Advanced Head End for the Treatment of Used LWR Fuel

A novel dry head-end process is being developed. The main goals are the separation of cladding from fuel and the upfront removal of problematic fission products while facilitating the downstream processing. Cold tests using surrogate pellets and tests on a scale of tens of milligrams using actual used fuel are very promising. The initial tests showed that the process can be performed at significantly lower temperatures than those for standard voloxidation by using a mixture of NO{sub 2}/O{sub 2} or NO{sub 2}/O{sub 3} to produce a fine red powder of UO{sub 3} and to release all the tritium and iodine. This powder - containing the uranium as UO{sub 3}, transuranium actinides, and nonvolatile fission product oxides - is readily soluble in dilute acids. Alternatively, the tests showed that the UO{sub 3} powder can be contacted with NO{sub 2}(N{sub 2}O{sub 4}) gas or liquid at room temperature to produce metal nitrates.