Density and thermal expansion of the FLiNaK melt

The density of a liquid mixture of lithium, sodium and potassium fluorides of eutectic composition (FLiNaK) was measured using gamma-ray attenuation technique over the temperature range from liquidus to 1010 K. Based on experimental data, an equation for the temperature dependence of density has been proposed. The obtained results on the volumetric properties of the FLiNaK melt have been compared with literature data. Using the approximation of an ideal solution, the temperature dependence of the FLiNaK density in the solid state has been calculated and the density jump during melting has been estimated.