The Surprising Culprit That Shut Down One of the World's Largest Nuclear Reactors -- and Why It Could Happen Again

(TheBlaze/AP) -- Jellyfish are more than just a painful nuisance to beachgoers: they can damage vital infrastructure, like a nuclear reactor.

One of the world's largest nuclear reactors was a recent victim of a jellyfish attack -- and it's something marine biologists said could become more common.

In this Friday, Dec. 17, 2010 file photo, moon jellyfish are pictured in an aquarium of the Oceanographic Museum of Monaco. It wasn't a tsunami but it had the same effect: A wave of jellyfish was huge enough to force one of the world's largest nuclear reactors to shut down a phenomenon that marine biologists say could become more common. Operators of the Oskarshamn nuclear plant in southeastern Sweden had to scramble reactor number three on Sunday, Sept. 29, 2013, after tons of jellyfish clogged the pipes that bring in cool water to the plant's turbines. (AP/Lionel Cironneau)

Operators of the Oskarshamn nuclear plant in southeastern Sweden had to scramble reactor No. 3 on Sunday after tons of jellyfish clogged the pipes that bring in cool water to the plant's turbines.

By Tuesday, the pipes had been cleaned of the jellyfish and engineers were preparing to restart the reactor, which at 1,400 megawatts of output is the largest boiling-water reactor in the world, said Anders Osterberg, a spokesman for OKG, the plant operator.

All three Oskharshamn reactors are boiling-water types, the same technology at Japan's Fukushima Daiichi plant that suffered a catastrophic failure in 2011 after a tsunami breached the facility's walls and flooded its equipment.

Jellyfish are not a new problem for nuclear power plants. Last year the California-based Diablo Canyon facility had to shut its reactor two after gobs of sea salp — a gelatinous, jellyfish-like organism — clogged intake pipes. In 2005, the first unit at Oskarshamn was temporarily turned off due to a sudden jellyfish influx.

Nuclear power plants need a constant flow of water to cool their reactor and turbine systems, which is why many such plants are built near large bodies of water.

Marine biologists, meanwhile, say they would not be surprised if more jellyfish shutdowns occur in the future.

"It's true that there seems to be more and more of these extreme cases of blooming jellyfish," said Lene Moller, a researcher at the Swedish Institute for the Marine Environment. "But it's very difficult to say if there are more jellyfish, because there is no historical data."

The species that caused the Oskarshamn shutdown is known as the common moon jellyfish.

"It's one of the species that can bloom in extreme areas that ... are overfished or have bad conditions," Moller said. "The moon jelly likes these types of waters. They don't care if there are algae blooms, they don't care if the oxygen concentration is low. The fish leave ... and (the moon jelly) can really take over the ecosystem."

Moller said the biggest problem was that there's no monitoring of jellyfish in the Baltic Sea to produce the data that scientists need to figure out how to tackle the issue.

To prevent situations like this, perhaps the Korea Advanced Institute of Science and Technology's new jellyfish terminator robot (via Popular Science) could be of service.

This might look like a harmless, scientific buoy, but it's really a Jellyfish Elimination Robotic Swarm, designed to kill jellyfish in blooms that can cause economic loss. (Photo: KAIST)

The Jellyfish Elimination Robotic Swarm is autonomously run and directed toward jellyfish infestations with cameras and other technology. It sucks them into a device that will kill them. The device was developed to help reduce economic losses due to frequent infestations.

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