[en] The task of the TUeV-Norddeutschland was limited to radiation protection. Apart from the evaluation of the radiological radiation protection, simultaneous control with evaluation of the measuring procedures was effected. The complete shut-down of the plant has been entirely documented. (DG)

[en] Gammaspectrometrical investigations during shutdown showed mostly Co-60 in the contaminated regions. The scintillation dosemeter developed at the PTB has been used for measuring the environmental radiation. Material samples taken at random have been inspected gammaspectrometrically in order to prove the reliability of the contamination measurements accompanying the shutdown work. (DG)

[en] The shut-down activities were divided in 4 stages. After the preliminary work the loops, systems and components were disassembled and packed up. Then followed the evacuation of the RPV with shieldtank and the decontamination of the components remaining on the ship and of the ship structures. The moved masses and activities as well as their places of origin have been documented. (DG)

[en] With the Otto Hahn the comparison of guidelines has been performed for the first time. The office for working protection attended to the licensing procedures as well as to the control during normal operation. The progress of shut-down and the man-rem result showed that the licensing to the extent defined by the rule was sufficient and practicable. The principle of control in several stages carried out by the orderer, the TUeV, the office for industrial safety and the PTB has proved true. (DG)

[en] For the bulk cargo ship had been chosen the advanced PWR, the secial characteristic of which is an integrated primary loop with automatic pressurisation. Altogether the Otto Hahn covered over half a million sea-miles. In-service inspections and examinations of the reactor plant were effected by control authorities every year. During the whole operating period the NS Otto Hahn showed a safe and reliable behaviour even from the view of radiation protection. (DG)

[en] The concept of the total elimination of the nuclear part of the drive system had been decided upon in consideration of the NIS-study as well as of the plannings for post-investigations on components. This meant the removal of all radioactive components. The entire reactor plant with the exception of the safety containment and the concrete constructions of the secondary protection system and of the service pool had to be disassembled. Apart from the protection of the environment the concept took particularly the protection of the staff into account. The material treatment envisaged components with difficult decontamination properties to be put into casks or special containers according to their size. (DG)

[en] After successful conclusion of the decommissioning of NS Otto Hahn during the summer of 1982 a specialists meeting was organized by GKSS-Forschungszentrum Geesthacht GmbH in order to give information about planning, procedures used and experience resulting from the decommissioning process. The state-of-the-art decommissioning techniques as used for this first German nuclear powered merchant ship are shown by experts from licensing authorities, the decommissioning company and the ship operator. (orig./HP)

[en] The concept of handling the disassembly of active system components planned the application of mechanical separation methods. Thermal separation methods came into question only in exceptional cases. In general, the required shielding was realized by appropriate filling of the container or by additional shielding with plates of rolled or cast lead obtained during disassembly. The heat exchangers shielded by cast steel casings with flanged closures could only be put into the containers after being disassembled. The shielding required for the transport and storage of the RPV with shield tank was performed by using material available on board. The decontamination measures and the release procedure were rendered difficult due to the layout of a great part of the large shieldings in the region of the service room and waste water tank shieldings. (DG)