Severe Accident Management at Ringhals PWR -Present Status and Future Work

In 1988 measures to mitigate the consequences of severe accidents were implemented at all nuclear power reactors in Sweden. They consisted of a filtered vent containment system and back-up sources to the containment spray system. The requirement of these measures was to reduce the releases to less than 0.1 pc of the core inventory of fission products (for a 1800 MWt reactor) leading to limited land contamination if a severe accident would occur. As part of the mitigating programme, new Emergency Operating Procedures (EOP) were developed. For the PWRs the Emergency Response Guidelines (ERG) were complemented with BERG (Beyond ERG), in which the main emphasis for the operator was to protect the containment. In separate projects, a knowledge based handbook for severe accident management has been developed, and long-term effects of a severe accident have been investigated. In this paper the present status of the severe accident management for Ringhals PWR is presented. Furthermore, and more important, it is discussed how it may be improved. The Importance to continue the work with severe accident management issues is also stressed. Such work gives the mental preparedness that an accident, although unlikely, may occur. This is a safety enhancement in itself