Oil pool fire in an EPR-type containment

Simulation of oil fire in a containment of an EPR-type nuclear power plant has been carried out using the CFD (computational fluid dynamics) code FLUENT. The oil leak forms an oil pool below one of the main cooling pumps. The goal was to evaluate the temperature field near the steam generators during the different phases of fire. The concern is that water in the level measurement impulse pipelines, used to measure the water level in steam generators, may warm up and evaporate due to elevated temperature and cause spurious protection signals and false information. The initial state was estimated with a steady state simulation, which took into account the cooling system in the steam generator rooms and the pressure control systems of the containment. The systems were in operation until containment isolation took place. Two different predefined fire profiles were used with maximum heat output of 46 MW and 7.5 MW. The simulations were performed using 110 l and 880 l of lubrication oil. The rupture foils and hydrogen damper doors controlling the connection between the steam generator room and the dome area are described as well. These have influence in the flow field especially after the cooling system has stopped due to containment isolation signal. According to the simulations temperature near the steam generators on the fire side of the steam generator room may be so high that evaporation in the pipelines is possible in the case of 46 MW and 880 l of oil. With lower amount of oil and/or lower heat release rate of 7.5 MW the evaporation in the pipelines is unlikely. In all cases the steam generators on the other side of the steam generator room should maintain acceptable operating conditions.