Study of the effects related to the pressure on the division rupture between two areas in a nuclear plant in case of fire.

Inside a power plant, fire is the most frequent aggression that can occur. In confined buildings, a fire can cause the rise of the pressure that is able to damage the division between buildings by breaking fire doors. EDF wrote 3 reports dealing with the issue of pressure caused by a fire that present the creation of a screening method to discriminate the rooms without risk and the detailed analysis for the rooms that are not discriminated. After investigation from the IRSN and the ASN, EDF had to change some parameters of the study such as the leakage surface considered for fire doors that needed to be reduced. With these changes, almost all the criteria of the screening method needed to be reconsidered. The PFG without hydrocarbon source with a volume lower than 200m² couldn’t be discriminated anymore and the abacus for the PFL with liquid hydrocarbon had to be rebuilt. With the use of the zone cone MAGIC, used by EDF for the study of fire in confined area, coupled with the OpenTurns software, the abacus could have been remade. It also enabled to notice an oscillation effect in MAGIC during the underpressure phase that doesn’t appear in the experimental case CFS7 in similar conditions. This will need a further study from the R&D departure of EDF in a near future.