ABSTRACT
Nuclear industry wastes have traditionally been treated by aqueous processing techniques to remove actinides or fission products. Aqueous processing systems have proven to be very effective at achieving high separation efficiencies but in general generate large amounts of low-level nuclear waste. This chapter discusses pyrochemical processing techniques for separating radionuclides from waste oxides and metals can be divided into the following three areas: metal decontamination, oxide residue treatment, and spent nuclear fuel treatment. Melt slagging or melt refining separates radionuclides from more noble metals, example, copper, nickel, or steel, by selectively oxidizing the radionuclides into a flux or slag. The oxides and halides of the actinides and fission products are thermodynamically more stable than most base metal oxides and halides. Carbonyl refining is based on the formation of gaseous metal carbonyls. Impurities in the nickel and radionuclides are left behind in the solid phase and the nickel carbonyl is transported through the gaseous phase, resulting in a separation.
