Thermal Properties of Binary Chlorides Relevant to Molten Salt Nuclear Chemistry

Among proposed Generation IV nuclear reactors, the molten salt fast reactor (MSFR) has some of the most promising inherent safety features available. This includes isolation and solidification of the salt matrix in emergency situations 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 species. While current MSFRs design research and development is focused on fluoride salts, chloride salts have shown promise and have received increased interest in recent years. A better understanding of the fundamental thermodynamic properties of chlorides would aid in the design of more efficient and 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, molar heat capacity, vapor pressure expressions, enthalpic/entropic/free energy formation and phase change values. The elements of interest include those of the fuel salts (actinides), the solvent/coolant salts (alkali and alkaline earth metals), and contamination salts, namely fission and corrosion products (main group, transition metal, and rare earth element). Graphical Abstract