Office for Nuclear Regulation



  • Operator/licensee: Sellafield Ltd
  • Owner: Nuclear Decommissioning Authority
  • Type of site: Decommissioning, reprocessing and nuclear waste management activities
  • Location: West Cumbria

Sellafield sites website

Sellafield - image courtesy of Sellafield Limited


Sellafield Ltd employs approximately 10,800 staff and is located on the West Cumbrian coast adjacent to the Irish Sea on the western outskirts of the Lake District National Park.

The site has been operational since the 1940s and led the development of the UK’s nuclear industry, from the production of plutonium for the country’s nuclear deterrent programme through to the development of nuclear power generation. The site is home to Calder Hall, the world’s first commercial nuclear power station which operated between 1956 and 2003. Since the closure Calder Hall and the three Windscale Reactors (Windscale Advanced Gas-cooled Reactor, Windscale Pile 1 and Windscale Pile 2) electricity is no longer generated at the site.

The focus of Sellafield Ltd is now on the remediation and clean-up of the hundreds of nuclear and non-nuclear facilities across the site; the reprocessing of spent nuclear fuel; safe and secure storage of special nuclear materials; and the safe retrieval of nuclear waste from the legacy ponds and silos, for storage in modern facilities.

Reducing the hazard and risk at Sellafield is both a national decommissioning priority and one of our top regulatory priorities.