(374b) Solid State Separations of Cs and Sr from Licl-Based Salt for Electrochemical Processing of Spent Oxide Nuclear Fuel

Electrochemical processing technology is currently being used at Idaho National Laboratory for the treatment of metallic spent nuclear fuel used in the Experimental Breeder Reactor -II (EBR-II). In this process, spent nuclear fuel is electrochemically separated from fission products and other waste material from recyclable actinides. In order to convert oxide-based fuel into metallic form via electrochemical processing it is necessary to have an oxide reduction step. In the oxide reduction process, certain fission products, including Cs and Sr, partition into the salt phase and form chlorides. Their concentrations in the salt continue to increase as more spent fuel is reduced. The fission product loaded salt can either be disposed of directly into a ceramic waste form or regenerated by selectively removing fission products. Removal of fission products will essentially reduce the volume of the ceramic waste produced. Solid-state ion exchange tests conducted with zeolite-A and LiCl-based salt at 500?aC has shown a very high selectivity for Cs and Sr to partition into the zeolite phase. However, a significant uptake of chloride into the zeolite was also noticed. Preliminary solid -state tests conducted to minimize chloride uptake while still achieving ion exchange will be discussed in this paper.