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Sellafield - Inspection ID: 52352

Executive summary

Date(s) of inspection: October 2023

Aim of inspection

The Office for Nuclear Regulation (ONR) Safeguards subdivision inspection and assessment activities seek assurance of Operator’s compliance with relevant domestic legislation and international agreements described in ONR Safeguards strategy and guidance. This record captures the outcome of a planned safeguards system-based inspection (SSBI) on the Sellafield nuclear licensed site in Cumbria, operated by Sellafield Ltd.

The Nuclear Safeguards (EU Exit) Regulations 2019 (NSR19) require that operators “maintain a system of accountancy and control” and that the components of this system must be implemented “in a manner which is proportionate to and appropriate for the basic technical characteristics of the qualifying nuclear facility”.
 
SSBIs seek assurance of an operator’s compliance with NSR19, in particular the following:
  • That fit for purpose systems, structures, and components (SSCs) are in place to deliver the nuclear material accountancy, control and safeguards (NMACS) function, which are claimed within the operator’s arrangements (e.g., within the Accountancy and Control Plan (ACP)).
  • That SSCs in place for NMACS are proportionate to and appropriate for the Basic Technical Characteristics (BTC) of the qualifying nuclear facility (QNF).
  • That the implementation of SSCs is in line with the operator’s documented arrangements.
  • That SSCs meet ONR’s regulatory expectations, detailed in the ONR Guidance for Nuclear Material Accountancy, Control and Safeguards (ONMACS).

Subject(s) of inspection

  • FSE 3 Competence Management - Rating: Green
  • FSE 5 Reliability, Resilience and Sustainability - 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 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 Reg17 - Unusual occurrences - Rating: Green
  • NSR19 Reg20 - Weight units and categories of qualifying nuclear materials - Rating: Green
  • NSR19 Reg29 - Stock list and accounting records for conditioned and retained waste - Rating: Green
  • Overall Inspection Rating - Rating: Green

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

This planned compliance inspection was conducted between 31st October and 2nd November 2023. I have sampled the following facilities within the material balance area (MBA) QS14, involved in plutonium contaminated material (PCM) management:

  • Plutonium Management Facilities (PMF) North PCM Waste Handling Facility (WHF)
  • Engineered Drum Stores (EDS) 1, 2 & 3
  • Waste Treatment Complex (WTC).

The inspection was performed in line with relevant ONR guidance, which can be found on ONR’s website (onr.org.uk).

The inspection involved the planning phase and a two-and-a-half-day site visit, including plant walkdowns, discussions with relevant Sellafield Ltd personnel, review of records, and sampling of information contained within electronic databases and other documentation. Further information was also requested during the inspection and reviewed subsequently.

I judge that the SSCs sampled, namely, PCM Tracker, EDS Assay Suite, Total Neutron Portable Packet Monitor (TNPPM) and Plutonium Finishing and Storage Drum Monitor (PFSDM) are fit for purpose and are being implemented by Sellafield Ltd in a proportionate and appropriate manner, and in line with their own arrangements. I did not identify any significant shortfalls against NSR19 or fundamental safeguards expectations (FSEs) 3, 5, 6, 7 and 8 during the inspection.

Upon considering FSE7, I identified a shortfall in the recording of uranium measured in QS14 considered to be below limits of detection. The measurement neither proves or disproves the absence of uranium. I have raised a minor Regulatory Issue to seek further understanding and assurance that uranium is being appropriately recorded and tracked in QS14.

Upon considering FSE8, I identified ambiguity in the retained waste book balance in QS14. During the inspection, I have identified two potential mechanisms that may result in this ambiguity in the book balance when compared with physical reality in QS14. One due to re‑measurements of qualifying nuclear material (QNM) within QS14 and the other due to disposal of LLW PCM offsite. In both cases, I have identified that corresponding ICR lines are not being generated to balance the book inventories. I have raised a minor regulatory issue for Sellafield Ltd to investigate the extent of this ambiguity.

I also observed minor inconsistencies against FSE5, FSE7 and FSE8 and reflected these in regulatory advice provided to Sellafield Ltd.
 
Overall, based on my inspection sample, I was satisfied that Sellafield Ltd has provided adequate level of assurance and evidence to demonstrate compliance with the requirements of NSR19 and FSEs 3, 5, 6, 7 and 8.

Conclusion

Upon consideration of the ONR guidance on inspection ratings, I judge that a rating of green (no formal action) is appropriate.

I provided feedback to Sellafield Ltd on the inspection findings at the close-out meeting onsite