Overview of the physical properties of molten salt reactor using FLiBe

Abstract

Currently, there are six Generation IV nuclear reactor designs in development. Four are fast neutron reactors, and all designs operate at higher temperatures that permit hydrogen production. Thus, the interest in fluoride salts has grown due to their hightemperature application in fission and fusion reactor designs. The aircraft propulsion project was the initial plan, which used molten salt as a coolant and was started by Bettis and Briant in the 1940s. The molten salt reactor has been designed to operate at temperatures of 700 to 800°C with fissile material dissolved in a molten fluoride salt composition. Molten fluoride salts are stable at high temperatures, show good thermodynamic properties, and can also dissolve actinides and fission products easily. It creates a candidate for a thorium reactor with more than 45% efficiency. The purpose of this work was to investigate the physical characteristics of two systems of fluoride salt combinations, namely LiF-BeF2 (FliBe) and LiF-NaF-KF (FliNaK), including melting temperature, density, and heat capacity. The aim is to characterize the advantages of the various designs proposed for Generation IV by reviewing properties evidenced by safety improvements and limitations.