interplay between the neutronics and thermal hydraulics, which is significantly different from that of a solid-fueled reactor, such as PWR. In this study, a dynamic analysis for a graphite moderated, fluoride based, liquid-fueled molten salt reactor with a power of 2 MWth (TMSR-LF) is carried out based on a coupled neutronics/thermal hydraulics code named TMSR-2D. The steady-state characteristics including the distributions of flow field, temperature and neutron fluxes, and effective delayed neutron fraction under different fuel flow rates, transients perturbed by fuel pump start-up and coast-down, overcooling and overheating of inlet fuel and reactivity insertion are simulated and analyzed. The numerical results indicate that the dynamic behavior of TMSR-LF is acceptable in the aspect of reactor safety. Furthermore, the dynamic analysis offers valuable information for future construction and operation of this experimental reactor.