Executive summary
Date(s) of inspection
- May 2026
Aim of inspection
ONR Nuclear Safeguards Inspectors will conduct an accountancy focused compliance inspection of the Sellafield Ltd. Drum Handling and Storage Facility, Material Balance Area (MBA) QS14.6, and the Plutonium Contaminated Material Tracker (PCMT) system on the 6th and 7th of May 2026. 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).
Utilising the principles detailed in the ONR Risk Informed Targeted Engagement (RITE) policy, the MBAs have been targeted for inspection for the following reasons:
- Regulatory intelligence gathered from routine assessment of nuclear material accountancy reports submitted by Sellafield Ltd. under NSR19 Regulations 12 (1-2) and 14 indicate that the flow of Qualifying Nuclear Material (QNM) between QS06 and QS14.6 is an active flow route. As the scope of decommissioning work continues to grow on Sellafield Ltd. site, this is a key area of interest to ONR due to increased throughput of QNM and therefore increased need to adequately account for this material flow.
Regulatory intelligence gathered from routine assessment of accountancy reporting under NSR19 Regulations 12(1-2) and 14 and previous inspections has indicated the PCM flow to be an area of interest. Previous engagements have indicated accountancy using the PCMT has resulted in discrepancies.
Subject(s) of inspection
- FSE 7 Nuclear Material Tracking - Rating: GREEN
- FSE 8 Data Processing and Control - Rating: GREEN
- FSE 9 Material Balance - 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
- Overall Inspection Rating - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
ONR have targeted this intervention informed by the principles set out in the ONR Risk Informed Targeted Engagement (RITE) policy. The Plutonium Plant decommissioning areas (QS06) which send Plutonium Contaminated Material (PCM) to the Drum Handling and Storage Facility (QS14.6) at Sellafield Ltd. is an active flow route, which as the scope of decommissioning work continues to grow on Sellafield Ltd. site, will continue to increase throughput of Qualifying Nuclear Material (QNM). Further to this, previous interventions (IR-52352) and engagements, have indicated that the use of the PCM Tracker (PCMT) system has resulted in discrepancies, including misreported Material Balance Areas (MBAs) and duplicated lines within the PCMT, indicating that this should be an area of interest. As such, ONR have targeted the area to gain assurance that Sellafield Ltd. have appropriate and adequate Nuclear Material Accountancy and Control for Safeguards (NMACS) arrangements in place to enable accurate and timely statutory Nuclear Material Accounting (NMA) reporting in these areas.
This intervention sought evidence that the declared accountancy reports for the Sellafield Ltd. PCM flow between QS06 and QS14.6 are tracible and accurate to underpinning operating and accounting records. ONR sought evidence that arrangements for NMACS as described in the Basic Technical Characteristics (BTCs) for QS14.6 and QS06 and the Accountancy and Control Plans (ACPs) for QS14.6, QS06 and Sellafield site were appropriate and being adequately implemented by those with NMACS responsibilities for the MBAs. Finally the intervention sought evidence that the PCMT is fit for purpose and that suitable arrangements are in place to investigate any discrepancies when delivering its NMACS purpose.
To inform my judgements on the adequacy of the arrangements and implementation of NMACS, I utilised the Safeguards Technical Assessment Guidance (TAG) [SG-TAST-GD-001 – Issue 4], the Safeguards Technical Inspection Guidance (TIG) [SG-INSP-GD-001 – Issue 4], the Safeguards Nuclear Material Accountancy Technical Assessment Guide (TAG) [SG-TAST-GD-002, Issue 3] and safeguards expectations as described in the ONR guidance for Nuclear Material Accountancy, Control and Safeguards (ONMACS) [ONR-SAF-FW-001 – Issue 6].
I held discussions with Sellafield Ltd staff with responsibilities for NMACS, reviewed relevant operating and local instructions, and conducted an in-depth verification of source documentation used for NMACS, which underpinned the accountancy reports declared by Sellafield Ltd. under the Nuclear Safeguards (EU Exit) Regulations 2019 (2019) Regulation 14.
I noted a minor shortfall against NSR19 Regulation 14, as QNM is being double accounted for using the PCMT system. I have raised a Regulatory Issue [RI-13090] for Sellafield Ltd. to address this shortfall.
Based on the sampled evidence during the course of the intervention, I judge that there were no significant shortfalls identified during this intervention. Sellafield Ltd are adequately implementing its arrangements in line with the ONMACS Fundamental Safeguards Expectations (FSEs) 7, 8 and 9, and maintaining an appropriate system of accountancy and control for qualifying nuclear material in accordance with NSR19 Regulations 6, 9, 10, 11, 12 and 14. Based on the evidence presented, I judge that a GREEN rating is appropriate for this intervention.
Conclusion
Based on the sampled evidence, I judge that there were no significant shortfalls identified during this intervention. A single minor shortfall was noted, and I have raised RI-13090 to address this. Sellafield Ltd. are adequately implementing its arrangements in line with regulatory expectations FSE 7, 8 and 9 and maintaining an appropriate system of accountancy and control for qualifying nuclear material in accordance with NSR19 Regulations 6, 9, 10, 11, 12 and 14. I judge that a rating of GREEN is appropriate for this intervention.