The Hunterston B nuclear power station in Ayrshire will be shut down earlier than planned.
Operators EDF Energy said the plant would enter the “defuelling phase” no later than January 7, 2022, to begin the process of decommissioning it.
It comes after hundreds of tiny cracks were discovered in one of its reactors in 2018 which took it out of operation for two years.
This led to a lengthy inspection and a programme of investment to repair the reactor at the site near Largs, North Ayrshire.
EDF had expected the plant to keep generating electricity through to 2023.
But the French energy giant announced Hunterston B will close around two years earlier than planned, even while the station’s reactor three has been given the green-light to begin operating again.
Hunterston B will be subject to a further inspection in spring 2021 where it will seek regulatory approval for its final six months of operation.
An EDF spokesman said: “Hunterston B has quietly delivered a major contribution to the UK for more than 40 years.
“It has far exceeded its original remit and, over its lifetime, gone on to safely produce enough low carbon energy to power the whole of Scotland for eight years.
“We didn’t know back in the 1960s, when these plants were designed, just how important low-carbon energy would become.”
Cracks had previously been found in bricks making up the core of one of its two reactors back in 2014.
Two cracked bricks were found during a planned maintenance inspection of the 6000 that make up the reactor’s graphite core.
Hunterston B began operating in 1976.
EDF also manages Scotland’s other nuclear power station at Torness, in East Lothian.
The EDF spokesman added: “Once Hunterston B stops generating power, EDF will take on the next task of defuelling the station, the first stage of the nuclear decommissioning process.
“Preparations for defuelling have been underway for a long time and, once started, the process is expected to take a few years to complete.”
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