Pyroprocessing in Japan

The integrated actinides recycle system for LWR oxide fuel and for FR metal fuel using pyrochemical technology is shown. This system also envisages the P&T of TRU elements contained within the high level liquid waste (HLLW) stream arising from aqueous reprocessing. The pyrochemical reprocessing consists of electrorefining with a solid cathode for uranium recovery and a liquid cadmium cathode for actinides collection in a LiCl-KCl salt bath, reductive extraction for recovering TRU elements in LiCl-KCl/Cd or LiCl-KCl/Bi using lithium as the reductant, and fuel fabrication by casting after removing salt and cadmium by distillation of the actinide products. The electrochemical reduction is applied to convert spent oxide fuels to metals in LiCl-KCl salt with the addition of Li₂O. To recover TRU elements, HLLW is converted to chloride for reductive-extraction. To facilitate chlorination, HLLW has to first be denitrated to obtain the oxides. The chlorination of oxides occurs in a LiCl-KCl bath. The MAs used in the preparation of FR U-Pu-Zr metal fuels resulted from electrorefining and reductive extraction and contain a small quantity of lanthanides that were separated along with the actinides. The is because there is only a small difference between the free energy of formation for the chlorides of lanthanides and actinides.