Solubility of Pu and rare-earths in LiCl-Li2O melt

Abstract The solubility of Pu and rare-earths (REs) were measured in LiClLi 2 O melt where individually the oxides precipitated. The solubility of Pu(III) was measured at 923 K as a function of Li 2 O concentration. After every addition of Li 2 O to increase the Li 2 O concentration in the melt, the Pu concentration increased and showed a saturation in several hours. The stepwise variation means that the Pu concentrations at the saturation are regarded as the Pu solubility at the respective Li 2 O concentrations. The solubility of Nd(III), Gd(III), Pu(IV), and Ce(IV) were also measured as a fanction of Li 2 O concentration, and all of them increased with increased Li 2 O concentration. Especially, the solubility of the trivalent Pu and REs were related almost proportionally with the Li 2 O concentration. The solubility of La(III) and Pr(III) were measured in molten LiCl saturated with Li 2 O between 883 and 973 K. The logarithmic solubility was related linearly with the reciprocal temperature. The systematic measurement indicated that the solubility was higher for the element with a larger ionic radius as to the trivalent Pu and REs.