Transient coupled calculations of the Molten Salt Fast Reactor using the Transient Fission Matrix approach

International audienceIn this paper we present transient studies of the Molten Salt Fast Reactor (MSFR). This generation IV reactoris characterized by a liquid fuel circulating in the core cavity, requiring specific simulation tools. Aninnovative neutronic approach called ‘‘Transient Fission Matrix” is used to perform spatial kinetic calculationswith a reduced computational cost through a pre-calculation of the Monte Carlo spatial and temporalresponse of the system. Coupled to this neutronic approach, the Computational Fluid Dynamicscode OpenFOAM is used to model the complex flow pattern in the core. An accurate interpolation modeldeveloped to take into account the thermal hydraulics feedback on the neutronics including reactivityand neutron flux variation is presented. Finally different transient studies of the reactor in normal andaccidental operating conditions are detailed such as reactivity insertion and load following capacities.The results of these studies illustrate the excellent behavior of the MSFR during such transients