Recovery of Noble Metals from Insoluble Residue of Spent Fuel

Abstract

The recovery of Ru, Pd and Mo from the simulated insoluble residue produced in dissolver solution of spent fuel was studied by means of Pb extraction and the recovery was found to be more than 80% for Ru and Pd. It was also found that the recoveries of Ru, Pd and Mo were dependent on melting temperature and gas atmosphere. Observations by scanning electron microscopy and X-ray microanalysis indicated that the noble metals recovered in Pb button were contained in both forms of ε-Ru(Pd, Mo) alloy and single metal. The solubility in nitric acid of Pd recovered in Pb was much higher than that of Pd in ε-Ru(Pd, Mo) alloy, suggesting the separation of Pd from ε-Ru (Pd, Mo) alloy. The decontamination factor for Ce as a stand-in of Pu was determined to be around 200 for one stage.