Nuclear Power Plant Taken Down by a ‘Massive’ Swarm of Jellyfish
The pipes used to pump seawater into the reactors to cool them down were clogged with the marine animals.

Thierry Monasse/Getty Images
A large nuclear power plant in northern France has been shut down after jellyfish swarmed the pipes that draw in seawater to cool its reactors, its operator has said. The Gravelines facility, located between Calais and Dunkirk, draws seawater from a canal connected to the North Sea. EDF (Électricité de France) said a “massive and unpredictable” bloom late Sunday clogged the filter drums used to protect its cooling pumps, forcing the automatic shutdown of reactors 2, 3, and 4. Reactor 6 went offline shortly after. The remaining two reactors were already out of service for scheduled maintenance, bringing all six units offline. Gravelines produces 900 megawatts per reactor, or 5.4 gigawatts in total, making it one of France’s largest nuclear power plants. EDF said the shutdown poses no risk to the safety of the plant, its staff, or the environment. Jellyfish are common in the North Sea during warmer months, but EDF described this swarm as unusually large. The company has not said when operations will resume. The disruption comes during the summer energy demand peak, with the plant’s output temporarily removed from the national grid.
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