Thermal properties of binary chlorides relevant to molten salt chemistry

Among proposed Generation IV nuclear reactors, the molten salt fast reactor (MSFR) has some of the most promising inherent safety features available. Among these includes the solidification of the molten salt matrix upon loss of external heating, preventing runaway. Other convenient features include online reprocessing and increased fuel variety. A major hurdle for MSFR design is the lack of fundamental data on the component salts, and the resulting fission and corrosion product speciation. While MSFRs are typically designed for use with fluoride salts, chloride salts have shown promise, and have had increased interest in recent years. A better understanding of the fundamental thermodynamic properties of chlorides would aid in the design of more efficient and more precise separations of the spent fuel salt mixture for recycling of fissile isotopes. This review has collected and analyzed existing literature data on the relevant thermochemical and thermophysical properties including: boiling / melting / sublimation points, heat capacity, vapor pressure expressions, enthalpic / entropic / free energy formation and phase change values. The elements of interest include that of fuel salts (actinides), solvent salts (alkali and alkaline earth metals), and fission and corrosion product (main group, transition metal, and rare earth element) chloride salts.