Development of the Molten Salt Thermal Properties Database − Thermochemical (MSTDB−TC), example applications, and LiCl−RbCl and UF3−UF4 system assessments

The Molten Salt Thermal Properties Database − Thermochemical ( MSTDB−TC ) has been developed to support thermodynamic modeling of fluoride- and chloride-based systems for molten salt reactors (MSRs). Utilizing data from available literature and original work, the current MSTDB−TC Ver. 1.2 contains models for 96 pseudo-binary systems, 37 pseudo-ternary systems, 42 solid solutions, 229 stoichiometric compounds, and 130 gaseous species. This includes 67 reassessed systems and 13 original system models. The reassessment of the LiCl−RbCl pseudo-binary system and the original assessment of the UF ₃−UF ₄ pseudo-binary system are included as examples of those efforts and provide improved representations of those systems. The database continues to be expanded, adding systems of relevance to the wide variety of MSR concepts. To illustrate applications for MSTDB−TC, phase equilibria were computed to understand the effect of varying uranium content in the KCl−MgCl ₂−NaCl−UCl ₃ system. In an example of how such calculations can support corrosion modeling, the control of redox potential by the UF ₃:UF ₄ ratio in the LiF−BeF ₂−UF ₃−UF ₄ system is demonstrated and used to assess corrosion potential for typical alloy constituents.