Safety checks are being carried out at Sizewell nuclear power station on the Suffolk coast after an automatic shutdown was triggered on Wednesday afternoon.
EDF Energy, which runs the plant, said it was an unplanned shutdown and is part of the failsafe procedure at the pressurised water reactor.
– EDF Energy spokesman
"This was an unplanned automatic shutdown. The reactor was safely shut down, with the plant responding as expected, and at no time was anyone's safety at risk. We are currently assessing the situation."
Sizewell B is one of nine nuclear sites in the UK and it normally supplies enough electricity to power two million homes.