Jellyfish Overload Forces Partial Shutdown of France's Gravelines Nuclear Plant

Sun Sep 06 2026 03:58:22 GMT+0000 (Coordinated Universal Time)

A sudden jellyfish influx has prompted the shutdown of several units at Gravelines nuclear power station, threatening France's energy supply.

The sudden influx of jellyfish into the seawater filtration system of the Gravelines nuclear power station in northern France has forced the shutdown of several of its units. EDF confirmed that units three, four and six remain offline, while units one and two are operating at reduced power as a precaution. The incident began on 10 August following a prior wave of jellyfish, and it resumed during Wed‑Thu of this week due to worsening fouling. The plant uses a canal fed by the North Sea for cooling, and the jellyfish clog the intake filters, jeopardising efficiency. EDF has partnered with local fishermen to fish out the organisms before they reach the plant, a move similar to prior incidents at Torness (Scotland) and Oskarshamn (Sweden).

Jellyfish Overload Forces Partial Shutdown of France's Gravelines Nuclear Plant

A sudden influx of jellyfish into the seawater filtration system at Gravelines nuclear power station has forced the shutdown of several of its six units. The French electricity company EDF confirmed the partial closure amid a marine life emergency that could impact France’s power grid.

Units one and two have been operating at reduced power to mitigate the risk, while units three, four and six remain offline. The shutdown began on 10 August after a prior wave of jellyfish closed the plant last month, and it resumed on Wednesday and Thursday of this week when the fouling problem worsened.

Gravelines, one of Europe’s largest nuclear power stations, cools each 900‑megawatt unit through a canal fed by the North Sea. The superheated jellyfish, attracted by the warm waters and higher plankton from heat waves, clog the intake filters, jeopardising cooling efficiency.

EDF said authorities have set up a partnership with local fishermen to fish out the jellyfish before they reach the plant. Similar incidents have been recorded at Torness in Scotland (2011) and Oskarshamn in Sweden (2013), but they remain rare.