Solubility of uranium oxide in molten salt electrolysis bath of LiF–BaF 2 with LaF 3 additive

Abstract The solubility of UO2 in the molten mixtures of equimolar LiF–BaF2(1:1) with LaF3 as additive was studied in the range of 1423 K–1523 K. The molten fluoride salt mixture LiF–BaF2 LaF3 was equilibrated with a sintered uranium oxide pellet at 1423 K, 1473 K, 1523 K and the salt samples were collected after equilibration. Studies were conducted in the range of 10%–50% by weight additions of LaF3 in the equimolar LiF–BaF2(1:1) base fluoride salt bath. Solubility of UO2 increased with rise in LaF3 concentration in the molten fluoride in the temperature range of 1423 K–1523 K. At a given concentration of LaF3, the UO2 solubility increased monotonously with temperature. With mixed solvent, when UF4 was added as a replacement of part of LaF3 in LiF–BaF2(1:1)-10 wt% LaF3 and LiF–BaF2(1:1)-30 wt% LaF3, there was an enhancement of solubility of UO2.