Sellafield: nuclear regulation

How the Environment Agency regulates discharges and radioactive waste disposals from Sellafield through environmental permitting.

The major review of Sellafield Ltd’s radioactive substances activities (RSA) permit is complete. We have issued the permit variation to Sellafield Ltd.

Sellafield nuclear site is one of the most complex and hazardous industrial sites in Europe. Activities carried out at the site include:

  • retrieving waste from old (legacy) facilities
  • cleaning up (decommissioning) redundant buildings
  • managing spent fuel, including Magnox and oxide fuel reprocessing
  • safely managing and storing nuclear materials and radioactive waste

The site is operated by Sellafield Ltd.

The Environment Agency regulates Sellafield Ltd with the Office for Nuclear Regulation.

The two nuclear regulators provide reports to the West Cumbria Sites Stakeholder Group. This is an independent body whose role is to provide public scrutiny of the nuclear industry in west Cumbria.

Find out more about how the Environment Agency regulates nuclear sites.

Regulating through environmental permits

Nuclear sites must have an environmental permit to operate. Through the environmental permitting process, the Environment Agency regulates Sellafield’s radioactive discharges to air and water, and solid radioactive waste disposals.

Environmental permits contain strict conditions (rules) an operator must follow. These conditions are designed to make sure that the operator’s activities do not harm people or the environment.

The Environment Agency sets stringent discharge limits in Sellafield Ltd’s environmental permit. It makes sure the company minimises discharges and their impacts on people and the environment.

You can ask to see a copy of Sellafield Ltd’s current environmental permits in the public register.

Reviewing Sellafield Ltd’s permits

In November 2018, radioactive fuel reprocessing ended at the Thermal Oxide Reprocessing Plant. It will end at Magnox in 2020. The focus of the Sellafield site will change from reprocessing spent fuel to decommissioning. As a result, discharges into the environment will reduce and Sellafield Ltd will need to vary (change) their permits to reflect the lower discharge levels.

The Environment Agency has been working with Sellafield Ltd to review 2 of its environmental permits to prepare for the end of fuel reprocessing at Sellafield. The permits are a RSA permit and an installation permit.

Changes to Sellafield Ltd’s RSA permit

We have just carried out a major review of Sellafield Ltd’s RSA permit. This permit controls the receipt and disposal of radioactive waste. It also sets conditions and limits on the discharges to air and water. This is the most significant review of this permit since the early 2000s.

As part of the permit review, Sellafield Ltd applied to vary (change) their RSA permit in October 2018. We consulted on this application from 26 October to 21 December 2018.

We reached a draft decision on Sellafield Ltd’s proposed changes, incorporating the comments we received from this consultation. We consulted on our draft decision from 7 October to 1 December 2019.

We reached our final decision on Sellafield Ltd’s proposed changes, incorporating comments received from both consultations. We issued the permit variation to Sellafield Ltd in February 2020. The main changes were to:

  • significantly reduce site discharge limits and introduce an upper and lower tier structure for site discharge limits
  • remove some site discharge limits where discharges have fallen below significant levels and no longer meet the Environment Agency’s criteria for setting limits
  • replace plant discharge limits with plant notification levels so that Sellafield Ltd can more effectively use the available discharge routes and treatment plants
  • remove discharge limits for the rate of fuel reprocessing (throughput) to reflect the end of reprocessing operations
  • update the permit to the latest template so that it reflects recent guidance changes

See the consultation, including the final decision document

Installation permit review

We had planned to carry out a major review of Sellafield Ltd’s installation permit alongside the review of their RSA permit. We had intended to carry out a single consultation covering both permits.

The need to review Sellafield Ltd’s installation permit is as a result of the:

  • end of reprocessing on site
  • start of post operational clean out and decommissioning activities
  • requirement for greater operational flexibility

Part of the installation permit relates to the new steam generating plant. Changes in the timeline for the steam generating plant project meant that we had to separate the 2 permit reviews. We can no longer carry out a single consultation covering both the RSA and the installation permits.

We intend to review their permit variation (to include the steam generating plant) in 2020. We will carry out a wider review of the whole installation permit after that. We have not yet agreed a specific time frame for this.

This delay has allowed us to extend the scope of the reviews to include a full review of all emission points and limits.

We will consult on any application Sellafield Ltd make to vary their installation permit. Read the public participation statement for more information about when and how the Environment Agency consults on permits.

Monitoring radiation from Sellafield

An environmental permit requires an operator to monitor radiation levels from their discharges and any effects on the environment.

Sellafield Ltd carry out environmental monitoring around the Sellafield site. The Environment Agency assesses the results and suitability of Sellafield Ltd’s programme, including the company’s monitoring for radioactive objects on west Cumbria beaches.

Find out more about:

The Environment Agency has also developed a Sellafield radioactive objects intervention plan with other organisations involved in protecting the public from radioactive objects. This plan explains how the different organisations will work together to:

  • protect the public and environment from any harm caused by radioactive objects on west Cumbria beaches
  • respond to a discovery of radioactive objects near the Sellafield site – a single find or an overall change in the find rate, activity or trends

Monitoring the environment for radioactivity around nuclear sites is also done independently by the Environment Agency and other regulators. Find out more about monitoring radioactivity in the environment.


Nuclear Regulation Group (north)

Telephone: 020 3025 5873


Published 26 October 2018
Last updated 2 March 2020 + show all updates
  1. We have removed the text: 'introduce a specific tritium limit for solid waste disposals at the on-site landfill – known as the Calder Landfill Extension Segregated Area'. This has not been implemented yet.

  2. Following public consultation, we have published our decision on changes to Sellafield Ltd's radioactive substances activities permit.

  3. Updates on the consultations about proposed changes to Sellafield Ltd's radioactive substances activities (RSA) permit. Also updated to include information about the review of Sellafield Ltd's installation permit.

  4. First published.