Executive summary
Date(s) of inspection:
March 2026
Aim of inspection
The NRS Hunterston A site has been selected for an IRR17 Public Exposure inspection because the current radiation doses (2024) to the most exposed member of the public are above the ONR Basic Safety Objective (BSO) 20 micro sieverts per annum, Safety Assessment Principle (SAP). The Ionising Radiations Regulations 2017 (IRR17) Regulation 12(3) introduces a duty on employers to estimate doses to members of the public, in addition to the duty to restrict exposures under Regulation 9.
Subject(s) of inspection
- IRR17 - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The purpose of this inspection was to evaluate Nuclear Restoration Services Ltd’s arrangements at Hunterston A for complying with the Ionising Radiations Regulations 2017, Regulations 9 and 12, Restriction of Exposure and Dose Limitation, specifically in regard to members of the public.
This was the second of two planned ‘Direct shine and other pathways’ inspections during 2025-26 in support of the Office for Nuclear Regulation Technical (Decommissioning Fuel and Waste) sub-division strategy.
The inspection was undertaken and rated against published guidance on regulatory expectations, as set out in IRR17 ACoP and Guidance (L121). Based on the evidence sampled at the time of the intervention against Nuclear Restoration Services Ltd Hunterston A’s arrangements, ONR judged that Nuclear Restoration Services Ltd demonstrated adequate compliance with the Ionising Radiations Regulations 2017 Reg 9 and 12.
Conclusion
I noted that all the weather resistant cases for the dosimeters at the survey point locations were in adequate condition (apart from TLD P08).
I noted that the background dose rate for the NRS HNA was obtained from off-site measurements. I consider this an adequate method to obtain the representative background radiation dose for the annual return.
I noted that the site plans to remove milk inclusion in future dose assessment methodology as there is no milk production in the immediate vicinity of the site. I am content with the removal of milk from the assessment methodology.
Overall, I am satisfied that public exposure due to direct radiation and other pathway exposure from the site is reduced to as low as reasonably practicable.
The sites exceeded the BSO but did not exceed the UKHSA recommended dose constraint of 0.3 mSv nor the Basic Safety Limit (BSL) and IRR17 legal limit for direct radiation and other pathways exposures combined.
I judged NRS HNA implementation of IRR17 Regulation 12 (3) arrangements to be adequate to reduce doses to the public from the site operations in the areas inspected and I assign a rating of GREEN.