Jellyfish Swarm Shuts Three Reactors at France's Largest Nuclear Plant

A massive swarm of jellyfish has forced the shutdown of three nuclear reactors at France's largest power plant, removing 3.2 gigawatts of electricity from the national grid during a period of intense summer heat. The disruption at the Gravelines facility in northern France began on Tuesday, August 11, when tens of tons of jellyfish clogged the plant's seawater intake system, according to the operator, Electricité de France (EDF).

The emergency action forced operators to take three of the plant's six reactors offline and reduce output at a fourth reactor by half. A sixth reactor was already offline for scheduled maintenance. EDF stated that the situation had no impact on the safety of the facilities, personnel, or the environment. The shutdown occurred as temperatures across parts of France approached 104 degrees Fahrenheit, driving up electricity demand for cooling.

The Gravelines plant, located near Dunkirk, is the largest nuclear power station in Western Europe. Coastal nuclear plants rely on a continuous flow of seawater to cool their systems. When jellyfish block the pumping channels, the plant cannot cool its reactors safely. The incident marks the second consecutive year...