Impact of advanced fuel cycles on radioactive waste disposal in a clay formation. Results obtained by SCK•CEN in the framework of the EC Red-Impact project

The Red-Impact project was a research project in the 6th Framework Programme of the EC, of which the main objective was to assess the impact of partitioning and transmutation (P&T) on radioactive waste management and geological disposal. The present report discusses the main results obtained by SCK•CEN in the framework of this project. Red-Impact started with the identification of five representative fuel cycle scenarios, for which the volumes and composition of the resulting radioactive wastestreams were estimated. Subsequently, the implications for geological disposal of the main waste streams, in particular the spent fuels, high-level waste and long-lived intermediate-level waste, were evaluated. The SCK•CEN study focussed on two indicators: the required repository size per unit produced electricity and the long-term radiological dose caused by the considered waste types for disposal in a Boom Clay environment. Since high-level waste arising from advanced fuel cycles generates less heat than spent fuel from a "once through" fuel cycle, it appeared that a reduction up to factor 3 of the required size of the geological repository is possible. The impact of P&T on the long-term radiological consequences is about negligible, because the resulting doses are essentially due to mobile long-lived fission and activation products.