Overview
- EDF said a large influx of jellyfish entered seawater cooling pumps on Tuesday, Aug. 11, 2026, forcing automatic shutdowns and power cuts at the Gravelines site.
- Reactors 2, 3 and 4 were taken offline, reactor 1 was reduced to half power, reactor 5 was already offline for maintenance, and only reactor 6 remained at full output.
- EDF reported there was no impact on plant safety, staff safety, or the environment and did not identify the exact intake locations affected.
- Coastal reactors use seawater to cool systems so masses of jellyfish can clog intake filters and trigger automatic protections that stop reactors until pumps are cleared.
- Reporters and experts say the incident repeats a similar shutdown last year and fits a pattern of more frequent summer jellyfish blooms linked to warmer seas, which could mean rising operational risks for coastal power sites.