(Montel) French utility EDF warned on Wednesday of potential output cuts of up to 3.8 GW at its nuclear power plants Tricastin, St Alban and Golfech due to high temperatures in the Rhone and Garonne rivers.
However, the firm added it needed to maintain minimum capacity – 1,400 MW – at the units to ensure security of supply but did not say how long the production curbs would last.
Southern France is facing a new hot spell with temperatures expected to reach 40C over the next two days, according to the forecaster Meteo France.
EDF is often forced to curb power production at its units during the summer and autumn as they use water from the rivers to cool their reactors but cannot if it becomes too hot or flows are too weak.
After the 2003 heatwave, the ASN nuclear safety authority set temperature limits – at 28C for most rivers – and river flow limits, beyond which the plants must reduce their production.
France’s environmental code allows EDF to raise the temperature limit to a maximum of 3C under “exceptional situations”.