Hunterston nuclear power station is to close down earlier than expected after several critical problems with its reactors.

The plant's French state-owned operators, EDF Energy, announced the decision to close Hunterston next year, two years earlier than previously expected.

When EDF acquired Hunterston in 2009, its expected closure date was 2016, but the company invested millions to extend its life. Now EDF is planning to run each of the station’s reactors for six months, and then, following an inspection, a final six months.

The company has ploughed over £200m into repairing the plant's reactor with the aim of continuing to produce energy until 2023 after inspectors found hundreds of cracks in the graphite core.

EDF announced today plans for the Hunterston B to move into decommissioning by January 2022 having been given approval to produce low-carbon energy for the next six months pending a further inspection in the spring.

Once the plant stops producing power it will then begin defueling, the first stage of the nuclear decommissioning process.

This is expected to take a few years and EDF said will sustain local jobs in Ayrshire making use of ‘EDF’s uniquely experienced teams, and specialist supply chain companies’.

Last year, the Office for Nuclear Regulation found that fragments and debris that had fallen off the graphite blocks of the power station had created “significant uncertainty” around the risk of blocking the channels that cool the reactor and potentially causing fuel cladding to melt.

Last week, the ONR gave Hunterston’s reactor 3 the go-ahead after the two-year investigation into its safety. But this will only be for six months.

A statement from EDF said: “This follows a major, two-year inspection and investment programme to prove that the station can respond safely to a range of earthquake scenarios, far worse than the UK has ever experienced or expects to occur.”

Simone Rossi, EDF’s UK CEO, said: “I am extremely proud of all those who have run Hunterston B for more than 40 years. Today’s announcement underlines the urgent need for investment in new, low carbon nuclear power to help Britain achieve net zero and secure the future for its nuclear industry, supply chain and workers.”

Britain’s eight nuclear power stations produce around 20 per cent of the UK’s electricity. The loss of Hunterston will leave a large gap in the country’s demand for power.

Neil Bibby MSP for West Scotland said: “While Hunterston B is restarting, the reactor will ultimately be de-commissioned from 2022. This will mean the loss of skilled jobs in an area already recording the highest unemployment levels in Scotland and it introduces new risks to security of our energy supply, with greater dependence on imported fossil fuels.

“The SNP promised 28,000 jobs in offshore wind, yet only 1700 have been delivered. We were told green jobs would reindustrialise Scotland but clearly they won’t under this SNP government.

“The de-commissioning of Hunterston B will not come as a surprise but it will still present major challenges to North Ayrshire and to Scotland. It is deeply concerning that right now the Scottish Government seem to have no credible plan for what happens next for low carbon jobs and the economy.”

Friends of the Earth Scotland's Director Dr Richard Dixon said: “Nuclear energy is dangerous, unaffordable and unreliable. For some electricity today, we are leaving a thousand generations of future humans dangerous radioactive waste. While we’d rather the reactors never restarted, having a final closure date in sight is a hugely significant step in Scotland’s transition to clean, green energy.

“The Hunterston reactors were supposed to shut nearly ten years ago and their cracked cores show that they are well past their sell-by date.

“Restarting the Hunterston reactors is definitely not worth the risk. Most people in Scotland will not even have noticed these reactors at Hunterston have been offline for most of the last two years, as the expansion of renewable energy has made up for the difference. The lights have stayed on with no problems. 

“Nuclear power leaves such a mess that there will be plenty of work cleaning up the Hunterston site for decades to come. The need to clean up afterwards is the only thing reliable about the nuclear industry.”

A Scottish Government spokesperson said: “While regulation of nuclear assets is a reserved matter, meaning it is the legal responsibility of UK Ministers, the safe operation of the remaining nuclear power plants in Scotland is an issue we take a close interest in and is a high priority for the Scottish Government.

“Hunterston B has an important role within Scotland’s secure energy supply and that of GB and it also makes a significant contribution to Ayrshire’s regional economy, but safety is of paramount importance. We note the progress achieved by EDF in addressing the strict safety requirements set out by the Office for Nuclear Regulation (ONR) on the recommencement of reactor 3 for a limited period of operation prior to its defuelling and eventual decommissioning phases.

“We will continue to engage with regulators, EDF and local stakeholders regarding the scale and nature of the impact on the Ayrshire economy following the announcement that Hunterston B will move into the defuelling phase earlier than expected - a phase of the plant’s life that has been anticipated and which will require ongoing economic activity at the site.

“Scotland’s Energy Strategy sets out our priorities for the future energy system in Scotland. This comprises a whole-system approach that promotes renewable energy generation as part of a diverse, well balanced energy supply.”