Analysis of the effect of fires and their consequences for the safe shutdown of a unit with a WWER-1000 reactor

This paper describes the status of work, and the results obtained, on the problem of safe shutdown of a nuclear power plant with a WWER-100 reactor (V-320) in the event of a fire. The study focused on Unit 4 of the Balakovo nuclear power plant, which has been in operation since December 1993; it started in 1996 and should be complete by December 1997. The methodology used for the analysis includes a deterministic approach to the analysis of safe shutdown, incorporating probabilistic safety assessment techniques. The study is based on the results of a probabilistic safety assessment, an analysis of the spatial distribution of equipment posing a fire risk and of fire-fighting measures at the plant, thermophysical modelling of the development of a large-scale fire, and operational statistics on fire risk factors and fires at plants with WWER-1000 reactors