Study of an aqueous process using hydrochloric acid for radioactive waste containing uranium

Solid and liquid radioactive waste derived from research activities, such as development of uranium refining and conversion, has been stored at the Japan Atomic Energy Agency Ningyo-toge Environmental Engineering Center. The solid uranium waste, excluding metal waste currently totals 1500 tons. In this study we estimated the applicability of aqueous processes using hydrochloric acid for CaF2 and NaF wastes treatment. Dissolution experiments were carried out by adding these wastes into 1N HCl with AlCl3 6H2O. The dissolution rates of CaF2 and NaF wastes were 99.78% and 100%. Dissolved uranium was recovered from the HCl solution as UO4 using H2O2. The recovery rates of uranium from CaF2 solution and NaF solution were 98.2% and 99.7% respectively. It was confirmed that temporary estimated high level waste generation could be reduced considerably by an aqueous process using hydrochloric acid. (authors)