France's heatwave, with temperatures of up to 43 degrees Celsius, is expected to force several of the country's nuclear power plants to reduce output, with state energy company EDF cutting production at the Golfech plant in the south of the country on Monday night.
EDF also announced operational restrictions at three further plants on Tuesday. The reason was the rising water temperature in the rivers from which cooling water is drawn, EDF said.
The measures are intended to prevent the temperature in the rivers from exceeding set limits when the heated cooling water is discharged back into them.
In addition to Golfech, restrictions could also affect the Blayais nuclear plant, also located on the Garonne, EDF said. Restrictions are also being considered for the Bugey and Saint-Alban plants on the Rhône.
According to EDF, the impact of the measures on electricity production is negligible. Throttling or shutting down nuclear plants during heatwaves has led to a reduction in annual electricity output of an average of 0.3% since 2000. However, if heatwaves become more frequent and intense, the impact could be greater.
France experiences hottest night since records began
France experienced its hottest night in decades, with the national temperature indicator reaching its highest level since records began in 1947, the state weather service Météo France said on Tuesday.
The national temperature indicator - an average of 30 reference weather stations on the French mainland - reached 21.6 degrees Celsius, according to preliminary data.
The heatwave continues to spread across the country. At midday, 54 French regions were under the highest weather warning level, red. Never before, since the warning system was introduced just over 20 years ago, had so many areas been simultaneously affected by such a heat warning.
France has been groaning under enormous heat since Thursday, with temperatures climbing to as high as 43 degrees in places.
The authorities have described it as an exceptionally severe heatwave. There is no sign yet of when people can expect relief.
Some schools have closed and in some cases school-leaving exams have been postponed. According to Prime Minister Sébastien Lecornu, 40 people have drowned in the country since Thursday, many of them minors.
