About us

We are responsible for the safe and secure operation and clean-up of the Sellafield nuclear site.

Who we are

Licensed under the Nuclear Installations Act 1965 and holder of the licence for the Sellafield nuclear site, we are the legal entity responsible for Sellafield, which is owned by the Nuclear Decommissioning Authority.


We are responsible for ensuring that our activities are carried out:

  • safely, securely and predictably, with due regard for the environment
  • to the satisfaction of the Nuclear Decommissioning Authority
  • in the long-term interests of our organisation, our employees, the local communities and our supply chain partners

What we do

From cleaning-up the country’s highest nuclear risks and hazards to safeguarding nuclear fuel, materials and waste, our mission is nationally important.

Our purpose is to keep Sellafield safe and secure, cleaning-up the site to a defined end state.

We work in value streams, focusing on what we are really here to do, and prioritising what we do and how we do it to maximise value. We currently have four value streams:

  • Retrievals: we are retrieving nuclear waste, fuel and sludge that are stored inside our legacy ponds and silos, the highest risks and hazards at Sellafield
  • Remediation: beyond the legacy ponds and silos, we have hundreds of nuclear and non-nuclear facilities at Sellafield that need to be cleaned-up
  • Spent nuclear fuel management: we currently reprocess spent nuclear fuel. That means taking the fuel that has been used inside a nuclear power station and extracting the individual component parts of plutonium, uranium and waste. In future we will store fuel instead of reprocessing it
  • Special nuclear materials: we have the facilities and expertise to provide safe, secure and appropriate storage for special nuclear materials

Operating the Sellafield site also includes:

  • Nuclear waste management: we are the only organisation who can safely manage all three forms of nuclear waste: high, intermediate and low
  • Infrastructure: our day-to-day operations at Sellafield rely on the availability of a range of services, from an on-site laundry to a comprehensive rail network

How we do it

Safety and security

Keeping Sellafield safe and secure is our priority and governs the decisions that we make every day. One of the ways that we can make Sellafield safer is by removing the nuclear risks and hazards posed by our oldest building; the legacy ponds and silos.

Skills mix

Our work demands a mix of direct employment and supply chain capability. Together they are a team of more than 11,000 nuclear experts.


Innovation spans the spectrum of bespoke technology to fit-for-purpose solutions. Our supply chain partners are developing solutions for us that can be exported to other customers. We research and invest in areas with the potential to add greatest value to our mission.

Project delivery

We have a responsibility to deliver new projects at Sellafield that will support our mission. We must do this safely, securely, to the agreed specification, on schedule, within budget and with due regard to the environment.


We aim to build relationships with the Nuclear Decommissioning Authority, regulators, customers, stakeholders and the supply chain, recognising that we can achieve more together than we can alone.

Corporate centre and governance

Our governance arrangements ensure that there is a clean line of sight from the strategic decisions made by our Board to the day-to-day decisions made by our teams. Our nuclear operations are carried out in line with the appropriate regulatory authorisations and permissions.


Sellafield has been nearly 80 years in the making. A pioneer for the UK’s nuclear industry, it supported national defence, generated electricity for nearly half a century, and developed the ability to safely manage nuclear waste.

Each chapter of Sellafield’s history delivered great benefit for the country while creating a complex nuclear clean-up challenge for which there are no blueprints.

Today, Sellafield covers 6 square kilometres and is home to more than 200 nuclear facilities and the largest inventory of untreated nuclear waste in the world.

History of Sellafield

Sellafield has 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. Today we are faced with the challenge of cleaning-up the legacy of the site’s early operations, including some of the most hazardous nuclear facilities in Europe.

Munitions and nuclear deterrent

The Sellafield site has been operational since the 1940s, when it was used as a Royal Ordinance Factory supporting the war effort and the national defence programme. The factory was constructed to inspect and package small arms ammunition.

The remote nature of the site, along with its industrial workforce and experience in working for the Ministry of Supply, made it the ideal location to produce plutonium for the country’s atomic weapons programme.

Atomic age

In the 1950s, the world’s first commercial nuclear power station, Calder Hall, and the Windscale Advanced Gas-cooled Reactor were developed at Sellafield. Both were forerunners of a fleet of nuclear power stations across the country.

Commercial reprocessing

Reprocessing takes used fuel which has been removed from a nuclear reactor to recover its component parts, plutonium, uranium and waste. This process was originally used at Sellafield as part of the site’s early operations in the production of plutonium for the country’s atomic weapons programme.

In the 1970s, plans were developed to commercialise reprocessing at Sellafield and in the 1980s, construction started on a new reprocessing facility, the Thermal Oxide Reprocessing Plant (Thorp).

Nuclear waste management

Sellafield is the only nuclear site in the country that can safely manage all three forms of radioactive waste; low, intermediate and high.

  • Low level waste is compacted and sent for disposal at the national Low Level Waste Repository
  • Intermediate level waste is mixed with a grout material in engineered stainless steel drums to form a solid, stable form. This makes it suitable for long-term storage and disposal
  • High level waste is dried to a powder, mixed with glass and heated to form a molten mixture. This is then poured into stainless steel containers to solidify. The waste is then placed into a store before final disposal in the UK or return to its country of origin


We focus on three areas:

Safe, secure site stewardship

The safe and secure stewardship of the Sellafield site is our priority. It covers everything from the safety of our employees and care for the environment through to the management of nuclear materials. It underpins every decision we make.

Demonstrable progress

Sellafield is home to the oldest nuclear facilities in the UK and we are focusing our efforts on safely accelerating the clean-up of our oldest facilities. We will also demonstrate our progress through the timely completion of both the Magnox and the Thorp reprocessing programmes.

Return on investment

The Nuclear Decommissioning Authority currently invests £2 billion of its annual budget at Sellafield. We will ensure that we demonstrate value for money through the delivery of our mission.

More detail on our priorities and progress

Transforming Sellafield

Sellafield is transforming. We are preparing for the mission change and have defined the organisation we want to be in ten years’ time – how we operate internally, our size and shape, the way we work with the supply chain, and our ability to maximise wider opportunities in the future.

We are developing a high-performance, value-led organisation that reduces high hazard faster, costs the taxpayer less, and responds more quickly to potential funding changes. At the same time, we are looking for ways to maximise the socio-economic benefit from our funding and supply chain spend.

An overview of our transformation approach, phases and programmes is set out in our Transformation Plan

Corporate information

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Jobs and contracts

Read about the types of information we routinely publish in our Publication scheme.