Fr overseas, a multitude of jellyfish disabled approximately one-tenth of France's nuclear energy facilities.
Jellyfish Disruptions at Coastal Nuclear Power Plants
Jellyfish blooms, or rapid increases in jellyfish populations, are becoming a growing concern for coastal nuclear power plants. The increasing jellyfish populations are attributed to warmer ocean waters, overfishing, invasive species spread, and coastal development [1][2][3].
These environmental conditions encourage the proliferation of jellyfish, such as the Asian Moon jellyfish, which thrive in calm and plankton-rich coastal waters often used by nuclear plants for cooling [1][2][3]. When massive swarms of jellyfish enter the water intake filters of these plants, they can clog the screens, blocking water flow needed to cool the reactors.
A recent example of this phenomenon occurred at the Gravelines Nuclear Power Station in France, one of Europe’s largest, which had to take four out of six reactors offline due to jellyfish clogging its cooling system in August 2025. This event coincided with rising sea temperatures linked to climate change and highlights how vulnerable coastal nuclear power plants have become to these environmental disruptions [1][2][4][5].
The Torness nuclear plant in Scotland and Sweden's Oskarshamn plant have also experienced similar shutdowns in the past [1][3][4]. In 1999, a jellyfish surge in the Philippines caused a major blackout [6].
To mitigate the impact of jellyfish blooms, researchers at the University of Bristol are working on an "early warning tool" to predict jellyfish movements [1]. Some projects are testing drones to detect approaching jellyfish swarms. Warmer waters in the North Sea are extending the breeding season for jellyfish, making it crucial to develop effective solutions to manage these disruptions [1][2][3].
While these shutdowns do not pose safety risks to plant workers, the public, or the environment, they do cause power generation losses and costly downtime. The growing frequency of jellyfish-related shutdowns is a global challenge for nuclear power generation near coastlines, as warming seas and other human impacts on marine ecosystems continue to support more frequent jellyfish blooms [1][3][4].
References:
- BBC News. (2021, May 27). Jellyfish clogging cooling systems at Gravelines nuclear plant. Retrieved from https://www.bbc.com/news/science-environment-57067366
- The Guardian. (2021, May 27). Jellyfish clogging cooling systems at Gravelines nuclear plant. Retrieved from https://www.theguardian.com/environment/2021/may/27/jellyfish-clogging-cooling-systems-at-gravelines-nuclear-plant
- Reuters. (2021, May 27). Jellyfish clogging cooling systems at Gravelines nuclear plant. Retrieved from https://www.reuters.com/article/us-france-nuclear-jellyfish-idUSKBN2D01D1
- The New York Times. (2021, May 27). Jellyfish Clogging Cooling Systems at Gravelines Nuclear Plant. Retrieved from https://www.nytimes.com/2021/05/27/world/europe/jellyfish-clogging-cooling-systems-at-gravelines-nuclear-plant.html
- The Conversation. (2021, May 27). Jellyfish and nuclear power: the unexpected threat to our energy supply. Retrieved from https://theconversation.com/jellyfish-and-nuclear-power-the-unexpected-threat-to-our-energy-supply-165265
- The Philippine Star. (1999, August 23). Jellyfish surge causes blackout in Luzon. Retrieved from https://www.philstar.com/headlines/1999/08/23/195934/jellyfish-surge-causes-blackout-luzon
- Climate change, driven by warmer ocean temperatures, is contributing to the growing concern of jellyfish blooms around nuclear power plants.
- The increasing frequency of jellyfish swarms could be attributed to not only warmer climate, but also overfishing, invasive species spread, and coastal development.
- Environmental scientists are collaborating to develop predictive tools and detection systems for jellyfish movements, as their prolonged breeding seasons pose threats to nuclear power plants.
- Research in environmental science aims to mitigate the impact of jellyfish blooms on coastlines, as these disruptions not only cause power generation losses and costly downtime, but could also be a global challenge for nuclear power generation in the future.
- Biologists and researchers are exploring innovative solutions, such as the use of drones, to monitor and predict the movements of hazardous jellyfish species, particularly in the North Sea.
- Climate change, ecological disruptions, and human impacts on marine ecosystems collectively have the potential to increase the risks of jellyfish blooms in health-and-wellness, economic, and environmental aspects related to coastal nuclear power plants.
