THE number of cracks in the core of an ageing nuclear reactor at Torness in East Lothian has risen to 46, prompting warnings that prolonging its operation would be “gambling with public safety”.
The UK Office for Nuclear Regulation (ONR) told The Ferret that the cracks were detected in April 2024 and were “at the upper end of expectations”. The first three cracks were discovered at Torness in February 2022.
ONR has previously said that spreading cracks could result in debris inhibiting the cooling of hot radioactive fuel. This can lead to a reactor meltdown, which can result in the escape of radioactivity into the environment.
In 2021, the plant’s operator, EDF Energy, said that Torness would be closed in 2028 – two years earlier than expected – because of expected cracking. The station was originally scheduled to close in 2023, and in 2016 its expected life was extended to 2030.
But in January 2024, EDF changed its mind, and announced it would review whether the plant’s life could again be extended beyond 2028 “subject to plant inspections and regulatory approvals”.
Campaigners are now worried that EDF could be putting nuclear safety at risk by trying to make more money to help deal with its “dire” finances. They are calling for Torness to be shut down “sooner rather than later”.
EDF, however, insisted that the cracks did not affect normal operations or the ability to shut down Torness in an emergency. The plant’s life would be reviewed “by the end of 2024” with the “ambition” of generating electricity after 2028.
ONR pointed out that EDF would have to demonstrate Torness would be safe to operate beyond 2028.
“We will not allow any plant to operate unless we are satisfied that it is safe to do so,” it said.
The cracks have opened up in the ring-shaped graphite bricks packed around the reactor’s highly radioactive uranium fuel. They were detected in one of the two reactors at Torness during EDF’s latest inspection on April 18, 2024.
“EDF’s sampling of fuel channels showed 46 bricks with a single full-height axial crack (a crack all the way through), which was at the upper end of expectations,” said ONR in response to freedom of information requests from The Ferret.
ONR added: “However, these observations remain within the acceptable parameters of the safety case, with risks associated with any core cracking mechanism at tolerable levels. ONR continues to have confidence in EDF’s overall understanding of the graphite core ageing mechanisms.”
According to ONR, no bricks were found with two or more cracks, though they are expected in the future. No cracks have yet been found in the core of the second reactor at Torness.
Torness Nuclear Power Station near Dunbar was officially opened in May 1989 by then Conservative prime minister Margaret Thatcher. The site had been the target of anti-nuclear protests since 1978.
Scotland’s other nuclear power station at Hunterston in North Ayrshire was closed down in January 2022, more than a year earlier than planned. This followed the discovery of an estimated 586 cracks in its two reactors.
Pete Roche, a veteran nuclear critic, pointed out that it was EDF that decided to close Torness in 2028 because of cracking.
“Given that the number of cracks are increasing, they would be gambling with public safety to now go back to a 2030 closure date,” he said.
“It’s difficult to avoid the conclusion that EDF is prepared to gamble because the plant it is building in England at Hinkley Point C is so late."
The Guardian reported in February 2024 that delays and cost overruns at Hinkley in Somerset had cost EDF £11 billion. The plant was originally due to be built for £18bn in 2017 but is now expected to cost £46bn and be completed by 2031.
According to environmental campaigner Dr Richard Dixon, Torness was “well past” its 30-year design life.
“Now the cracks are meeting the worst predictions but suddenly EDF thinks it is a good idea to run the reactors for longer,” he said.
The Scottish Greens warned of the “devastating destruction” that could be caused by poorly maintained nuclear plants.
“These reports are very worrying and should concern us all,” said the party’s co-leader and Lothian MSP, Lorna Slater.
“When it comes to something as dangerous as nuclear energy, there can be no room for error or regret. It underlines why Torness needs to be shut down sooner rather than later.”
According to EDF, 17 of the 46 cracks had been detected in inspections between February 2022 and April 2024.
Torness would play “an important role” in helping reach the new Labour government’s clean power goal by 2030, the company said.
“Nothing observed during the recent inspections affects normal operations at the site or the ability to shut the reactor down during an extreme seismic event, larger than the UK has ever recorded,” added an EDF spokesperson.
“So we intend to review reactor lifetimes by the end of 2024 with the ambition to generate zero-carbon electricity beyond the current forecast. This will be subject to plant inspections and regulatory oversight.”
ONR stressed that nuclear operators had to keep demonstrating that their plants were safe.
“If an operator wishes to extend the operating period of a reactor, they would need to provide suitable safety cases which would be considered by our expert inspectors,” said a spokesperson.
“As the independent nuclear regulator, we will not allow any plant to operate unless we are satisfied that it is safe to do so.”
ONR has also released two reports under freedom of information law showing that it approved a request from EDF allowing Torness to operate from 2024 until 2028.
In one report in June 2024, an ONR inspector noted four “shortfalls” in defects management, training, guidance and documentation, but said they were “minor” and were in the process of being addressed.
The second report from May 2024 reviewed the safety case for operating Torness until 2028 with a growing number of cracks. ONR inspectors assessed the “structural integrity” of the graphite bricks and checked their “damage tolerance”.
One inspector pointed out that the ability to shut down and cool the reactor could be affected by “core distortion” causing gaps between the graphite bricks. But the consequences were deemed “acceptable”.
The report also highlighted an “anomaly” with the damage tolerance analysis, though its effect was said to be “negligible”. Inspectors concluded that EDF had provided an “adequate” safety case.
The report also assessed “fault studies” and “external hazards”. The faults included possible impacts on the “functional capability” of the primary and secondary reactor shutdown systems, and on the arrangements for cooling hot nuclear fuel.
The assessment of external hazards focused on the dangers of earthquakes, including sudden increases in risk from increasingly severe quakes.
“EDF has provided adequate evidence to demonstrate an absence of cliff-edge effects,” the report said.
The Ferret reported in 2020 that ONR had highlighted a significant difference in the design of Torness compared to other nuclear stations. It has seal rings between the graphite bricks.
ONR quoted EDF saying that there could be “a systematic failure” of the rings after cracking.
“This could lead to debris with the potential to challenge the ability to move or adequately cool fuel,” said ONR.
If hot fuel is not cooled, it can cause a reactor meltdown, which in some circumstances can result in radioactivity leaking into the environment.
This happened during the Fukushima nuclear accident in Japan in 2011.
