10 hours ago
- General
- The Herald Scotland
Why Torness nuclear power plant is not all it's cracked up to be
The risk of a nuclear accident is thought to be relatively high in new reactors as they are broken in. Three Mile Island and Chernobyl were both in their break-in phase when accidents occurred. Then the risk lowers in mid-life. But as reactors become older, as with any other sort of equipment, there is an increased risk of age-related failures. The Fukushima reactors began commercial operation between 1971 and 1975, so were over 40 years old when the meltdowns occurred.
Torness and Hunterston B are both Advanced Gas-cooled Reactors (AGRs) which opened in 1976 and 1989 respectively. There were an estimated 586 cracks across the two Hunterston B reactors when it was eventually forced to close in January 2022. There are a similar number of cracks in just one of the two reactors at Torness, with cracks also starting to appear in the other reactor. Cracking in the graphite core of these reactors is a problem because graphite debris could build up in the fuel channels comprising the operator's ability to keep the fuel cool and misshapen bricks could make inserting the control rods difficult. In a worst-case either of these could lead to a meltdown.
The late John Large, a nuclear engineering consultant, explained that cracks also cast doubt on the safety of these reactors in the event of an emergency like an earthquake. A cracked and deteriorating core has lost its residual strength. If the core is wobbled by a small earthquake the core could become misaligned, and the fuel modules could get stuck in the core. Then the fuel temperature would get raised and could undergo a melt. If the radioactivity gets into the gas stream and the reactor is venting because it's over pressurised then you have a release the radioactive gas into the atmosphere and you have dispersion and a contamination problem.
Pete Roche (Image: NQ) Clearly, it's time for the ageing Torness reactors to be closed. Keeping them open any longer would be gambling with public safety.
We also have to bear in mind that there is a significant design difference at Torness, compared with Hunterston, which could make the cracking problem worse. The Torness reactors have seal rings between the graphite bricks that make up the reactor core. The Office for Nuclear Regulation (ONR) says there could be 'a systematic failure' of the seal rings after cracking.
In January 2020, ONR brought forward the date when it expected to start seeing cracks appearing at Torness by six years but the closure date was only brought forward by two years from 2030 to 2028. Logically, we might have expected Torness to close in 2024. Then, in January 2024, in a bizarre switch, EDF changed its mind, and reverted to a 2030 closure date 'subject to plant inspections and regulatory approvals'.
READ MORE on the Future of Torness series:
Torness was only ever expected to operate for 30 or at most 35 years, so it is now past its sell by date. With cracks appearing in both reactors the precautionary principle dictates that it is time to shut up shop.
Jobs at Torness won't disappear immediately when the station closes. It took over three years to empty Hunterston B of fuel. After that it will take almost a century to dismantle the buildings, decommission the reactors and eradicate the radiation from the land and buildings, in fact, when Hunterston B transfers its ownership from EDF to the Nuclear Decommissioning Authority (NDA) next April, the Scottish Parliament has been told the NDA will probably need to recruit more staff to help with the decommissioning work.
As far as building new reactors at Torness, or anywhere else in Scotland, whether large or small, is concerned, that would be the last thing Scotland needs. It is perfectly feasible to supply 100% of Scotland's energy (not just electricity) from renewable sources.
Future of Torness logo (Image: NQ) In fact, a recent study by renowned energy modelling academics at the LUT University in Finland, showed that not only is a 100% renewable energy mix feasible for the whole UK but it would save well over £100 billion in achieving net zero by 2050, compared to the UK Government's current strategy.
What we need to balance variable renewables and reduce payments for turning off renewables is not always on 24/7 nuclear reactors, but more energy storage and flexibility in electricity demand. Nuclear power is too slow, too inflexible and too expensive to play a role in cutting carbon emissions.
