French nuclear power plants forced to cut output due to heat

French energy company EDF has cut output at its nuclear power plants by several gigawatts due to a heatwave. The company also warned of further cuts through next Monday.

Many French nuclear power plants use river water to cool their reactors. EDF is legally required to reduce output when river water temperatures are high or river flows are low. On Sunday, temperatures in southwestern France reached 41 °C, according to the weather service Meteo France.

EDF announced last week that it would limit the available capacity of the Bugey, St. Alban and Tricastin nuclear power plants on the Rhône River, as well as the Golfech plant on the Garonne River.

EDF first announced on Thursday that it would cut the plants’ combined output by 10 GW for the week starting last Friday. On Friday, the company revised the cuts to a combined 8.4 GW, saying it would update the plants’ available capacity for each day.

Since Sunday, EDF has reduced output at the Bugey 2 plant, which has an installed capacity of 910 MW, to 647 MW. From 5 p.m. tomorrow, the plant will be completely shut down for 24 hours. Output at the St. Alban 2 plant, with an installed capacity of 1 335 MW, was limited to 260 MW for eight hours on Sunday and yesterday.

EDF also planned to reduce output at its Tricastin 2 and 4 units (each 915 MW) to 180 MW for several hours today. Meanwhile, Golfech 1 cut its output from 1 310 MW to 280 MW from 2 p.m. until Wednesday, while the plant’s second reactor will remain shut down to save fuel until August 26.