Thermodynamic analysis of molten alkali halide mixtures by molecular dynamic simulations

We performed molecular dynamics (MD) simulations to estimate the thermodynamics of alkali halide mixtures as part of the safety analysis of advanced nuclear systems. We optimized specific parameters of Cs and F for a Busing–Ida–type interatomic potential model and calculated the enthalpy of mixing of alkali halide mixtures. The calculated enthalpy of mixing of common-ion binary systems reproduced the relationship among the enthalpies of mixing of these systems obtained from experimentally measured values. On the other hand, the MD simulations of the LiF-CsI reciprocal system showed the liquid–liquid phase separation, and the enthalpy of mixing obtained by the MD simulations was a better estimation than that obtained from the excess Gibbs energy equation, which is invalid for such mixtures. Although the enthalpies of mixing estimated by the MD deviated from literature values in some cases, the MD simulations with a Busing–Ida–type potential model can be used to estimate the thermodynamics when mixing the alkali halide mixtures. •Specific parameters for Busing-Ida type interatomic potential were determined.•MD reproduced the experimental values of enthalpy of mixing of alkali halides.•MD also reproduced the liquid-liquid phase separation in LiF-CsI reciprocal system.