Effects of electro-chemical reduction process on the environmental impact of geologic disposal

Effects of electro-chemical reduction process of light-water reactor (LWR) spent fuel are investigated with respect to the peak toxicity release rate of a high-level waste repository. The waste from the electro-chemical reduction process is compared to the vitrified waste in H12 reference repository, assuming the same repository capacity. If the inventory of 237Np is reduced between 0.1 mol/canister and 0.4 mol/canister by the reduction process, the radiotoxicity release rate from the repository is reduced significantly. Reduction of 237Np below 0.1 mol/canister would not reduce the overall toxicity release rate further because 135Cs becomes the predominant contributor. Since the inventory of 135Cs in the waste is not affected by the reduction process, the contribution of 135Cs to the toxicity release is not affected. (author)