Hunterston B worker in the Charge Hall, November 2021. (Photo: EDF Energy)

The Hunterston B nuclear power plant has ended its nearly 46 years of zero-carbon electricity generation for Scotland with the shutdown of Unit B2. The 495-MWe advanced gas-cooled reactor (AGR), which began commercial operation in March 1977, was taken off line on January 7. The station’s companion unit, the 490-MWe AGR B1, was shut down last November.

Under an agreement with the U.K. government signed on June 23, 2021, EDF Energy, owner and operator of Britain’s power reactor fleet, is responsible for defueling all seven of the U.K.’s AGR nuclear stations over this decade. (The agreement does not include Sizewell B, which houses a 1,098-MWe pressurized water reactor slated to continue operating until at least 2035, or Hinkley Point C, which is currently under construction.) EDF expects the defueling of the AGR facilities to take from three-and-a-half to five years.

Scheduled to follow Hunterston B into the defueling phase by July of this year is the two-unit Hinkley Point B plant in Somerset, England.

Unit B1 at Scotland’s two-unit Hunterston B nuclear power plant was taken off line for good on November 26 after nearly 46 years of operation. A 490-MWe advanced gas-cooled reactor, the unit entered commercial operation in June 1976. Its companion AGR, Unit B2, which entered operation in March 1977, is scheduled for retirement in January.

Workers on the fueling machine at Hunterston B. Photo: EDF Energy

EDF Energy has received approval from the United Kingdom’s Office for Nuclear Regulation (ONR) to restart the Hunterston B power station’s Unit 3 for a limited run, according to August 27 announcements from both the company and the regulator. EDF has permission to operate the unit for up to 16.425 terawatt days (approximately six months of operation), the ONR said.

EDF also announced that Hunterston B—located in North Ayrshire, along the western coast of Scotland—will begin its defueling phase no later than January 7, 2022, more than a year earlier than the expected retirement date of March 2023. The decision, EDF said, was made following a series of executive board and shareholders meetings.