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Friday, 14 August 2026dailybeirut.com
Miscellaneous
French utility EDF halted three reactors at the Gravelines nuclear plant in northern France after jellyfish blocked seawater cooling pumps, while a fourth operated at half capacity and a fifth ran at full output.
Unusual marine life—not heat or drought—disrupted operations at one of France’s largest electricity generation sites. Swarms of jellyfish entered the cooling system at the Gravelines nuclear power station in northern France, obstructing seawater pumps essential for reactor cooling.
On Tuesday, French state-owned electricity company Électricité de France (EDF) announced that three reactors at the Gravelines facility had ceased operation following the jellyfish-induced blockage. A fourth reactor was scaled back to 50% of its nominal capacity. A fifth reactor continued operating at full output. The sixth reactor was already offline prior to the incident, undergoing scheduled maintenance.
EDF stated explicitly that the situation posed no safety risk to the plant infrastructure, personnel, or the surrounding environment.
The Gravelines nuclear power station is located near Dunkirk and ranks among the largest nuclear facilities in Western Europe. It houses six pressurized water reactors, each with a rated electrical output of 900 megawatts.
This incident occurred amid broader strain on France’s nuclear power generation, driven by repeated heatwaves and drought conditions across the country in 2026. EDF had previously shut down multiple reactors during June and July due to elevated ambient temperatures. According to calculations by Agence France-Presse, nuclear power output on Sunday stood approximately 15.6% below its usual level.
This is not the first time jellyfish have disrupted operations at Gravelines. A similar event occurred last year, when swarms clogged the seawater intake systems and forced a temporary shutdown of the plant.
Comparable incidents have been recorded elsewhere. In Sweden, a jellyfish accumulation led to a three-day closure of a nuclear plant in 2013. In Japan, a similar occurrence in 1999 caused a sharp drop in output at one facility.
Experts link increased jellyfish presence to several environmental factors, including overfishing, plastic pollution, and rising sea temperatures associated with climate change—conditions known to support jellyfish reproduction and population growth.
Although unexpected, the event underscores an emerging operational challenge for coastal energy infrastructure, particularly nuclear power stations reliant on seawater for cooling.
