Role, status and development of performance assessment in the Swedish nuclear waste management programme

So far, the R and D efforts made by the Swedish Nuclear Fuel and Waste Management Company concerning the final disposal of spent fuel have been dedicated to showing the feasibility of a safe disposal concept. In the future, a greater emphasis will be placed on site screening and ranking and on the successive optimization of the disposal system. Hence, a further development of the performance assessment methodology used in the KBS-1 and KBS-3 feasibility studies is necessary. This includes detailed research related modelling of basic processes and phenomena, radionuclide transport modelling, probabilistic systems analysis, database development and confidence enhancement by, for example, validation and verification of models. (author)