COLLOIDAL PRODUCTS AND ACTINIDE SPECIES IN LEACHATE FROM SPENT NUCLEAR-FUEL

Two well-characterized types of spent nuclear fuel (ATM-103 and ATM-10 6) were subjected to testing under potential unsaturated conditions wi th simulated groundwater at 90 degrees C. The actinides present in the leachate were determined at the end of two successive periods of simi lar to 60 days. A vessel acid strip was done at the end of the second period. Both colloidal and soluble actinide species were detected in t he leachate which had pHs ranging from 4 to 7. The uranium phases iden tified in the colloids by transmission electron microscopy were schoep ite and soddyite. The actinide release behavior of the two fuels appea red to vary. Both the total amount of material released and the relati ve amount of each isotope released was different for the two fuels.