Reliability-based design of structural members for nuclear power plants

The reliability of load bearing structural members in NPP has been proved by 1st order reliability theory. Studies on the temperature development in safety related compartments and the failure probability of adjacent concrete members were performed. Special effects (e.g. due to forced ventilation and fire extinguishing systems) are accounted for in the calculations with a post-flashover heat balance model. Simplified failure models describing the load bearing capacity of concrete members were applied to check the reliability of different types of building members. The results indicate that the member temperatures and the life loads are the most important parameters. Therefore the practical design may be performed by using partial factors for the temperatures and reduction factors for the life loads. It turned out that as a rule 90 minutes fire duration acc. to DIN 4102 is a sufficient value for NPP fire compartments