Office for Nuclear Regulation

Sizewell A – Inspection ID: 52568

Executive summary

Date(s) of inspection:

  • February 2023

Aim of inspection

The purpose of this inspection is to gain assurance that the arrangements within Sizewell A are compliant with the Ionising Radiations Regulations 2017 (IRR17).

Subject(s) of inspection

  • IRR17 – rating: Green

Key findings, inspector’s opinions and reasons for judgement made

This report presents the findings of a planned intervention that was undertaken to assess compliance with the Ionising Radiations Regulations 2017 (IRR17) at the Magnox Limited Sizewell A nuclear licenced site.

The intervention examined the implementation of Sizewell A’s arrangements used to secure compliance with the requirements of IRR17 through prior sampling of evidence, and discussions with key facility personnel prior to an inspection of facilities. The key requirements examined were those relating to the following IRR17 regulations and areas:

  • Regulation 8 – Radiation risk assessments
  • Regulation 9 – Restriction of exposure
  • Regulation 14 – Radiation protection adviser
  • Regulation 15 – Information, instruction, and training
  • Regulation 17 – Designation of controlled or supervised areas
  • Regulation 18 – Local rules and radiation protection supervisors
  • Regulation 20 – Monitoring of designated areas
  • Details of any IRR17 events and how these have been addressed

It is my judgement that Sizewell A site senior management and Head of Radiological Protection have demonstrated compliance with IRR17 for the regulations sampled. The Head of Radiological Protection understands the current and future radiological challenges associated with the current work, has appropriate dose monitoring mechanisms, and has been able to demonstrate those controls. I consider the documents submitted to ONR to be of a high standard. The radiation risk assessments and supporting documentation provided have confirmed input from Accredited Health Physicists prior to peer review. Where bespoke in nature, or a of high radiation dose, the Radiation Protection Advisor body of Magnox Ltd is also involved in their production.

The findings of this inspection have been shared with, acknowledged, and accepted by Sizewell A’s Head of Radiological Protection and senior management as part of normal inspection feedback.

One Regulatory Issue, 1 recommendation and 2 observations were raised.

  • The Regulatory Issue raised related to the exercising/ testing of contingency arrangements. SZA Head of RP is to develop and implement a training exercise schedule for the wider HP/RP professionals on the site. IRR17 regulation 13(2)(c) requires that ‘where appropriate, rehearsals of the arrangements in the plan are carried out at suitable intervals.’. This will be recorded as a Level 4 Regulatory Issue.
  • A recommendation (1) SZA should review and agree to identify what constitutes periodic refresher training for RPS’. In addition to this, it was recognised that SZA does not have a dedicated training team / department; SZA should review how it resources the management and coordination of all RP training onsite.
  • Observation 1 invites SZA to liaise with Magnox Corporate to produce a common Local Investigation Level (LIL)/ ALARP review template for use across the Magnox Fleet.
  • Observation 2 invites the Magnox RPA body to consider using their annual event to rotate around its fleet sites for Operational Experience (OPEX), Best Available Techniques (BAT) sharing, and wider understanding of various site challenges.

Several areas of good practice were also observed whilst undertaking this inspection. These were:

  • The quality of Radiation Risk Assessments provided to ONR to sample prior to the inspection were of a very high standard. In addition, when undertaking the site walk down, it was evident that the advice and instructions stated in the radiation risk assessments was being adhered.
  • Thematic review of RP related events allows for committee examination of cultural safety or wider root cause analysis to produce positive outcomes.
  • It was observed that the top 5% of all doses is reviewed annually. Exceeding of the LIL was not the single catalyst for dose reduction and improvement.
  • There was a high standard of the cleanliness and general ‘housekeeping’ on the SZA site.
  • The common production process of Local Rules Notices at SZA is recognised as being effective whilst containing the correct detail to enable suitable responses when dealing with an incident.
  • Coordination of cross cutting event themes have been used to improve understanding that has in turn made improvements on the site.


Overall, I have judged that, based on evidence sampled prior to and at the time of this on-site inspection, compliance with IRR17 has been demonstrated and an inspection rating of Green (no formal action) is appropriate.