Inside Hunterston B (Photo: EDF Energy)EDF Energy announced that it will begin decommissioning its Hunterston B nuclear power plant in Scotland by January 2022 at the latest. The plant, which began operation in 1976, has two reactors (units 3&4, also known as B7 and B8) and had regulatory approval to operate until March 2023. However, both reactors were taken offline in 2018 after cracks were found in the graphite bricks that form the reactor core.

Hunterston 3 had been due to restart on 20 August after a number of postponements, but that was changed to 30 August. The restart date for Reactor 4 remains 17 September. “Given the age of the station and the desire to provide clarity for our staff and business partners, EDF has decided that Hunterston B will move into the defuelling phase no later than 7 January, 2022,” EDF said in a statement.

The UK Office for Nuclear Regulation (ONR) has given permission for reactor 3 to restart for six months after which time more checks will be carried out. “We… have scrutinised the nature of the cracking observed in reactor 3 and are satisfied that it will not prevent the reactor from operating safely or impede its ability to be shut down if required during this period,” said the ONR’s deputy chief inspector Donald Urquhart in a statement.

Unit 4 has operated for only six months since its closure in 2018, but is currently offline. EDF hopes to restart the reactor for a further six months from September, subject to approval. Following inspections, the ONR said there were sufficient measures in place to ensure worker and public safety for this limited time of operation.

After the existing operating period, the core will be inspected and any further period of operation would require EDF to provide a new safety case which would be assessed by ONR. This 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".

The energy company said that given the age of the Hunterston B station and the desire to provide clarity for staff, the community and business partners, EDF decided on the January defuelling. This is subject to a further inspection in spring 2021 and then regulatory approval for a final six months of operation. Preparations for defuellling have been under way for a long time and, once started, the process is expected to take several years to complete.

Photo: Inside Hunterston B (Photo: EDF Energy)