Thermodynamic description of the K, Be//F, Cl salt system with first-principles calculations

Thermodynamic Assessment of CrCl2 with NaCl–KCl–MgCl2–UCl3–UCl4 for Molten Chloride Reactor Corrosion Modeling

“…The need for this concession in the modeled phase equilibria is due to the tendency of UCl 4 to form monomer complexes of varying coordination when mixed with heavy secondary cations . Pure species that exhibit complex speciation in mixtures of alkali chlorides have been successfully modeled using the MQMQA via the inclusion of multiple endmembers . The approach improves the calculated phase equilibria at all compositions by using multiple quadruplets for selected endmembers that each contribute to the overall SRO, thus allowing a more complex melt coordination environment as a function of temperature and composition.…”

“…The first nearest-neighbor (FNN) to SNN correlation factor, ζ A/Cl , is given by eq as defined by Wang et al based on the endmember cation (Z A/X A ) and anion (Z A/X X ) coordination numbers. The values for the alkali chlorides with MgCl 2 and UCl 3 were determined previously, with eqs and containing the values for the divalent chlorides and UCl 4 , respectively, as determined from Z A/X A = 6 and Z A/X X = Z A/X A / n , where n is the cation valence. ζ normalA / normalX = 2 normalZ normalA / normalX normalA normalZ normalA / normalX normalX normalZ normalA / normalX normalA + 0.25em normalZ normalA / normalX normalX 0.25em ζ Mg / Cl = ζ Cr / Cl = 4 0.25em ζ normalU IV / Cl = 2.4 …”

“…The first nearest-neighbor (FNN) to SNN correlation factor, ζ A/Cl , is given by eq as defined by Wang et al based on the endmember cation (Z A/X A ) and anion (Z A/X X ) coordination numbers. The values for the alkali chlorides with MgCl 2 and UCl 3 were determined previously, with eqs and containing the values for the divalent chlorides and UCl 4 , respectively, as determined from Z A/X A = 6 and Z A/X X = Z A/X A / n , where n is the cation valence. …”