First reactor in the Federal Republic of Germany built on the basis of a national concept and independently in the Research Centre Karlsruhe. The FR 2 was a D2O-moderated and cooled research reactor using UO2 enriched to 2% as a fuel and with a power of 44 MW. The reactor entered operation on 7th March 1961. Following 20 years of operation without considerable malfunctions the FR 2 was finally shutdown on 21st Dec. 1981. The aim of the decommissioning measure – the safe inclusion of the reactor unit – and the disassembly of all residual systems was reached in November 1996.