Jellyfish Swarm Forces Partial Shutdown of Gravelines Nuclear Power Station



Gravelines nuclear power plant
Gravelines, one of France’s largest nuclear sites, is cooled from a canal connected to the North Sea.


A massive influx of jellyfish has led to the partial shutdown of the Gravelines nuclear power station, one of the country’s biggest sites operating between Dunkirk and Calais.


Two of the plant’s six units were taken offline on Wednesday and Thursday after jellyfish clogged the seawater filtration system used for cooling, EDF said.


A third unit was shut on 10 August for the same reason, and a fourth was closed for inspection. EDF now reports that units three, four and six remain offline.


Each unit at Gravelines can produce 900 megawatts of power. The franchise has experienced similar jellyfish‑related shutdowns before, including a temporary closure last August.


Jellyfish are native to the French coast and can swarm when water temperatures rise, spiking plankton levels and drawing these creatures into the plant’s cooling system.


EDF has teamed with fishermen to capture and release jellyfish further offshore, aiming to reduce future infiltration risks.


While incidents like this are uncommon, records exist of similar troubles at Scotland’s Torness plant in 2011 and Sweden’s Oskarshamn site in 2013.