LONDON (Reuters) - EDF Energy, the biggest nuclear power provider in Britain, permanently switched off the second reactor at Hinkley Point B in Somerset on Monday, the company said on its website.
The 1 gigawatt (GW) plant began producing electricity for the UK grid in 1976.
Hinkley Point B has faced issues with ageing, with cracks found in graphite bricks which form the reactor's core.
The Hinkley Point B-7 reactor will soon start the defueling process which involves removing the nuclear fuel from the reactors and could take a few years, according to EDF.
The site's other reactor, B-8, was shut down last month.
After the fuel is removed both reactors will will be handed over to the Nuclear Decommissioning Authority for decommissioning.
EDF Energy is currently building a new plant, Hinkley Point C.
It is expected to start operations in 2027, a decade later than originally planned, and cost an estimated 25 billion to 26 billion pounds.
Britain is seeking to ramp up nuclear generation to account for around a quarter of all electricity by 2050, up from around 15% now.
(Reporting by Bozorgmehr Sharafedin; editing by David Goodman and Jason Neely)