One of the world's largest nuclear reactors was forced to shut down on Sunday when the pipes that bring in ocean water in order to cool the turbines were completely blocked by a smack of jellyfish, according to the Guardian.
Sweden's Oskarshamn nuclear power plant, located on the Baltic coast, has a boiling-water type reactor. The power plant require a steady flow of water to cool the reactor and the turbines which is why so many power plants are located near large bodies of water, the Guardian reports.
By Tuesday the plant was ready to start operating again after tons of jellyfish had been removed from the pipes. Jellyfish also forced the plant to cease operations in 2005. Lene Moller, a marine biologist for the Swedish Institute for the Marine Environment, told the Associated Press that there may be more incidents like this in the future.
"It's true that there seems to be more and more of these extreme cases of blooming jellyfish," Moller said. "But it's very difficult to say if there are more jellyfish, because there is no historical data."
A similar incident forced a power plant in California to shut down last year. Diablo Canyon atomic plant was forced to shut down their reactor when thousands of salp, a small creature similar to a jellyfish, clogged the intake pipes, according to NBC News.
"Safety being the number one priority, there was such an influx of salp and you need ocean water to cool the reactors," Tom Cuddy, a spokesman for Pacific Gas and Electric, told NBC News. "At that point we made a conservative decision to safely shut down the unit."
Common moon jellyfish were responsible for shutting down the Oskarshamn plant. The area near the plant provides a perfect ecosystem for the creature so it is expected that they may cause further shutdowns, according to the Associated Press.
"It's one of the species that can bloom in extreme areas that... are over-fished 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."
