Heatwave in France: Three nuclear reactors temporarily shut down

In addition to the three shut-down facilities, two reactors each in Saint-Alban, in Blayais, and Bugey, as well as one in Chooz, were throttled back. Seven others were throttled back. One reactor in Tricastin on the Drôme was temporarily throttled back but has been running normally again since late afternoon.

Why cooling water becomes a problem

All French nuclear reactors are located on rivers or by the sea, use the water to cool the reactors, and discharge it back into the river or sea in a warmed state. To limit damage to ecosystems, the nuclear supervisory authority ASNR sets maximum water temperature limits for each power plant.

The measures are intended to prevent too much warm cooling water from being discharged into the already warming rivers during the current heatwave. The measures are intended to prevent too much warm cooling water from being discharged into the already heated rivers.

Nuclear power as the backbone of French electricity supply

France has 57 nuclear reactors. They produce around 70 percent of the country's electricity. The shutdown and throttling of reactors during summer heatwaves is therefore a recurring issue for French energy supply.

The nuclear supervisory authority ASNR monitors compliance with the temperature limits for the discharged cooling water. As soon as river temperatures exceed certain thresholds, operators must scale back their facilities accordingly to limit the ecological consequences for fish, small organisms, and water quality.

The news was broadcast on 12.07.2026 on the Deutschlandfunk program. The information comes from the news agency AFP and was picked up by APA, among others. (AFP)