An alternative conditioning method for cladding waste (Fp 13)

A typical waste form generated in the chop and leach process for reprocessing of irradiated nuclear fuel is the cladding material of the fuel. It mainly consists of leached hulls, but also contains other structural components like springs, plugs, spacers. Presently, this cladding waste is either temporarily stored in silos under water, or conditioned by embedment in cement. However, its final disposal necessitates an appropriate form of conditioning, due to the presence of fission products, activation products and long-living actinides. The actual research programme proposes an alternative conditioning method for cladding waste. The alternative method is based on the press compaction of the hulls up to at least 75 % of the theoretical density of zircaloy, the most representative cladding material for LWR fuels. The final conditioning then consists of encapsulation of the compaction products in a corrosion resistant shielding. In view of using clay as final disposal medium for highly active waste, this corrosion barrier might consist of a seamless lead containment. The main advantage of this method is the important volume reduction of this waste stream, which is of considerable economic significance for its final disposal. Furthermore it reduces the external contaminated surface to a large extent. It also decreases the pyroforicity hazard, associated with the handling of irradiated zircaloy material. Finally, the conditioned products are free of contamination, have the necessary mechanical strength for easy further manipulation and are resistant to corrosion during temporary land surface storage and in clay as a final disposal medium