DEMOLITION OF NUCLEAR INSTALLATIONS - CRI TERIA FOR THE HANDLING SYSTEMS

Fourteen pressurized water (PWR) and six boiling water (BWR) reactors are currently in operation in Germany. Some of these power plants will reach the end of their service life after the year 2000, and most of them will have to be decommissioned after 2010. This means that demand for technical decommissioning and disposal techniques will grow rapid ly after 2000 at the latest. The external building structure of a nucl ear power plant is not exposed to radioactivity in operation. The radi ation generated by nuclear fission extends as far as the metal walls a nd structural parts, where it causes radioactive isotopes to be genera ted. The radioactivity is firmly bound in these activated metal compon ents. Once the fuel elements and the radioactive waste have been remov ed from the plant at the beginning of the decommissioning phase, some residual activation remains in the components close to the core (react or pressure vessel, RPV internals, biological shield). The critical st eps in decommissioning are the disassembly of the highly activated rea ctor pressure vessel and its internals. For reasons of radiation prote ction, these steps must be conducted by remote operation and, it possi ble, shielded by water. The handling equipment used for this purpose m ust meet very stringent requirements in terms of resistance to ambient conditions and must be extremely rigid. For future decommissioning an d demolition activities, an effective dismantling strategy and the han dling equipment to go with it must be developed.