Executive summary
Date(s) of inspection:
December 2025
Aim of inspection
ONR nuclear safeguards inspectors l conducted a compliance inspection of the Sellafield Ltd. Special Nuclear Material, Plutonium Nitrate Conversion Plant (QS25) on 3 - 4 December 2025. The purpose of this inspection was to seek evidence in support of Sellafield Ltd.’s compliance with The Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19).This inspection was in collaboration with the Site Safety Inspector, who sought evidence to support LC23, 24, 27, 28, and 34. The operator was provided with a combined scope and agenda and separate IRs produced to highlight specific regulatory evidence for each purpose.
ONR formed regulatory judgements and will 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, the inspectors considered the ONR Guidance for the Assessment of Nuclear Material Accountancy, Control and Safeguards (ONMACS) guidance and the expectations within. There was 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 10 Quality Assurance and Control for NMACS - Rating: GREEN
- FSE 6 Measurement Programme and Control - Rating: GREEN
- FSE 7 Nuclear Material Tracking - Rating: GREEN
- FSE 8 Data Processing and Control - 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: Not rated
Key findings, inspector's opinions and reasons for judgement made
The inspection was undertaken on 03 and 04 of December 2025 by the Safeguards Special Nuclear Material (SNM) site inspector, Safety site inspector, and specialist inspectors in electrical engineering, C& I and mechanical engineering, and concentrated on the Plutonium Nitrate Conversion Plant (QS25) specifically Finishing Line 4 (FL4).
The inspection targeted compliance with The Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19) and targeted compliance against License Condition (LC) 23 (Operating rules), 24 (Operating instructions), 27 (Safety mechanisms, devices and circuits), 28 (Examination, inspection, maintenance and testing) and 34 (Leakage and escape of radioactive material and radioactive waste) specifically to Finishing Line 4 (FL4) mechanical and control and instrumentation systems. This was the second integrated inspection of this planning year in the SNM area with safety to support permissioning, as listed in the Annual Safeguards Implementation Plan 2025/2026.
This inspection record captures evidence relevant to compliance against NSR19 and evidence relevant to LC23, LC24, LC27, LC28 and LC34 compliance is in IR-53812.
Sellafield Ltd adequately demonstrated compliance with NSR19, which included nuclear material control, accountancy system, movement and tracking of nuclear material and activities to ensure qualifying nuclear material (QNM) is safely stored and appropriately managed.
The inspection involved a planning phase and a two 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.
Training records were sampled for personnel performing SQEP roles under activities supporting NSR19 regulation 6(1-4), including Nuclear Material Custodians (NMC), Nuclear Material Accountants (NMAs), and Duly Authorised Persons (DAP). This also included activities carried out by the NMCs, NMAs, and DAPs relevant to LC23, LC24, LC27, LC28 and LC34. The sample provided evidence that appropriate training has been completed, and I judged the training to be appropriate for the roles.
Evidence was sampled in support of Regulation 3: Basic Technical Characteristics, Regulation 6(1-4) Accountancy and Control of Qualifying Nuclear Material, Regulation 9: Operation of an Accountancy and Control Plan and FSE 10: Quality Assurance and Control of NMACS. The Basic Technical Characteristics (BTC) were found to be in the correct template and to contain sufficient detail and arrangements for this facility type. The Accountancy and Control Plan (ACP) and its implementation were judged to be appropriate and proportionate for the activities taking place in QS25.
Accountancy reports and records were sampled, providing adequate evidence against Regulation 10(1): Operating Records, Regulation 11(1-4) Accounting Records, Regulation 12(1-2): Accountancy Reports and Regulation 14: Inventory Change Reports. Evidence relating to the repack process and the duplication of a can ID process was also reviewed and the evidence seen was judged to be appropriate and proportionate against the expectations of FSE 8: Data Processing and Control, FSE 7: Nuclear Material Tracking and FSE 6: Measurement Programme and Control.
The Safety site inspector identified minor shortfalls regarding LC28 and has raised two level 4 regulatory issues:
- Monitor the review and alignment documentation relating to maintenance (RI-12850).
- Update of the systems health report (SHR) will be monitored by Regulatory Issue (RI-12851).
- Further detail regarding the safety inspector’s information is detailed in IR-53810.
Based on the sampled safeguards evidence I judge that Sellafield Ltd. is implementing appropriate and proportionate arrangements for nuclear material accountancy and control at QS25, FL4 and have met the requirements of Regulations 3, 6 (1-4) , 9, 10 (1) , 11(1-4), 12(1-2), 14, of NSR19 and ONMACSs FSEs 6, 7, 8 and 10. Regulation 20 although listed in the scope was not rated during this inspection.
Conclusion
Based on the evidence sampled 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 QS25. I judge Sellafield Ltd. is compliant with NSR19 Regulations 3, 6, 9, 10, 11, 12, 14, and meets the expectations of FSE 6, 7, 8 and 10. Regulation 20 was not rated during this inspection although listed in the scope. I consider, that an inspection rating of Green (no formal action) is merited.