Current activities in criticality analyses for final disposal of spent nuclear fuel and fissile material containing waste in Germany

This paper gives a short overview on the work which was done recently or is underway for criticality safety analyses for final disposal of fissile material containing waste and spent nuclear fuel in Germany. For Plutonium containing low-level waste a modification of criticality safety limits is proposed, taking into account the fractions of Pufiss and 240Pu. For final disposal of spent nuclear fuel studies on long term sub-criticality are being performed with the aim of comparing different host rock materials. The paper reports on first results of generic criticality analyses for a clay formation. The analyses are based on long term scenarios, which were proposed by experts in geo-chemistry, dealing with long term problems in disposal research. (author)