Jellyfish Army Force Nuclear Power Plant Closure

It was neither a tsunami nor an earthquake. However, something quite overwhelming happened at the Oskarshamn nuclear power plant in Sweden, causing one of its three reactors to shut down. It all happened because of a huge cluster of jellyfish, a veritable army of jellyfish that forced one of the world's largest nuclear reactors to shut down last week.

Operators at the Oskarshamn plant in southeastern Sweden had to shut down reactor number three last Sunday, just after an avalanche of jellyfish clogged the pipes carrying cold water to the turbines and blocked them completely. Two days later, the pipes were cleaned and engineers prepared to restart the 1400 megawatt reactor, which is the largest boiling water in the world.

All three Oskharshamn reactors are boiling water type, the same technology as the Fukushima power plant in Japan, which suffered a catastrophic failure in 2011 after the tsunami.

Jellyfish, however, are not new problems for nuclear power plants and, according to biologists, this phenomenon tends to increase more and more. Last year, the Diablo Canyon facility in California had to shut down its reactor because of the same problem. In 2005, the first unit in Oskarshamn was temporarily shut down due to a sudden clogging of jellyfish.

Common species

Nuclear power plants need a constant flow of water to cool their reactor and turbine systems. This is why many of these structures are built near high concentrations of water and, according to biologists' assessment, this phenomenon that has happened may become increasingly common.

The species that caused the Oskarshamn shutdown is known as the moon jellyfish, a fairly common type. "It's one of the species that can come up in extreme areas. She likes these types of waters and doesn't care if there is algae bloom or oxygen concentration is low. Fish fade and these jellyfish can really take over the ecosystem, " Lene said. Moller, a researcher at the Swedish Institute for the Marine Environment at The Huffington Post.

Moller said the biggest problem is that there is no specific monitoring of jellyfish in the Baltic Sea, which could produce the data scientists need to figure out how to solve these events.