Four reactors at France’s Gravelines nuclear power plant, located along the English Channel, were temporarily shut down over the weekend after a swarm of jellyfish threatened to clog critical water intake systems.

Located on the Channel coast near Dunkirk, Gravelines is the largest nuclear power plant in western Europe, with six 900 megawatt reactors.

Jellyfish swarms forced a shutdown of France's largest nuclear facility at Gravelines, impacting 900-megawatt reactors but posing no safety risks to staff.