France takes nuclear reactors offline amid record heatwave

Published on

25/06/2026 - 16:37 GMT+2

France's state-owned energy giant EDF has temporarily shut down two nuclear reactors as a precautionary environmental measure, as the country grapples with a record-breaking heatwave that has already turned deadly. At least 18 heat-related deaths were confirmed in France as of Monday, and at least 40 people have drowned since June 18.

The reactors taken offline on Thursday are located at the Nogent-sur-Seine plant on the Seine River north of Paris, and at the Bugey facility on the Rhone near Lyon in the southeast. Both shutdowns were triggered by rising river temperatures, which EDF is required by law to monitor to avoid discharging water that could harm aquatic ecosystems.

Nuclear power plants use river water to cool their reactors before releasing it back into the waterway, typically at temperatures ranging from a few tenths of a degree to several degrees warmer than when it was drawn, depending on the site. During heatwaves, as rivers warm naturally, operators must cut or reduce output to stay within legally mandated discharge temperature limits.

Nogent-sur-Seine had already scaled back production on one of its reactors earlier this week "to limit the temperature increase between the water withdrawn from the Seine and the water discharged back into it, thereby protecting aquatic plant and animal life," EDF said.

A reactor at the Golfech plant on the Garonne river in southwestern France was also taken offline on Monday, with output reduced at a number of other sites across EDF's 57-reactor fleet, which together accounted for close to 70% of France's electricity generation last year.

Despite the outages, French grid operator RTE said on Wednesday that "France has sufficient generation capacity to meet electricity demand, including in the event of outages at certain production facilities."

France has placed more than half of its 96 departments under a danger-to-life red alert, urging citizens to avoid direct sunlight and exercise "absolute vigilance" as the heatwave tightens its grip. Météo-France reported that Tuesday 23 June was the hottest day recorded since measurements began in 1947.

The crisis is not limited to France. Germany, Spain, Portugal, and Switzerland are also anticipating scorching temperatures, which are starting to bring daily life to a standstill, with hundreds of schools shut or closed early and train services in cities including Paris and Brussels reduced to lower the risk of breakdowns.

This is Europe's third heatwave of the year, with forecasters warning temperatures could hit 43°C in the Mediterranean. The energy strain is already visible: in the peak days of last year's June and July heatwave, daily power demand rose by up to 14%, driving a two to three-fold increase in average daily power prices.

Scientists say the pattern is worsening. Parts of Europe are experiencing up to 40 additional days of extreme heat stress compared with the 1970s, according to a major new study.