France’s state-owned electricity company EDF has temporarily shut down several nuclear reactors as an unprecedented heatwave pushes river temperatures to environmentally critical levels, forcing operators to comply with strict ecological protection laws.
The precautionary shutdowns come as France battles one of the most severe heatwaves in its modern history. Authorities have confirmed at least 18 heat-related deaths, while more than 40 people have drowned since 18 June amid soaring temperatures that have affected much of the country.
The reactors taken offline are located at the Nogent-sur-Seine nuclear power station on the Seine River, north of Paris, and the Bugey nuclear facility on the Rhône River near Lyon. Both plants suspended operations after river temperatures approached legal environmental thresholds designed to protect aquatic ecosystems.
EDF said the temporary shutdowns were carried out in accordance with regulations that limit the temperature of water discharged back into rivers after being used to cool nuclear reactors.
Nuclear power stations require enormous quantities of water for cooling. River water is drawn into cooling systems before being returned to the same waterway at a slightly higher temperature. Under normal conditions, this process has minimal environmental impact.
However, during prolonged heatwaves, river temperatures naturally rise. If the discharged cooling water exceeds legally permitted limits, it can place additional stress on fish, plants, and other aquatic organisms already struggling under extreme heat.
EDF explained that one reactor at the Nogent-sur-Seine plant had already reduced production earlier in the week to minimise the temperature difference between water withdrawn from the Seine and water released back into the river.
The company stated that the decision was aimed at protecting aquatic plant and animal life while complying with environmental regulations that govern reactor operations during periods of unusually high temperatures.
Another reactor at the Golfech nuclear power station, located on the Garonne River in southwestern France, was also taken offline earlier in the week. EDF has additionally reduced electricity generation at several other nuclear facilities across its nationwide fleet.
France operates 57 nuclear reactors, making it one of the world’s largest producers of nuclear-generated electricity. Nuclear energy supplied nearly 70 per cent of the country’s electricity generation last year, making the sector central to both domestic energy security and electricity exports across Europe.
Despite the temporary reactor closures, France’s electricity grid operator RTE has assured consumers that electricity supplies remain secure.
The operator said France currently has sufficient generating capacity to meet national electricity demand, even if several nuclear facilities remain unavailable because of environmental restrictions linked to the heatwave.
Officials stressed that the country’s diversified electricity system and available reserve capacity would help prevent widespread power shortages despite reduced nuclear output.
Meanwhile, France remains in the grip of extreme weather conditions that have affected daily life across much of the country.
More than half of France’s 96 administrative departments have been placed under the highest-level red weather alert, with authorities urging residents to avoid unnecessary outdoor activities during the hottest parts of the day.
Health officials have advised vulnerable groups, including elderly people, young children, and individuals with chronic illnesses, to remain indoors, stay hydrated, and seek cooler environments whenever possible.
Météo-France reported that Wednesday, 24 June, marked the hottest day recorded since nationwide measurements began in 1947, underscoring the exceptional nature of this year’s heatwave.
The crisis extends well beyond France.
Germany, Spain, Portugal, Switzerland, Belgium, and several other European countries are also experiencing exceptionally high temperatures, prompting widespread disruptions to transport, education, and public services.
Hundreds of schools across affected regions have either closed temporarily or shortened teaching hours to protect students and staff from dangerous heat.
Rail operators in major cities, including Paris and Brussels, have reduced train services and imposed speed restrictions to minimise the risk of equipment failures caused by overheated tracks and electrical infrastructure.
Meteorologists describe this as Europe’s third major heatwave of the year, with forecasts predicting temperatures approaching 43 degrees Celsius in parts of the Mediterranean region.
The soaring temperatures are also placing additional pressure on Europe’s electricity networks.
During similar heatwaves experienced last June and July, electricity demand increased by as much as 14 per cent on peak days as households and businesses relied heavily on air conditioning and cooling systems.
The surge in consumption contributed to electricity prices rising between two and three times their normal daily averages, increasing costs for consumers and businesses alike.
Climate experts say the challenges facing France’s nuclear sector illustrate the increasingly complex relationship between climate change and energy production.
While nuclear power generates electricity without direct carbon emissions, its dependence on large volumes of cooling water makes it vulnerable during prolonged periods of extreme heat and drought.
Lower river levels and higher water temperatures can limit cooling efficiency and require operators to reduce output or temporarily suspend operations to meet environmental standards.
Scientists also warn that Europe is experiencing significantly more days of dangerous heat than in previous decades.
A recent study found that parts of the continent now experience up to 40 additional days of extreme heat stress annually compared with the 1970s, reflecting the accelerating impacts of global climate change.
Environmental researchers say rising temperatures are increasing pressure on rivers, wildlife, agriculture, public health, and energy infrastructure simultaneously, creating interconnected challenges for governments across Europe.
For France, where nuclear energy remains the backbone of electricity generation, balancing reliable power production with environmental protection is becoming increasingly important as extreme weather events become more frequent.
EDF’s decision to temporarily shut reactors demonstrates how environmental safeguards are now playing an increasingly significant role in energy management during periods of exceptional heat.
As Europe prepares for what could be another prolonged summer of extreme temperatures, policymakers, energy companies, and environmental agencies are likely to face growing pressure to adapt infrastructure and operating practices to a warming climate while maintaining secure and reliable electricity supplies.