Experimental investigation of the physical properties of salt melts containing sodium and lithium fluorides and beryllium difluoride

Experimental measurements of the basic physical properties of the melt NaF-LiF-BeF2 are presented as validation of the concept of a molten-salt reactor for burning actinides from spent fuel from light-water reactors. Compositions which are characterized by the minimal molar fraction LiF 15-17% and BeF2 25-27% and meet the special requirements for a fuel salt for the concept under study are found. The melts of the fluorides of three metals have an acceptable melting temperature (< 500 degrees C), permit dissolution of actinide and lanthanide trifluorides to molar fraction 2% and higher at 600 degrees C, possess good neutron-physical (even without enrichment with respect to Li-7) and thermophysical properties, are compatible with nickel-molybdenum alloys to temperature 750 degrees C, are inexpensive and are not strongly activated by neutrons so that they do not present a long-term disposal risk.