Over the years, power plants have been hit by numerous severe weather events (storm, flood, heat wave...). EDF (Electricity of France) and ASN (Nuclear Safety Authority) want to assess the future impact of severe weather events on the power plants. Furthermore, recent research on storms estimates more accurate wind speed return values than before. For this reason, the severe wind value is an important parameter to quantify on a NPP (Nuclear Power Plant) site, in order to verify if the protection measures are sufficient or, if necessary, to design adequate protection.
To cope with those objectives, wind flow behavior around a PWR (Pressurized Water Reactor) nuclear power plant is studied. The goal of this work is to check that there is no exceeding local wind speed relative to the wind entering the site. The severe winds are characterized locally near the buildings in terms of location and amplitude. Different kind of topology for the nuclear power plant sites are studied in the project: near a cliff, in a plain or in a basin.
In our study, the CFD (Computational Fluid Dynamics) open source tool Code_Saturne developed at EDF-R&D is used to simulate the wind over a French PWR site located in nearly flat terrain in a plain. The 3D mesh includes buildings of the site. Several wind directions corresponding to the prevailing winds are studied. Two wind speeds corresponding to wind speed return values are studied (eg: the inlet wind speed is 25 m/s at 10 meter high for a return period of 50 years). Furthermore, several locations selected near buildings are studied carefully. Swirling flows have been viewed between buildings.
Analysis of the results shows that the wind speed near the buildings does not exceed the wind speed at the entrance of the domain for the three directions studied except near the cooling towers and above buildings. However, this result should not be generalized to other PWR sites due to the specificities of each site such as relief, buildings position, buildings size, roughness, wind rose... This methodology could be applied at other nuclear power plant sites.