Executive summary
Date(s) of inspection:
February 2026
Aim of inspection
The key purpose of the themed inspections is to gain regulatory confidence that Legacy Silos can implement credible plans to deliver timely high hazard risk reduction.
Subject(s) of inspection
- LC 10 - Training - Rating: GREEN
- LC 12 - Duly authorised and other suitably qualified and experienced persons - Rating: GREEN
- LC 24 - Operating instructions - Rating: GREEN
- LC 36 - Organisational capability - Rating: AMBER
Key findings, inspector's opinions and reasons for judgement made
The ‘People and Process’ themed inspection was completed over a 12- month period from April 2025 to March 2026. A series of inspections and observations were undertaken to gain regulatory confidence that Sellafield Ltd’s plans for full, sustained waste retrieval capability in the Magnox Swarf Storage Silos (MSSS) and Pile Fuel Cladding Silos (PFCS) are credible and supported by SQEP people and robust process arrangements.
The inspection was supported by Human Factors and Leadership and Management for Safety specialists, ensuring people, process, workload, and organisational capability were evaluated alongside operational readiness.
ONR recognised that the ongoing merger between PFCS and MSSS into a single operating unit has already created benefits and opportunities to improve the sustained long-term delivery of high hazard risk reduction (HHRR).
When compared with MSSS, long‑term planning within PFCS remains less developed and appears reactive. This constrains Sellafield Ltd’s ability to make robust decisions and to effectively challenge wider organisational priorities. Operational performance has improved and learning from early retrievals is evident. However, the future operating model was unclear and the evidence demonstrates that people and capability planning is not yet sufficiently mature, structured, or underpinned to support the safe and effective delivery of the waste retrievals programme.
These findings indicate that arrangements do not currently fully meet ONR expectations for LC36 and therefore ONR rate the inspection AMBER. ONR will raise a new Level 3 Regulatory Issue to ensure that Sellafield remediate the observed shortfall. All other LC’s considered during the inspection are rated GREEN and as such no formal action will be sought.
Conclusion
ONR recognise that the ongoing merger between PFCS and MSSS into a single operating unit has already created benefits and opportunities to improve the sustained long-term delivery of HHRR.
When compared with MSSS, long‑term planning within PFCS remains less developed and appears reactive. This constrains Sellafield Ltd’s ability to make robust decisions and to effectively challenge wider organisational priorities. Operational performance has improved and learning from early retrievals is evident. However, the future operating model was unclear and the evidence demonstrates that people and capability planning is not yet sufficiently mature, structured, or underpinned to support the safe and effective delivery of the waste retrievals programme.
These findings indicate that arrangements do not currently fully meet ONR expectations for LC36 and therefore ONR rate the inspection AMBER. ONR will raise a new Level 3 Regulatory Issue to ensure that Sellafield remediate the observed shortfall. All other LC’s considered during the inspection are rated GREEN and as such no formal action will be sought.