EDF’s Hinkley Point B, which lies on the Somerset coast, has been given the green light to start its 96-year decommissioning process by the Office for Nuclear Regulation (ONR).

The site near Bridgwater was the first advanced gas-cooled reactor to generate electricity to the grid in the UK. When it finished generating in August 2022 after 46 years of service it was the most productive nuclear power station the UK has ever had.

Since then, both reactors at the site have been defueled in advance of the site moving into its decommissioning phase.

Dan Hasted, ONR director of regulation – operating facilities directorate, said: “After careful assessment and public consultation, we are satisfied that EDF's decommissioning plans for Hinkley Point B include appropriate measures to protect people and the environment.

“We will continue to proportionately regulate the Hinkley Point B site throughout the decommissioning phase to ensure the licensee complies with applicable legislation to safeguard workers and the public.”

Decommissioning work is anticipated to start in 2026 and will take many decades to complete.

The majority of buildings, with the exception of the reactor buildings, will be demolished over a period of around 12 years. Following a long period of inactivity, around 70 years, when the reactor buildings will be maintained in a safe, dormant state, the remaining site will be decommissioned.

Reactor dismantling and site remediation for future development will be the final parts of the 96-year process.

This decision comes after a public consultation and a detailed assessment by ONR specialist inspectors of EDF’s environmental statement and Habitats Regulations Assessment.

The environmental statement included a detailed environmental impact assessment for the proposed decommissioning project at the Somerset site, along with mitigation measures designed to prevent or reduce any significant adverse environmental impacts.

The nuclear site will transfer from EDF to Nuclear Restoration Services (NRS) in due course, a subsidiary of the Nuclear Decommissioning Authority. NRS will decommission the site, which will involve dismantling and demolishing the plant and buildings as well site clearance and restoration.

Currently, NRS is responsible for safely decommissioning 13 sites across the country, including the first generation of nuclear and research sites.

Meanwhile, construction is well under way on the new Hinkley Point C plant. With two new nuclear reactors, the first in a new generation of nuclear power stations in Britain, it will provide zero-carbon electricity for around six million homes.