Thermal properties of NaF-KF and NaF-KF-MgF2 molten eutectic mixtures: experiment and simulation

Abstract

Molten fluoride salts are under development for use as fuel coolant and thermal storage in industrial nuclear energy production. This study focuses on the experimental and molecular dynamic investigation of thermal conductivity and ion diffusion in the eutectic molten salts of NaF-KF and NaF-KF-MgF2. Experimental and calculated data demonstrate that the temperature-dependent thermal conductivity can be accurately represented as a decaying linear function for both melts. The significant diffusion coefficient of fluorine ions in the NaF-KF molten system can be attributed to the considerable number of Coulomb repulsions among the abundant negative ions in the irregular system. The findings of this study provide insights into the behavior of NaF-KF and NaF-KF-MgF2 molten salt mixtures under operating conditions in high-temperature power plants.