Executive summary
Date(s) of inspection:
September 2025
Aim of inspection
ONR nuclear safeguards inspector will conduct a compliance inspection of the Sellafield Ltd. Special Nuclear Material, concentrating on the Dounreay Exotics Storage Facility (DESF) (QS40), and taking into account Finishing Line 6 (FL6) and Sellafield MOX Plant (SMP) on 10 September 2025. The purpose of this inspection is to seek evidence in support of Sellafield Ltd.’s compliance with The Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19). This inspection will be in collaboration with the Site Safety Inspector, who will be seeking evidence to support LC4 and LC32 and looking at FL6 and SMP, as well as DESF. The operator will be provided with a combined scope and agenda and separate IRs produced to highlight specific regulatory evidence for each purpose.
ONR will form regulatory judgements and provide a rating in line with ONR’s inspection rating guidance of Sellafield Ltd.’s compliance against the following Regulations in NSR19:
- Regulation 3: Basic Technical Characteristics
- Regulation 6(1-4): Accountancy and Control of Qualifying Nuclear Material
- Regulation 9: Operation of an Accountancy & Control Plan
- Regulation 10(1): Operating Records
- Regulation 11(1-4): Accounting Records
- Regulation 12(1-2): Accounting Reports
- Regulation 14: Inventory Change Reports
- Regulation 20: Weight Units and Categories of Qualifying Nuclear Material
To form effective regulatory judgements on Sellafield Ltd.’s compliance with the NSR19 regulations listed above, inspectors will consider the ONR Guidance for the Assessment of Nuclear Material Accountancy, Control and Safeguards (ONMACS) guidance and the expectations within. There will be a particular focus on:
- FSE 6 – Measurement Programme and Control
- FSE 7 – Nuclear Material Tracking
- FSE 8 – Data Processing and Control
- FSE 10 - Quality Assurance and Control for NMACS
Subject(s) of inspection
- FSE 6 Measurement Programme and Control - Rating: GREEN
- FSE 7 Nuclear Material Tracking - Rating: GREEN
- FSE 8 Data Processing and Control - Rating: GREEN
- FSE 9 Material Balance - Rating: GREEN
- NSR19 Reg03 - Declaration of basic technical characteristics - Rating: GREEN
- NSR19 Reg06 - Accountancy and control of qualifying nuclear material - Rating: GREEN
- NSR19 Reg09 - Operation of an accountancy and control plan - Rating: GREEN
- NSR19 Reg10 - Operating records - Rating: GREEN
- NSR19 Reg11 - Accounting records - Rating: GREEN
- NSR19 Reg12 - Accounting reports - Rating: GREEN
- NSR19 Reg14 - Inventory change report - Rating: GREEN
- NSR19 Reg20 - Weight units and categories of qualifying nuclear materials - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The inspection was undertaken on 10 September 2025 by the Safeguards SNM site inspector, Special Nuclear Material (SNM) Safety site inspector and a nuclear liabilities specialist and concentrated on the Dounreay Exotics Storage Facility (DESF) (QS40), and took into account Finishing Line 6 (FL6) and Sellafield MOX Plant (SMP).
The inspection targeted movements of QNM from the doner plants (including Lab L (QS51)) and was the first integrated inspection of this planning year in this area with safety to support permissioning, as listed in the Annual Safeguards Implementation Plan 2025/2026.The inspection targeted compliance against the Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19) and compliance against Licence Condition (LC) 4 (Restrictions on nuclear matter on the site) and 32 (Accumulation of radioactive waste) in respect of the Safety and nuclear liabilities. This inspection record captures evidence relevant to compliance against NSR19 and evidence relevant to LC4 and LC32 compliance is in IR-53810.
Sellafield Ltd adequately demonstrated compliance with NSR19, which included nuclear material control, accountancy system, movement and tracking of nuclear material and activities to ensure QNM is safely stored and appropriately managed.
Under LC32, which included waste inventories, storage of waste and waste audits. The site inspector identified a minor shortfall regarding the long storage of batteries and wood pallets in laydown and waste areas, due to backlog or removal across the site, and raised a Level 4 Regulatory Issue (RI-12722) to monitor the prompt removal of these items.
The inspection involved a planning phase and a one day site visit, which included discussions with relevant Sellafield Ltd personnel, review of records, sampling of information contained within electronic databases and other documentation and a plant walkdown. I sampled various training records of personnel having SQEP roles under activities supporting NSR19 such as nuclear material custodians (NMC), nuclear material accountants (NMAs), and Duly Authorised Personal in SMP and the regulatory requirements and activities carried out by the NMCs, NMAs, and DAPs (and also LC4 and LC32). From the samples, I saw evidence that the appropriate training has been completed and I judged the training to be appropriate for the roles.
Based on the sampled evidence I judge that Sellafield Ltd. is implementing appropriate and proportionate arrangements for nuclear material accountancy and control at QS40, FL6 and SMP and have met the requirements of Regulations 3, 6 (1-4) , 9, 10 (1) , 11(1-4), 12(1-2), 14, and 20 of NSR19 and ONMACSs FSEs 6, 7, 8 and 10.
Conclusion
On the basis of the evidence sampled prior to and at the time of the inspection, I found that DESF (QS40), SMP and FL6 is compliant with the safeguards arrangements for NSR19 regulations. I am satisfied that Sellafield Ltd are meeting the requirements of NSR19 and no matters requiring immediate regulatory attention were identified during this inspection. Based on the evidence provided in DESF, SMP and FL6. I judge Sellafield Ltd. is compliant with NSR19 Regulations 3, 6, 9, 10, 11, 12, 14, 20 and meets the expectations of FSE 6, 7, 8 and 10. I consider, that an inspection rating of Green (no formal action) is merited.