The energy company, EDF, is planning to operate a cracked and ageing nuclear power station at Hunterston in North Ayrshire for another year before closing it down for good.
The company is hoping to restart the two 44-year-old reactors at the site for two last six-month periods and then begin decommissioning them “no later than 7 January 2022”. The reactors were previously scheduled to be shut down in March 2023.
The UK government’s Office for Nuclear Regulation (ONR) has given permission for reactor three at Hunterston to restart and run for six months. But it has yet to allow reactor four to run for another six months, or either reactor a second six months of operation.
Local authorities and campaigners have condemned the moves to restart Hunterston, warning that public heath is being put at risk. They are calling for the plant to be permanently closed down now.
EDF, however, insists that the reactors can be operated for another year to produce low-carbon electricity. They could be safely shut down if disrupted by earthquakes, it says.
Reactor three at Hunterston B has an estimated 377 cracks in its graphite core and has been shut down since 9 March 2018. After a two and a half year investigation, ONR has now given permission for it to restart.
But the reactor will only be allowed to operate for six months before it will have to close down again so that its core can be checked for new cracks. Then EDF said it will bid to operate it for a further, final six months.
Reactor three is the oldest reactor of its kind in the UK, and started generating electricity in 1976. It was originally due to be closed down in 2006, but that was postponed to 2016 and then to 2023.
Reactor four at Hunterston has an estimated 209 cracks in its core, and was shut down on 2 October 2018. It was allowed to restart for four months in 2019, and is now awaiting permission from ONR to start up again.
EDF’s board decided on 27 August 2020 to bring forward the planned date for Hunterston’s final shutdown from 2023 to January 2022 or sooner “given the age of the station”.
The 50-strong group of Nuclear-Free Local Authorities in the UK demanded that both reactors never re-open. “The safest thing to do is to close Hunterston B and start accelerated decommissioning of its reactors,” said the group’s Scottish convener, Glasgow SNP councillor Feargal Dalton.
“We totally disagree with EDF that decommissioning should start in 2022. It should happen now for the sake of public safety.”
He added: “The fact it has taken two years and much resource from EDF to provide sufficient information to the ONR to allow a restart to take place is indicative of the level of risk over the structural integrity of these reactors.”
Hunterston reactors ‘past their sell-by date’
According to Friends of the Earth Scotland, the reactors were “well past their sell-by date”. Their electricity was not needed and could be better provided by renewables, it argued.
“Restarting the reactors is definitely not worth the risk,” said the environmental group’s director, Dr Richard Dixon. “Nuclear energy is dangerous, unaffordable and unreliable.”
He pointed out that reactors left radioactive waste that was dangerous for many thousands of years. “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,” he said.
“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.”
The Scottish Greens also called for Hunterston to stay closed. “Turning reactor three back on for six months is a completely unnecessary risk,” said Ross Greer, the Green MSP for the west of Scotland.
“This is EDF squeezing as much profit out of the site as they can. It’s certainly not about meeting our national energy needs, given both Hunterston reactors have been offline for prolonged periods of time without the lights going out.”
The Edinburgh-based nuclear critic and consultant, Peter Roche, argued it was “crazy” to restart the reactors. A nuclear reactor in England had been closed because of a surplus of electricity during the coronavirus pandemic, he said.
“They people of Ayrshire are clearly being used as guinea pigs by EDF so they can keep their other six ageing reactors across the UK limping along as long as possible because the company has been in such a financial pickle long before the virus hit,” he added.
EDF said that approval to restart reactor three followed “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.”
A company statement added: “Hunterston B will move into the defuelling phase no later than 7 January 2022. This is subject to a further inspection in spring 2021 and then regulatory approval for a final six months of operation.”
The company said defuelling would take “a few years” and was only the first stage of the decommissioning process. It was talking to its 500 staff at Hunterston, and expecting some to retire, some to stay working there and some to move to other sites.
EDF’s managing director for generation, Matt Sykes, said: “Our focus is on continuing to safely deliver the last period of power generation and then transition the station into decommissioning.
“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.”
The Office for Nuclear Regulation said that its decision to allow reactor three to run for another six months followed “an extensive and detailed assessment” of the safety case put forward by EDF.
“ONR’s assessment has focussed on whether cracking observed in the graphite bricks that form the reactor core of reactor three could compromise its fundamental nuclear safety requirements,” said ONR.
These included ensuring that the control rods which shut down the reactor would be “unimpeded”, and “ensuring that gas flow will be maintained to ensure cooling of the fuel and core.”
ONR inspectors concluded that EDF had made an “adequate” case for restarting the reactor. “We are satisfied that reactor three is safe to operate for the next period and could be safely shutdown – including in a significant seismic event, such as an earthquake – if required,” ONR said.
“Our inspectors are satisfied that there are sufficient safety margins and defence in depth measures in place to ensure public and worker safety throughout the further period of operation.”
ONR’s deputy chief inspector, Donald Urquhart, added: “We have scrutinised the nature of the cracking observed in reactor three and are satisfied that it will not prevent the reactor from operating safely or impede its ability to be shutdown if required during this period of operation.
“As the independent nuclear regulator, our sole priority is the safety of site workers, local residents and the wider public who rely on ONR to regulate such safety matters. We will only allow nuclear facilities to operate if we are satisfied that they are safe to do so.”
The Ferret reported in October 2019 that the graphite cores of the two Hunterson reactors had begun to crumble because of the cracking. Technical reports released by ONR revealed that at least 58 fragments and pieces of debris had broken off.
ONR said at the time that there was “significant uncertainty” about the risks of debris blocking channels for cooling the reactor and causing fuel cladding to melt. This could cause an accident and a leak of radioactivity.
We also revealed in May 2020 that the ONR was predicting that cracks would start appearing at Torness nuclear power station in East Lothian in 2022 – six years sooner than previously thought.
Photo thanks to EDF.