Jellyfish close French nuclear power plant

• 10 days ago (2025-08-12)
• David Flin

Europe 1130 Nuclear 697

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A swarm of jellyfish caused four reactors at the Gravelines nuclear power plant in Nord, France to close, according to an announcement by the operator EDF .

EDF said that the jellyfish were found in the cooling systems of the power plant, causing an automatic shutdown late on 10 August of three reactors when the filter drums of the pumping station became packed with jellyfish. The fourth reactor shutdown automatically early on 11 August. The remaining two reactors were offline for planned maintenance at the time.

EDF said that the jellyfish did not cause damage to the facilities or the environment, but the filter pumps will be cleaned before restarting.

Gravelines has six 900 MW units, for a total combined capacity of 5.4 GW. The plant receives its cooling water from a canal connected to the North Sea.

David Wright, marine biology consultant at the National Oceanic and Atmospheric Administration Fisheries , said: “Jellyfish breed faster when water is warmer, and because areas like the North Sea are becoming warmer, the reproductive window is getting wider and wider. Jellyfish can also hitch rides on tanker ships, entering the ship’s ballast tank in one port and often getting pumped out into waters halfway across the globe.”