Overview
- Three reactors were taken offline and a fourth was cut to half power after a massive jellyfish influx clogged seawater intakes at Gravelines, with the operator reporting the disruption occurred on Monday and leaving only one unit at full capacity.
- EDF said the blockages did not affect plant safety, staff, or the environment and that teams expect quick restarts once intake channels are cleared.
- Cleanup work uses vacuum trucks, more frequent filter cleaning and targeted trawling by fishing vessels that were deployed after alarms, and fixed cameras installed after last year’s full outage helped detect the event.
- Scientists point to warmer seas, invasive species, loss of jellyfish predators and overfishing as drivers of larger swarms, and this episode compounds heat- and drought-related cooling limits that have already reduced French reactor availability this summer.
- The incident underscores a recurring vulnerability for coastal reactors that rely on seawater cooling and could tighten electricity supply and raise system strain if repeat events or heatwave restrictions persist.