Separation of actinides from LWR spent fuel using molten-salt-based electrochemical processes

Results are presented of work done at Argonne National Laboratory to develo p a molten-salt-based electrochemical technology for extracting uranium and transuranic elements from spent light water reactor fuel. In this process, the actinide oxides in the spent fuel are reduced using lithium at 650 deg reesC in the presence of molten LiCl, yielding the corresponding actinides and Li2O. The actinides are then extracted from the reduction product by me ans of electrorefining. Associated with the reduction step is an ancillary salt-recovery step designed to electrochemically reduce the Li2O concentrat ion of the salt and recover the lithium metal. Experiments were performed at the laboratory scale (50 to 150 g of fuel and 0.5 to 3.5 l of salt) and engineering scale (3.7 to 5.2 kg of fuel and 50 l of salt). Laboratory-scale experiments were designed to obtain informatio n on the fundamental factors affecting process rates. Engineering-scale exp eriments were conducted to verify that the parameters controlling process s caleup are sufficiently understood, and to test equipment and operating con cepts at or near full scale. All indications are that the electrochemical-b ased process should be workable at practical plant sizes.