Experimental Study on Alkali and Alkaline Earth Metal Oxide Solubility in LiCl at 923 K

摘要

During the electrolytic reduction of oxide usednuclear fuel in molten LiCl, SrO and Cs_2O are dissolvedinto the molten salt electrolyte. Because 90Sr and 137Cs arehighly heat-generating fission products, the heat load ofthe reduced metallic spent fuel largely decreases.Therefore, the separation of Sr and Cs from the actinidematerial stream will reduce a geological disposal facilityfootprint. It is known that SrO and Cs_2O react with LiCland form SrCl2 and CsCl in LiCl melts, however, thesolubility of these oxides in molten LiCl have not beenproperly studied.The present study investigates the solubility of theLi_2O in LiCl at 923 K, preceding SrO and Cs_2O studies.Samples were taken at equilibrium from the molten LiClsolution in contact with 5, 10, 15 wt.% of Li_2O. Thematerial composition of the samples was analyzed by acidtitration for Li_2O. The measured solubility was alsocompared to the solubility calculated from the opencircuit potential between indicator and referenceelectrode at saturation of Li_2O.