How Swarming Jellyfish Overran Three French Nuclear Power Reactors (sciencealert.com) 27
A "massive influx" of jellyfish forced Electricite de France SA to shut three units at its Gravelines nuclear power plant this week and reduce output at a fourth, reports Bloomberg. Just as summer temperatures surged, 3.2 gigawatts went offline — and the power utility was already facing cuts other nuclear sites as high temperatures reduced the river water available for cooling.
More details from ScienceAlert: As Politico reports, the Gravelines nuclear power plant spent hundreds of thousands of euros in 2025 to stop this happening again, only to see a repeat 12 months later... Increasing temperatures in the water can produce more of the plankton and animals that jellyfish feed on, as well as accelerating life cycles and extending breeding seasons....
It's not just jellyfish that have a habit of disrupting human energy infrastructure. Last year in Connecticut, a single raccoon caused more than a thousand power outages, as reported by CT Insider. It's not clear exactly what the raccoon did, but we do know it somehow got into a substation and caused damage to the equipment in there. The unwitting act of sabotage left more than 2,500 customers in the area without power at one stage — though repairs were swiftly carried out.
Reuters reported Tuesday on how the French utility responded to their jellyfish swarm: EDF has installed fixed cameras at the intake canals and on the filter drum screens to detect any incoming blockages as soon as possible, an engineer told Reuters... The company has also partnered with a French fishing organisation and a sea rescue organisation, which monitor for swarms and can raise an alert to launch targeted trawling operations by fishermen to reduce the swarm's density before it reaches the plant, the engineer said. The fishing boats were deployed [last] Saturday after an initial alarm was raised, limiting the impact from the swarm. The jellyfish that are already on site are being removed with vacuum trucks, he said. No new jellyfish are arriving, so cleanup is finishing, which should lead to a quick restart of the units, they added...
Scientists warn such events could become more common due to factors including global warming, the arrival of invasive species, habitat loss of predators and over-fishing.
Thanks to Slashdot reader Bruce66423 for sharing the news.
More details from ScienceAlert: As Politico reports, the Gravelines nuclear power plant spent hundreds of thousands of euros in 2025 to stop this happening again, only to see a repeat 12 months later... Increasing temperatures in the water can produce more of the plankton and animals that jellyfish feed on, as well as accelerating life cycles and extending breeding seasons....
It's not just jellyfish that have a habit of disrupting human energy infrastructure. Last year in Connecticut, a single raccoon caused more than a thousand power outages, as reported by CT Insider. It's not clear exactly what the raccoon did, but we do know it somehow got into a substation and caused damage to the equipment in there. The unwitting act of sabotage left more than 2,500 customers in the area without power at one stage — though repairs were swiftly carried out.
Reuters reported Tuesday on how the French utility responded to their jellyfish swarm: EDF has installed fixed cameras at the intake canals and on the filter drum screens to detect any incoming blockages as soon as possible, an engineer told Reuters... The company has also partnered with a French fishing organisation and a sea rescue organisation, which monitor for swarms and can raise an alert to launch targeted trawling operations by fishermen to reduce the swarm's density before it reaches the plant, the engineer said. The fishing boats were deployed [last] Saturday after an initial alarm was raised, limiting the impact from the swarm. The jellyfish that are already on site are being removed with vacuum trucks, he said. No new jellyfish are arriving, so cleanup is finishing, which should lead to a quick restart of the units, they added...
Scientists warn such events could become more common due to factors including global warming, the arrival of invasive species, habitat loss of predators and over-fishing.
Thanks to Slashdot reader Bruce66423 for sharing the news.
the headline (Score:1)
sounds like the plots of a cheap SF movie.
Re: (Score:2)
So while the US was busy training dolphins... (Score:3)
Screw the jellyfish, tell me about the racoon! (Score:2)
One racoon created 'more than a thousand power outages'??
This needs to be turned into a movie. I am OK with it being a disney cartoon, but I need to see this, preferably live action.
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He [dexerto.com] can't keep getting away with this!
Re: Screw the jellyfish, tell me about the racoon! (Score:2)
Re: (Score:2)
Re:Screw the jellyfish, tell me about the racoon! (Score:4, Funny)
Re: (Score:2)
Re: Screw the jellyfish, tell me about the racoon! (Score:2)
Unfortunately for the Raccoon Mafia's XP score, it looks like this is a relatively small town utility counting individual customers as separate outages.
I had seven power outages in my living room the other day when I tried to run the air conditioner and the iron at the same time.
Oh, just great (Score:2)
The only thing that's saved us up to this point is that jellyfish are dependent on ocean and wind currents for locomotion. But now, with mutated and improved brains, they'll probably master propulsion.
WE ARE ALL DOOMED.
Re: (Score:2)
Extreme electrical damages (Score:2)
At least it isn't cows with guns! (Score:2)
ISTM I've heard this story before (Score:2)
I think I heard this story last year, or perhaps a few years ago. I've no reason to think it was the same plant, though.
Terminology (Score:2)
The raccoon caused one power outage affecting 2500 customers.
Going to happen again. (Score:3)
2025 wasn't the first time [slashdot.org] and it definitely isn't going to be the last time. [slashdot.org]
Good (Score:3)
Yes, animals still exist, despite our best efforts.
Re: (Score:3)
I used to work in this area for a short time, so I have some insight.
The company made what the newspapers called a "fish disc", basically flashing lights and speakers placed underwater to drive fish away. There were also UV lights to stop stuff growing on them. They worked but were problematic. Difficult to install and in need of a lot of maintenance. Not 100% effective either, the nuclear plants they were protecting still needed filters and regular cleaning, just less of it. And of course when one was hit
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Oh yeah, some of those French plants shut down because the water got too warm in the heatwave.
:D because they are along fresh water rivers.
Those are not affected by the jelly fish plague
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We're having problems with fresh water jellyfish here in Western Canada. https://bcinvasives.ca/invasiv... [bcinvasives.ca]
They are small so not likely to plug up things as salt water jellyfish do
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Interesting! Thank you!
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Actually in some cases, bad, animals exist because of our worst efforts. This is one of those cases where climate change causing severe weather has once against changed animal behaviour in this case to an extent where a jellyfish bloom has occurred.
We don't celebrate all existences of plants and animals. Extensive fertiliser run-off into oceans from our farming causing blue-green algae blooms are not a good thing (they are though very much animals, bacteria specifically).
The wide spread of lionfish in the C
I knew it! Everyone said so! (Score:1)
Jelltifa!
Reminded of old SF story in Analog (Score:2)
Jellyfish that could concentrate heavy metals from the water they live in.
You would let them breed and clean up water in an area, then release a pheromone to get them to jump into your harvester ship, render them and get the contaminants.
They were released in an area with an old nuclear waste dump, so some of the stuff they were concentrating was potentially fissile.
Especially so when the pheromone told them to go up the water intakes at a power plant...