Torness reactor shut by seaweed

One of the two nuclear power reactors at Torness in East Lothian has been shut down today because of seaweed blocking its cooling system.

In a letter to members of the site’s local liaison council, the station’s director, Paul Winkle, said that reactor number one was turned off this morning. The reactor is meant to provide 600 megawatts of electricity for over one million homes.

The reactor was automatically tripped “due to an increase in seaweed levels as a result of the weather conditions in the area,” he wrote.

“We are currently monitoring the weather and the seaweed levels and will confirm once we have returned the unit to service.”

Winkle stressed that the problem was not new. “We know that at certain times of year particular weather conditions in this part of the Forth Estuary can lead to increased seaweed volumes which can enter the station’s cooling water intake system,” he said.

“Our staff are trained to respond in this situation, and to take the plant offline if necessary. In addition, the plant’s safety systems monitor conditions like this will take the unit offline automatically, should levels rise beyond prescribed settings, ensuring safety at all times.”

Though the closure will mean loss of power on the grid, and loss of earnings for the station’s French operators, EDF Energy, Winkle insisted it did not impact safety. “Cooling to the reactor was maintained at all times and there were no health or environmental impacts,” he said.

The second reactor at Torness is also running at low power — 272 megawatts — because of “low-load refuelling”, according to EDF’s website.

Torness reactors, sited on the coast, were previously closed by seaweed twice in 2013. They were forced to shut down in 2011 by a swarm of jellyfish. In June 2015, a reactor at EDF’s nuclear plant at Hunterston in North Ayrshire was also closed by seaweed.

Reactors need large amounts of water in order to keep them cool, and to prevent them from overheating. Seawater for cooling at Torness is filtered, but when the filters get clogged, reactors have to be shut down as a safety precaution.

Chas Booth, the Green councillor for Leith in Edinburgh, is a member of the local liaison council. The shutdown was “underlining yet again how unreliable nuclear is,” he tweeted.

The letter from EDF Energy

Photo thanks to Walter Baxter and licensed for reuse under this Creative Commons Licence.