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France's biggest nuclear plant loses to a jellyfish invasion
Four reactors at France's Gravelines nuclear power plant shut down due to jellyfish clogging cooling filters, linked to rising sea temperatures.
Four reactors at France’s Gravelines nuclear power plant were shut down late Sunday after a swarm of jellyfish clogged its cooling water filters, operator EDF said on Monday. The incident, likely linked to rising sea temperatures due to global warming, has forced a temporary halt to the entire plant’s operations.
Located in northern France between Dunkirk and Calais, Gravelines is one of the largest nuclear facilities in the country. Its six units, each producing 900 megawatts, draw cooling water from a canal connected to the North Sea. EDF data showed the remaining two reactors were already offline for planned maintenance when the jellyfish swarm hit.
Reactors 2, 3 and 4 automatically shut down just before midnight after filter drums at the pumping stations became packed with the “massive and unpredictable” influx of jellyfish, the company said. Reactor 6 followed several hours later. EDF stressed that there was no impact on the safety of the plant, staff or the environment.
Marine biologists say warming seas and invasive species are driving more frequent jellyfish blooms. “Jellyfish breed faster when water is warmer, and in areas like the North Sea, the reproductive window is getting wider and wider,” said Derek Wright, a marine biology consultant with the US National Oceanic and Atmospheric Administration Fisheries.
The Asian Moon jellyfish, native to the Pacific Northwest, was first spotted in the North Sea in 2020 and has been linked to similar disruptions at nuclear plants in China, Japan and India. The species thrives in still, plankton-rich waters like ports and canals, and can spread globally by hitching rides in ballast tanks of large vessels.
While the jellyfish near Gravelines pose no danger to humans — they lack a poisonous sting — they are yet another challenge for coastal infrastructure in a warming world. “Everyone talks about nuclear being clean, but we don’t think about the unintended consequences of heat pollution,” Wright noted.
