The N3S system applied to environmental problem: the simulation of Paluel thermal plume

The discharges of nuclear power plants, especially in terms of heat are restricted by a decree negotiated between the local Administration and EDF. the Paluel power plant, located on the shore of the English Channel, is one of the first units to be concerned by the expiry of its decree. In order to help the constitution of the renewing file. EDF has commissioned LNH to estimate precisely the near field of the thermal plume, as the absolute temperature at 25 m of the outlets is likely to be restricted once again by the new decree. Thermal impacts of coastal power plants are usually studied with TELEMAC-3D at time and space scales of several tides. Nevertheless, it assumes some simplifications in the near field, which can limit the accuracy of the results close to the outlets. As N3S does not exhibit these limitations, we decided to use it in order to compute precisely the flow near (and in) the outlets. The results revealed that the flow pattern is quite complex. The jet is splitted into two parts, due to the presence of a central obstacle inside the outlet. Moreover, some cold water can enter the outlet as a whirl is formed, crossing the discharge section. Nevertheless, at 25 m of the outlets, the maximal temperatures computed by N3S and TELEMAC-3D were found to be comparable, with relative heating falling to half its value. Thus, N3S and TELEMAC-3D appear to be complementary tools: N3S enabling a precise description of the near field and TELEMAC-3D being well suited for the thermal impact at the scale of the tide. A coupling could even be looked on