Using the Quasi-chemical formalism beyond the phase Diagram: Density and viscosity models for molten salt fuel systems

CALPHAD models to compute the density and viscosity of four keystone systems related Molten Salt Reactor (MSR) technology have been optimized: NaCl-UCl3, LiF-ThF4, LiF-UF4, LiF-ThF4-UF4. Revised thermodynamic assessments all systems, using modified quasichemical formalism in quadruplet approximation for description liquid solutions, are reported. In case phase diagram mixing enthalpy data available literature taken into account. For fluoride recently published on some solid phases account, while retaining most descriptions solutions. The densities solutions modelled pressure-dependent terms excess Gibbs energy, viscosities then an Eyring equation. Both state functions through distributions.