Since Sellafield opened in 1947 – as the cradle of the UK’s nuclear industry – it has been home to extraordinary partnerships and game-changing technologies.

Our legacy includes pioneering the UK’s nuclear deterrent; creating Calder Hall, the world’s first full-scale commercial nuclear power station; and, through our Windscale Advanced Gas-cooled Reactor, defining the blueprint for an entirely new family of nuclear reactors.

Our value to the UK continues to this day.

Sellafield is the only site in the country that can safely manage all forms of nuclear waste. This means we can support the wider sector by safely receiving and storing spent nuclear fuel from the UK’s fleet of power stations, helping to keep the lights on and bolstering the country’s energy security.

We are also guardians of the UK’s largest stockpile of nuclear materials and are designing new ways to reduce the environmental risk posed by our oldest facilities, including the innovating use of technology, AI and robotics.

What we do

Sellafield is the birthplace of the UK’s nuclear industry.

Scientists and engineers designed, constructed and then operated the country’s first nuclear reactors, first to create material for the atomic weapons programme and then to power the grid. Today we’re solving some of the most complex nuclear, engineering and infrastructure challenges in Europe. This is work with purpose.

1947

Construction starts on the Windscale nuclear reactors that would create nuclear materials for use in the country’s atomic weapons programme.
1950/51

The two Windscale reactors go critical.
1956

The world’s first commercial sized nuclear power station – Calder Hall – is opened by Queen Elizabeth II. The station generated electricity for the national grid and its design was copied across the country to create a fleet of Magnox power stations (so named because they used Magnox fuel).
1957

vA fire breaks out in one of the Windscale reactors. Both reactors are shutdown.
1958

Work started on the Windscale Advanced Gas-cooled Reactor. It was an experimental reactor and its design was replicated across the country to create a fleet of Advanced Gas-cooled stations all producing electricity for the national grid.
1964

We started to reprocess used Magnox fuel – a process that separated the fuel into its three component parts: plutonium, uranium, and waste.
1984

Work starts on the construction of the Thermal Oxide Reprocessing Plant (Thorp). It would go on to reprocess used Oxide nuclear fuel from around the world.
1990/91

We encapsulated the first drum of intermediate level waste, encasing it with grout in a stainless-steel drum so that it could be stored safely and securely as a solid waste.
2003

After almost fifty years of operations, Calder Hall closed.
2018

We completed our reprocessing mission in Thorp.
2021

We successfully dismantled the diffuser from the top of the Windscale chimney that was damaged in the 1957 fire.
2022

We completed Magnox reprocessing. The first batch of waste was retrieved from one of the highest hazard facilities at Sellafield, the Magnox Swarf Storage Silo.
2023

The first batch of waste was retrieved from one of the highest hazard facilities at Sellafield, the Pile Fuel Cladding Silo.