Säkerhetsanalys av brandbekämpning i kritiska utrymmen på Forsmark 1

Sammanfattning: In order to maintain a high safety level at a nuclear power plant it is important not only to measure the reliability of the components and systems of the plant, but also to investigate how the plant responds to human actions. One of the most hazardous situations in managing a power plant is fire occurring in critical areas. This study concerns the prospect of the local fire brigade to suppress a fire that has started in one of the most critical rooms for maintaining high reactor safety. The model created gives an indication on the possibilities of succeeding in suppressing a fire. In order to get a more reliable fire fighting the following advice are given: - Let the fire brigade go rounds in the plant together with the personnel, during which recommended fire suppressing methods are determined to avoid long preparation time in an actual situation. - Prepare rooms with two subsystems to make them partly with no voltage. - Give the fire brigade better feedback from actual events on nuclear power plants. - Education and training in suppressing fires in electrical equipment. The probabilistic safety assessment strives to be as realistic as possible. Consequently this study recommends not giving credit for the manual fire fighting in some of the rooms. Rooms such as corridors, which are not as problematic when it comes to fire suppressing, can be treated differently in the safety analysis.