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IAEA Integrated Regulatory Review Service (IRRS) missions to the United Kingdom

The International Atomic Energy Agency (IAEA) establishes, and globally promotes the application of its safety and security standards. 

It does this through its peer review services that are available to its Member States, which includes the UK. The Integrated Regulatory Review Service (IRRS) is one of these. It is aimed at enhancing the effectiveness of a Member State’s regulatory infrastructure for nuclear, radiation, radioactive waste and transport safety. It is commonly known as an ‘IRRS mission’.

An IRRS team is made up of technical experts, drawn from Member States, and IAEA personnel. It evaluates a state’s government, legal and regulatory infrastructure for safety. This includes the practical arrangements for regulating its nuclear facilities, activities and radiological safety against relevant IAEA safety guidance and standards

The review is not an inspection to determine compliance. It is an objective comparison of national regulation against international guidelines and standards. It makes findings that Member States act upon with the aim of enhancing regulatory effectiveness, nuclear and radiological safety. It also identifies good practices, which can be shared internationally.

The UK is a strong supporter of the IRRS and invited its first mission in 2006. This focused particularly on ONR’s preparations for regulating new reactor build. IRRS missions to the UK were also conducted in 2009 and 2013 to review new areas and to follow-up on findings from previous missions.

The IRRS uses a modular approach and most of the modules were reviewed over the course of the first three missions. Then, in 2014, an ‘Expert Mission’ visited ONR to review progress made in addressing the open findings from the previous IRRS missions.

To meet its international obligations to periodically undertake peer reviews, the UK Government formally invited the IAEA to conduct a full-scope IRRS mission in October 2019.

The mission was hosted at ONR’s offices in Bootle. For the first time, it included all regulatory bodies from the UK involved in regulating dutyholders working with ionising radiations. It also involved relevant government departments who have responsibility for policy and who sponsor the regulatory bodies.


The outcome of the peer review is published in the 2019 UK IRRS Mission Report.

In summary, for ONR, the peer review identified:

  • 1 Good Practice
  • 7 Recommendations
  • 5 Suggestions

The IRRS team comprised of 18 experts from around the world. The peer review was held over a two-week period. It involved interviews with representatives from the regulatory bodies and government departments. The IRRS team accompanied inspectors on site visits to a nuclear power plant, a hospital and a carrier transporting radioactive materials.

These recommendations and suggestions are being considered and work is ongoing to address them. The UK intends to invite the IAEA to conduct a follow-up mission within five years. A smaller team of IAEA experts will review the progress that has been made in addressing the findings and aligning with international good practice.