The scourge of seaweed proved to be the downfall for reactor 3 at Hunterston on Monday evening.

In an unusual occurrence, EDF Energy confirmed that Hunterston B power station’s reactor was manually shut down at 6.40pm on Monday 1 June due to “severe seaweed ingress, accompanied by strong winds and storm surges”.

An EDF spokeswoman said: “This was done as a precautionary measure when it was clear that the seaweed levels weren’t reducing. Reactor 4 was also reduced in power and remains operating at a reduced power. We are currently monitoring the weather and the seaweed levels and when we confirm we are in a stable state we will increase power on Reactor 4 to nominal full load and also return reactor 3 to service.

“We are aware that at certain times of year with particular weather conditions in this part of the Firth of Clyde seaweed volumes can increase and enter the station’s cooling water intake system.

“Our operational staff are well trained to respond in this situation and to take the plant offline if necessary. In addition, the many-layered safety systems monitor conditions like this and the plant’s inbuilt mechanisms will take the unit offline automatically, should levels rise beyond prescribed settings, ensuring optimum safety at all times.” Cooling to the reactor was maintained at all times and there are no health, safety or environmental impacts, the energy company say.

And during the previous week, reactor 4 suffered a manual trip.

The spokesman explained: “Unit 4, Reactor 4, Turbine Generator 8 at Hunterston B power station was taken offline just after 1.30pm on Saturday 23 May following an electrical fault within the conventional power plant area, which not reactor associated. A unit refers to a reactor and one of its generating turbines. We decided to shut down the unit so we could carry out repairs. It returned to service on Thursday 28 May at 1pm.” Hunterston B power station has generated low carbon electricity since 1976 and continues to provide enough electricity for 1.7 million homes.

There is a Hunterston site stakeholders group meeting on Thursday, starting at 1.30pm at Fairlie Bowling Clubhouse. Station directors from ‘A’ and ‘B’ stations attend, as well as elected councillors. The public is welcome to attend, and ask questions.