Health physics of the decommissioning of NS 'Otto Hahn' from the decommissioning company's viewpoint

Some of the points to be discussed in the report are listed below: The essential differences between backfitting measures in current Nuclear Power Plants and in the decommissioning of nuclear facilities will be described. The essential factors for the successful decommissioning of nuclear facilities as structural knowledge of the facilities as well as exact knowledge of the radiological state of the facilities for the selection of work method and work measures as well as for radiation protection measures to be taken. Explanation of the precautionary measures to minimize the aerosol release and the radiation exposure. The aerosol release dependent on the degree of contamination and on the separating procedure selected will be shown on one example for the dismantling of a heat exchanger. Description of the method of procedure to minimize the indivdual dose during decontamination of the fuel element storage pit. For decontamination - whether soft or hard decontamination - in Nuclear Power Plants, the decontamination of the secondary plant of the OTTO HAHN will be described exemplarily. Experience gained when the OTTO HAHN was decommissioned has revealed that the accumulated dose exposure per man and year can be restricted to approx. 15 m Sv (1.500 mrem). Similar values are also to be expected for the decommissioning of Nuclear Power Plants - even if this should take place 5 - 10 years after shutdown. (orig./RW)