A swarm of jellyfish caused officials at Paluel’s nuclear power plant to shut down one of its four reactors. The incident occurred for the second time in a month, causing the output to reduce by 2.4 gigawatts.
Electricité de France (EDF), France’s national energy firm, confirmed that the jellyfish entered the filters of the water pumping station – the non-nuclear part of the plant – and caused the disruption.
The crew at the power plant is now working to restore the reactor’s full operation.
Why does it matter?
Nuclear energy contributes to about 70% of France’s energy consumption, according to the World Nuclear Association(WNA). Paluel, based in Normandy, is the second-largest nuclear power plant in the country with a 5.2 gigawatt output. Each of its four reactors generates 1,300 megawatts of power.
Paluel is also one of the many power stations that draws seawater directly from the ocean as a coolant for its inner workings.
The power plant draws the water from the English Channel, which has warmer temperatures and ideal conditions for jellyfish reproduction.
Hence, it houses more swarms of jellyfish that can easily find their way into the water pumping station of the reactors.
The official statement
In their statement, EDF confirmed that they shut down one of the four reactors at Paluel at 9 p.m. local time on Wednesday, September 3, after jellyfish entered the pumping station.
“Production unit No. 4 was safely shut down by the operator following the arrival of jellyfish at the filters (pre-screens and filter drums) of the pumping station, located in the non-nuclear part of the facilities,” EDF said.
“These stations draw in seawater to cool the facilities. At the same time, the power of production unit No. 3 was reduced as a precaution.”
“The plant teams are mobilized and are currently carrying out the necessary diagnostics and interventions to be able to restart production unit No. 4 safely and restore full power to production unit No. 3.”
At one point, only two of Paluel’s four reactors were running at full capacity. When running at full capacity, it is also the seventh largest in the world by power output.
A history of jellyfish siege
Interestingly, this isn’t the only time jellyfish have attacked a nuclear reactor. The Gravelines nuclear power plant faced a similar problem last month, when jellyfish clogged up the cooling system to cause four of its units to switch off automatically.
In 1993, the Gravelines power plant also faced a similar situation with jellyfish.
Similar disruptions from jellyfish swarms have also affected other coastal plants, including Torness in Scotland in 2011 and Shimane in Japan, which, like France’s reactors, rely on seawater drawn directly from the coast for cooling.
Scientists have also predicted that such events could become more common due to factors such as global warming, the arrival of invasive marine species, habitat loss of predators, and over-fishing.