The Soft-Sphere Equation of State for Liquid Flibe

Molten Flibe (Li₂BeF₄) salt is a candidate material for the liquid blanket in the HYLIFE-II inertial confinement fusion reactor. The thermodynamic properties of the liquid are very important for the study of the thermohydraulic behavior of the concept design, particularly, the compressible analysis of the blanket isochoric heating problem. In this paper, a soft sphere model equation of state, which was used for describing liquid metals previously, is deployed with slight modifications for fitting the available experimental data for liquid Flibe. It is found that within the available temperature range the model gives a good agreement with experimental data for density, enthalpy and speed of sound. Additionally the model provides reasonable isotherms, spinodal line and predicts a “critical point”. The results show that the model has good thermodynamic behavior, although for a material like Flibe the “critical point” phenomenon is more complex than for pure component material.