Hunterston B defuelling marks end of an era for UK’s second-generation nuclear plants

The defuelling of the first reactor at Hunterston B nuclear power station has been completed as part of the process of decommissioning a generation of Advanced Gas-cooled Reactors (AGRs).

AGRs were the second generation of nuclear reactors to be built in the UK – the first being Magnox reactors. They use carbon dioxide as coolant and have been the backbone of the UK’s nuclear power fleet since the 1980s.

Seven AGR stations comprised of fourteen reactors (two at each station) were built between the 1960s and 1980s – Hunterston B, Hinkley Point B, Dungeness B, Heysham 1, Hartlepool, Heysham 2 and Torness.

But there are now just four reactors still operating, which are all expected to be closed by the end of the decade.

In 2020, EDF announced it would close Hunterston B the following year, two years earlier than planned, after various fractures were found in about 10 per cent of the graphite bricks in the reactor core.

The defuelling of Hunterston B’s Reactor 3 took around 16 months and work is now due to start on the station’s second reactor.

The aim is to have the second reactor defuelled and all spent fuel sent to Sellafield by mid-2025, prior to the transfer of site ownership to the Nuclear Decommissioning Authority (NDA) in 2026.

Hunterston B’s station director Joe Struthers said: “Since the station stopped generating in January 2022, the team has been completely focused on doing this job safely and efficiently, providing value for money for the UK taxpayer.

“I am delighted with the dedication shown. While defuelling is similar to the refuelling we carried out here for 46 years, the team at Hunterston B should be proud of the way they have adapted to our new mission, finding a whole new rhythm of working.”

EDF’s nuclear decommissioning director Paul Morton said: “EDF has invested more than £7bn in the UK nuclear fleet since acquisition in 2009. That investment has helped secure life extensions for these sites and maximise nuclear’s contribution to energy security.

“Now in defuelling, Hunterston B is setting the standard for the rest of the fleet and demonstrating the nuclear industry can deliver, working closely with key partners such as Sellafield, which are so crucial to the success of the defuelling programme.”

The AGR stations are currently forecast to stop generating in 2028, though EDF will continue to review lifetimes to ensure the four generating stations can continue to support the UK’s energy security for as long as it is safe and commercially viable to do so.

Over the last 50 years, the seven AGR power stations have generated more than 1,800TWh of zero-carbon electricity – enough to power every UK home for more than 16 years.

Sizewell B, the UK’s only pressurised water reactor (PWR), is due to generate until 2035, with work underway to achieve a 20-year life extension.

Three of the seven AGR stations are currently in the defuelling stage of the nuclear life cycle – Hunterston B, Hinkley Point B and Dungeness B.

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Original Source: https://eandt.theiet.org/content/articles/2023/09/hunterston-b-defuelling-marks-end-of-an-era-for-uk-s-second-generation-nuclear-plants/

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