Office for Nuclear Regulation

Dounreay – Inspection ID: 50065

Executive summary

Date(s) of inspection:

  • November 2022

Aim of inspection

This inspection is being undertaken in parallel with the safeguards Accountancy and ACP compliance inspection (IIS-50592) focussing on the DSRL ATOM system used to account for DSRLs obligated nuclear material. Therefore, this inspection will only focus on the extra aspects covered by LC4 which covers a broader scope of materials than just safeguards obligated materials. As part of this inspection ONR will form a judgement on DSRL against the requirements detailed in the Technical inspection guide on LC4 Restrictions on Nuclear Matter on the site. (LC4 – Restrictions on Nuclear Matter on the Site (

Subject(s) of inspection

  • LC4 – Restrictions on nuclear matter on the site – Rating: Green

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

Based on my interactions with DSRL nuclear material accountants, technical records officers, ATO holders, walkdowns of the DCP and D1203 facilities, alongside the discussions with my Safeguard Inspections colleagues and their findings from their concurrent Safeguards Inspection, I judge that DSRL has adequately implemented its LC4 arrangements and is adequately controlling nuclear matter on site.


Overall based on the evidence sampled during this inspection, and from the evidence sampled in IIS-50592 Safeguards Inspection, I am satisfied that DSRL has effective controls in place for nuclear matter in the areas sampled. On this basis I award them a rating of Green – Adequate.