These streams include (1) the relatively pure uranium metal fraction; 1 (2) miscellaneous metal wastes containing the noble metal fission products, cladding, and reactor assembly hardware; and (3) zeolites containing the transuranics and the alkali metal, alkaline earth, and rare-earth and other fission products. In the ANL process, the zeolites would be converted to a glass-bonded zeolite waste form, and the miscellaneous metals would be formed into ingots of a corrosion-resistant metal waste form (a zirconium-iron alloy). ANL believes that both waste forms would be suitable for disposal in a geologic repository. However, ANL is also investigating an alternative flow sheet (Fig. 3) in which the transuranic elements in the spent fuels would be combined with the undissolved material remaining in the anode baskets and incorporated in the Fe/Zr metallic waste form.

Figure 3. Alternative ANL electrometallurgical process scheme to generate a single metallic waste form. In adaptation for treatment of plutonium, the plutonium would be introduced at the point denoted spent fuel, metallic and oxide forms.

With respect to the disposition of surplus WPu, the primary features of the electrometallurgical spent fuel treatment process that are applicable to immobilization are:

  1. the Li reduction step for the treatment of TRU-rich oxide residue;

1  

The uranium metal produced in the electrorefining step has up to the present time been designated as a product to be stored, but not as a waste. Its final disposition remains to be decided.



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