Are animals joining the ranks of environment activists or is it global warming?
An “invasion of jellyfish” into cooling water inflow area of Scotland’s Torness nuclear power plant Tuesday led EDF Energy to shut both units there manually.
As of Wednesday, two nuclear reactors remained closed even as experts warned that such incidents may grow more common in future, Reuters reported.
Meanwhile, National Grid, U.K.’s electric power transmission network, has said that Torness reactor 1 would return to service on July 5 and reactor 2 on July 6, but plant owner EDF Energy, Britain’s largest nuclear power operator, was unable to give a restart date.
“We are working to clear the jellyfish from the waters near the power station. This work, as well as monitoring the area for more jellyfish, is ongoing,” a spokesman of EDF Energy said.
Nuclear power plants draw water from nearby seas or rivers to cool down their reactors and when it gets warm, marine animals like jellyfish tend to move inshore.
“Jellyfish can bloom in really high numbers. It’s not particularly common, [EDF Energy has] been a bit unlucky. If you get a bit of calm and warm weather they can turn up inshore in high numbers,” said David Conway, a marine biologist at the Marine Biological Association.
On Wednesday, water temperatures off the east coast of Scotland were 13 degrees Celsius (55.4 F), one degree above average levels for this time of the year, Britain’s Met Office said.
In the past, nuclear plants at Britain have rarely been obstructed by masses of jellyfish, though about three weeks ago, according to an earlier Reuters report, an Atlantic Grey Seal was rescued from EDF Energy’s Hinkley Point nuclear power station in Somerset after it got trapped in the inflow while chasing fish. Jellyfish obstruction has been more common in other countries such as Japan.
Scientists said that increased fishing activity and global warming were giving jellyfish populations a boost and nuclear power plants located near the open sea may face such situations more frequently in the coming days.
“There are suggestions from some science data that over the past few years there has been an increase in swarms of jellyfish. It’s possible it’s linked to climate change,” Steve Hay, a plankton ecologist who specializes in jellyfish research at the Marine Scotland Science laboratory in Aberdeen, told Reuters.
Overfishing of small fish which feed off jellyfish leaves them less exposed to natural predators and gives them more room to reproduce, the Marine Biological Association said, the news agency added.
On June 23, the Chugoku Electric Power Co. had to reduce the generation capacity of reactor 2 at its Shimane plant in western Japan by six percent after a pack of jellyfish partly blocked the entrance of seawater supply.