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.

Thermal Property Modeling and Assessment of the Physical Properties of FLiNaK

“…Their reported maximum solid solubility of NaF in KF of 5 ± 0.5 mol % is somehow in agreement with Chanh measures (3–7 mol %), and it was also utilized in the optimization for the system together with the Δ mix H values of Hong and Kleppa (Figure g), with the values of Macleod again found to lie outside the range of others and not included. The reported small values for Δ C p ,, for the melt (Figure h), allowed the assumption of Δ C p = 0. The resulting optimization yielded an MQMQA interaction parameter of normalΔ G N a K / normalF .25em .25em ( J / normalm normalo normall ) = prefix− 137 + 0.97 T .25em ( K ) + ( 53 − 0.81 T ) X N a K / normalF with Δ G ex a two-sublattice model of the solid solution is normalΔ G normale normalx .25em ( J / normalm normalo normall ) = ( 26 , 750 ) · Y normalN normala · Y K + ( 20 , 000 ) · Y normalN normala 3 · Y K …”

“…Their reported maximum solid solubility of NaF in KF of 5 ± 0.5 mol % is somehow in agreement with Chanh measures (3–7 mol %), and it was also utilized in the optimization for the system together with the Δ mix H values of Hong and Kleppa (Figure g), with the values of Macleod again found to lie outside the range of others and not included. The reported small values for Δ C p ,, for the melt (Figure h), allowed the assumption of Δ C p = 0. The resulting optimization yielded an MQMQA interaction parameter of with Δ G ex a two-sublattice model of the solid solution is …”