Saisie des rejets thermiques par télédétection

Observation of "thermal" effluent by teledetection

Chef du Déparement Sites-Environnement-Information EDF - Direction de l'Équipement

Abstract

The most important potential environmental effects of the large number of nuclear power plants that Electricité de France ordered consists in thermal wastes. When it is possible E.D.F. uses once through cooling. In order to study the effect on environment of that kind of cooling on coastal waters (with or without tides), rivers or lakes remote sensing methods have been used, which are different for these various cases. For coastal waters a) during operations we need - a plane with a thermal sensor, - a team at sea to light heat sources on buoys, to measure water temperature at the time of the flight plus various mesurements - a team on the ground in order to know the buoys positions. b) the thermal chart is obtained from the recorded data To succeed it is necessary : - to have good meteorological conditions, - a very precise program for the 3 teams. - a constant link between the 3 teams. The errors on the maps are between 10 and 30 meters and between 0,1 °C and 0,5 °C. The first experiments took place in 1975 in Paluel after that other experiments were done for Gravelines, Flamanville and Penly (all sites in the Channel). For each site we get 3 maps (scale 1/10000) to describe the tidal effect and a larger map (scale 1/50000). For rivers Two experiments were conducted en 1977. - Rhone from St Genix to the sea, - Loire from Allier to the Ocean. The scale of the maps is 1/100000 in the flow direction and 1/20000 in the other one. With these measurements we shall be able to compare the thermal spot to the initial state and to check the numerical models.