Jellyfish Swarm Overwhelms Nuclear Power Plant For The Second Time In 2 Years

Three reactors at France’s Gravelines nuclear power plant were shut down late on Monday due to a massive swarm of jellyfish, marking the second time this year the facility has faced such an issue, according to energy operator EDF. The incident occurred in northern France, near the North Sea, where the plant draws cooling water from a canal system. Gravelines is among the largest nuclear facilities in France, operating six reactors that collectively generate up to 5.4 gigawatts of electricity. Reactors 2, 3, and 4 were taken offline as a result of the jellyfish influx, while reactor 1 was restricted to 50% capacity as a precaution. Reactor 5 was already undergoing maintenance, and reactor 6 continued to operate normally. The shutdown followed similar disruptions earlier in the year, prompting EDF to introduce new preventive strategies. To address the problem, EDF has implemented fixed cameras along intake canals and on filter drum screens to detect potential blockages early. An engineer familiar with the measures explained that these systems help identify jellyfish swarms before they reach critical points within the plant. Additionally, the company has collaborated with a French fishing organization and a marine rescue group to monitor jellyfish activity and coordinate targeted trawling efforts by local fishermen. These teams were mobilized on Saturday after an initial warning was issued, helping to reduce the swarm’s density before it reached the plant. Cleanup operations are currently underway using vacuum trucks to remove jellyfish already present at the site. According to the engineer, no new jellyfish are entering the system, so the cleanup process is nearing completion. This should allow for a rapid resumption of normal operations at the affected reactors. EDF confirmed that the situation poses no risk to the safety of the facility, its personnel, or the surrounding environment. Experts suggest that such incidents may increase in frequency due to environmental changes linked to climate change. Factors such as rising ocean temperatures, the introduction of non-native species, the decline of natural predators, and overfishing are believed to contribute to more frequent and intense jellyfish blooms. Scientists have warned that these conditions could make managing such events increasingly challenging for operators like EDF. In parallel, EDF is dealing with broader challenges related to heat stress affecting nuclear reactors nationwide. A fifth heatwave is expected to intensify during the coming days, further reducing the output of France’s nuclear fleet. One reactor in the north has been offline for much of the summer due to low river levels, while another has experienced limited restarts and remained mostly inactive through July. These issues highlight the growing strain on the country’s nuclear infrastructure amid changing climatic conditions. The Gravelines incident underscores the vulnerability of large-scale industrial facilities to unexpected ecological phenomena. As jellyfish populations continue to shift under environmental pressures, operators must adapt their strategies to mitigate risks. EDF’s response, combining technological surveillance with community-based interventions, represents an evolving approach to managing such threats. The outcome of this latest disruption will likely inform future preparedness efforts, both at Gravelines and across the national grid.