A massive influx of jellyfish has resulted in the partial shutdown of a nuclear reactor at the Gravelines power station in northern France. Électricité de France (EDF) stated that two of the plant's six units were shut down on Wednesday and Thursday due to jellyfish in the seawater filtration system, which is essential for cooling.
A third unit at Gravelines has been closed since 10 August because of the same issue, while a fourth unit is currently shut for an inspection. Units three, four, and six are now confirmed to be shut. Unit three had only been reconnected to the grid on 18 August following an earlier wave of jellyfish this month, according to EDF. Units one and two are also operating at reduced power as a preventative measure.
Gravelines, located between Dunkirk and Calais in the Hauts-de-France region, was similarly affected by jellyfish in its filters last August. The station's six units each produce 900 megawatts of power and are cooled by a canal connected to the North Sea. Experts suggest that hot weather increases plankton levels, drawing jellyfish to the surface, where they are most active in warmer months.
Measures, including a partnership with fishermen to capture and release jellyfish further offshore, have been implemented to try and prevent such infiltration. Similar issues have occurred at other nuclear stations, such as Torness in Scotland in 2011 and Oskarshamn in Sweden in 2013, though such incidents are described as rare.