'Shut it down' demands as Torness nuclear plant breaches a safety limit

The Herald Scotland

a day ago

The Herald has seen evidence of an agreed safety case for the 37-year-old Torness nuclear power plant as of June 2022, which supported operation with up to 300 cracked bricks in a core reactor, similar to that which led to the shutting down of sister power station Hunterston B.
The plant owners' French energy firm EDF said that the safety case had been superseded by an agreed new one in May 2024, which increased the allowance to an unspecified new level in a move that echoed what happened at Hunterston B. Some have said it is "changing the goalposts".
The plant was scheduled to close in 2023, but had its life extended to 2030 in 2016. However, the planned shut down was brought forward to 2028 in 2022 as predictions over the onset of cracks were seen as more imminent.
But at the start of December, last year four power stations run by EDF had their lives extended with Torness put back to 2030 alongside and received the backing of UK energy secretary Ed Miliband who described it as a "strong endorsement of our clean power mission".
It was just three months before the extent of the cracking of Torness's Reactor 1 core was uncovered.
Cracking can destabilise the bricks leading to crucial coolants not flowing properly, which can lead to overheating, fuel damage and the risk of radiation release - the early steps of a meltdown.
It can also lead to the jamming of rods that contain the nuclear fuel, usually uranium, which could cause them to heat up controllably causing them to crack or burst releasing radioactive gases or particles.
A satellite image shows the Fukushima nuclear power plant in 2011 after an explosion.A cooling failure contributed to the meltdown disaster at the Fukushima nuclear power plant in Japan in 2011. While no-one was killed, the long-term effects of the radiation remain a matter of debate.
At the now closed sister Hunterston B advanced gas-cooled plant also owned by French firm EDF, more than 350 cracks were found in a reactor's graphite bricks when it was forced to shut down in 2018 because it was decided it could not safely operate. A second reactor was also shut down later the same year under similar circumstances.
The cracking had been in excess of an operational allowance of 350 cracked bricks.
The safety case for Torness reactors in place five years ago originally supported operation up to that which is classed as "essentially intact".
According to ONR documentation, seen by The Herald, an "essentially intact" core is defined as one with fewer than 10% cracked bricks. In Torness's 3,000 brick reactor cores that would equate to around 300 - similar to that of now shut Hunterston.
The cracking issues that caused the Hunterston shutdown affected one in every nine bricks in what was its Reactor 3 core. At the Torness nuclear plant, near Dunbar in East Lothian, it equates to one in five of the bricks of the entire core.
It has further emerged that cracks have begun to be discovered in the second of the two Torness reactor cores. In a May inspection of 13 of the estimated 330 fuel channels in the core, one brick was found to have a crack.
READ MORE on the Future of Torness series:
Sources at the regulator say that the cracks found at Torness make up a third of the bricks in a 'central area' of the reactor core which is described as the region of "greatest interest".
But EDF say that they have been able to demonstrate that the reactor cores can be operated safely with all the graphite bricks in the central part of the core cracked, including being able to shut down in the event of a major earthquake.
Three years ago, there were concerns about the safe operation of the plant when just three cracks emerged and campaigners were known to have called for it to be shut sooner from a planned closure date of 2028.
The latest concerns come as, at the end of last year, the power station operators EDF said its life would be extended to March 2030 following a full technical review. Three others would also have their lives extended.
The decision came around six months after the number of tolerable cracks in the safety case was pushed up from 300, which campaigners have described as "moving the goalposts".
That came after a UK Government-commissioned report by the energy system operator NESO found the nation would need its nuclear fleet to stay operational for longer than planned to meet Labour's goal of decarbonising the power grid by 2030.
Ed MilibandMr Miliband added: 'These extensions are a major win for our energy independence – powering millions of homes for longer while supporting 3,000 good jobs across Lancashire, Teesside, and East Lothian. We can't achieve clean power by 2030 without nuclear, which provides an all-important steady supply of homegrown clean energy."
Torness employs around 550 people with a further 180 contractors also working on site.
It began generating electricity in 1988 and was originally due to be decommissioned in 2023.
But in 2016, EDF, which said Torness generated enough electricity to power more than two million homes, would remain operational until 2030 at the earliest.
The ONR, the watchdog which is primarily funded through fees charged to the nuclear industry, say the number of cracks does not challenge the "safety margins" in the agreed safety case. They say that the reactor could still be safely shut down in an emergency.
And EDF said: 'Nuclear safety is EDF's over-riding priority, and we would not consider operating the power station unless we were confident it was safe."
But radioactivity expert Dr Ian Fairlie, who was the former head of the secretariat of the UK Government's Committee Examining Radiation Risks of Internal Emitters insisted that the levels of cracking should lead to it being closed down.
He said: "Wow. They should shut it iminently. This is a repeat of what happened at Hunterston and they had to shut that down.
"Once the integrity of the core is unreliable then really you have to close it sooner rather than later. That is what they did at Hunterston and they should do the same with Torness. It is not being anti-progress, it is about safety."
Dr Fairlie, who acts as a consultant and is a vice-president of the Campaign for Nuclear Disarmament (CND) added: "There will be lots of assurances given but to be honest with you, I don't trust it. Safety is more important than money.
(Image: NQ)
"I would argue and other environmentalists would argue that you have to adopt the precautionary principle..
"If in doubt you err on the side of caution. Protecting the public is more important than profits.
"Is it desperately important to keep a nuclear power station running? Certainly not."
He added: "You are doing a great job in shining a light on this."
In 2020, the ONR began predicting the reactors at Torness would start cracking, increasing the risk of a radioactive accident in 2022, six years sooner than had previously been thought.
An ONR inspection assessment said that EDF warned of a "systematic failure" seal rings after cracking.
'This could lead to debris with the potential to challenge the ability to move or adequately cool fuel,' said the ONR assessment.
'If keyway root cracking predictions are realised, then the safety case... is unlikely to remain robust for the next ten years periodic safety review period,' said the ONR.
At that point permission was given to keep operating until 2030 as long as checks for cracks were intensified.
EDF in 2022 consequently brought Torness's planned closure date forward by two years, to "no later than" 2028.
According to ONR records, three cracks were observed in the reactor in January 2022. But EDF said this was expected and would not on their own affect the safe operation of the power station saying there was a "safety case which was supported by the regulator.
An earlier 2020 ONR assessment said that EDF admitted, before cracks became an issue, that systematic failure of seal rings between the graphite bricks could occur after cracking and that could lead to debris with "the potential to challenge the ability to more or adequately cool fuel".
At that point, ONR said it was "aware that work is ongoing to address all potential consequences of a seal ring/brick interaction".
But it is known that campaigners once cracks started to appear, had called on the company to bring forward the closure date of Torness from 2028.
Energy consultant Pete Roche, who has been policy adviser to the Scottish Nuclear Free Local Authorities echoed the call for Torness to close.
Pete Roche (Image: NQ) He said of the latest crack numbers: "Goodness. It needs to shut. Absolutely."
He said of the expanding of the cracks tolerance level that it was changing the goalposts: "It seems to me they are stretching what is feasible with these reactors, and if they go too far we could be in trouble."
The history of the now shut Hunterston B nuclear station has run in parallel to discussions over the future of Torness.
In 2012, EDF extended Hunterston's original 25-year lifespan by more than 20 years.
But its final closure was brought forward following issues with cracks in the graphite bricks which make up the reactor cores.
The concern was that too many cracks, combined with a rare seismic event, could affect the structural integrity of the core and prevent it being shut down in an emergency.
Cracks at Hunterston were first spotted in two graphite bricks in the reactor in 2014.
Cracking issues led to its B1 reactor to be shut on March, 2018 and was back in action on August, 2020.
B2 was taken offline in October, 2018 and restarted in September 2020 after being online temporarily between August 24, 2019 and December 10, 2019.
Hunterston BBut the ONR accepted that the operational allowance should be increased from 350 to 700 cracks in each reactor.
Their life was short-lived, however. B2 was permanently shut down on January 7, 2022, after generating electricity for 46 years. B1 was closed in November, 2021.
When 359 cracks were found in B1 in the autumn of 2018, EDF insisted it was safe to operate - even though it had been shut down - and that it was planned that both reactors would be back online in the coming months.
They said then that the cracking only posed a "potential challenge to the entry of the control rod in an extreme and highly unlikely earthquake scenario" and said they had back-up systems to be able to shut down the unit.
The 480-strong workforce at Hunterston was to be cut by a quarter during eventual decommissioning and defueling but the company said those 125 employees would either retire or be redeployed to other sites.
Back in 1989, around when Torness began generating its first power, UK Government Scottish Office sources had admitted that the station constructed at a cost of £2.5bn was a mistake and should never have been built.
Friends of the Earth Scotland head of campaigns Caroline Rance said: "The enormous costs of nuclear power are due in part because so much time and money has to be spent trying to reduce the immense danger it poses. But the only real guarantee is that we'll end up with literal toxic waste that must be guarded for thousands of years.
"Scotland's nuclear power plants have a chequered safety history with serious safety lapses reported and investigations revealing hundreds of cracks in the reactor cores.
Caroline Rance "Nuclear projects are always billions over budget and desperately late. Politicians are willing to write blank cheques for the nuclear industry while people are crying out for support to insulate their homes and public transport needs upgrading.
"Climate breakdown demands an urgent move to reliable, affordable renewable energy and a real transition that supports oil workers into industries that don't harm the planet.'
The ONR said that the safety case from three years ago should not be relied upon and that in recent years, EDF had provided further justification for the safe operation of Torness with the central core containing an increased distribution of cracked bricks.
It said that experiments, computer analysis and modelling demonstrated by the EDF to the regulator has shown that the reactor core "could be safely operated and shutdown with much more widespread graphite cracking than currently seen, even in the event of a one-in-ten-thousand-year earthquake".
An ONR spokesman said: "A valid safety case is required at nuclear facilities for safe and continued operations, together with investment in plant to sustain equipment reliability, all while ensuring that the necessary people and skills are on site.
"Graphite cracking is a well-known phenomenon, and the licensee has demonstrated through their safety case that they have suitable understanding of the graphite behaviour to justify safe operation of the core.
"The number of cracked fuel bricks remain within the acceptable parameters of the safety case and we are satisfied that risks associated with any core cracking mechanism have been demonstrated to be at levels which are tolerable and as low as is reasonably practicable.
"The ongoing safety of operations at any nuclear site must be fully demonstrated to us as part of our ongoing regulation which is informed though our extensive inspection and assessment regime.
"As the independent nuclear regulator, we will not allow any plant to operate unless we are satisfied that it is safe to do so.".
An EDF spokesman added: "We are operating well inside the safety case agreed with the ONR for Torness. This includes a demonstration that the reactor cores can be operated safely with 100% of the graphite bricks in the central part of the core cracked, including shutdown in the event of a major earthquake, larger than ever recorded in the UK.
'Last year's lifetime review was rigorous and took into account recent graphite inspection results which supported the view that the station's generating life could be extended. The most recent inspection results from earlier this year were in line with our expectations meaning March 2030 is still the most likely view for Torness. As ever, our end of generation dates are a forecast based on information available at the time and are kept under review.'