Decommissioning nuclear research reactors in Germany

Some 45 research reactors, from zero-power assemblies to the high-flux reactor, exist in Germany at the present time; eighteen of them have been decommissioned, and three plants are in the stage of safe containment. In the light of the boundary conditions existing in research and for plant operation, another ten plants are likely to be decommissioned. Decommissioning and demolishing a research reactor is estimated today to involve financial expenditures of a least DM 30 to 40 million. Basically, decommissioning research reactors is not different from the same procedure applied to power reactors in terms of the regulatory and technical procedures to be executed. However, one major difference in practical execution arises from the activity inventory, which is several orders of magnitude smaller, a correspondingly lower local dose rate, and approximately a factor of 16 lower volumes of radioactive waste to be treated. For this reason, it should be borne in mind that, according to the INES scale, failures may occur in research reactors which may be classified not above INES level 1, according to plant design features. Decommissioning may take a number of variants, with safe containment for a specified period of time until final demolition, direct partial demolition of the plant, or immediate complete demolition. (orig.)