Executive summary
Date(s) of inspection
- October 2026
Aim of inspection
The aim of this planned system-based inspection was to assess whether the safety case requirements for the Flask Movement System at the Fuel Handling Plant had been adequately implemented in practice. The inspection considered whether the people, instructions, safety mechanisms, equipment and maintenance arrangements supporting the receipt and preparation of AGR flasks, fuel-laden lifting operations and transfer to the Transit Flask Maintenance Facility worked together to ensure that relevant structures, systems and components fulfilled their safety functions.
Subject(s) of inspection
- LC10 - Training - Rating: Green
- LC23 - Operating rules - Rating: Green
- LC24 - Operating instructions - Rating: Not rated
- LC27 - Safety mechanisms, devices and circuits - Rating: Green
- LC28 - Examination, inspection, maintenance and testing - Rating: Green
- LC34 - Leakage and escape of radioactive material and radioactive waste - Rating: Not rated
Key findings, inspector's opinions and reasons for judgement made
I, the ONR Site Inspector for Spent Fuel Services, supported by ONR Specialist Inspectors for Fault Studies, Control and Instrumentation, and Mechanical Engineering, carried out a planned system-based inspection of the Flask Movement System at Sellafield Limited’s Fuel Handling Plant.
System-based inspections enable ONR to examine whether the people, procedures, equipment and maintenance arrangements supporting a safety system work together to deliver the requirements of the safety case. This inspection sampled:
- receipt and preparation of Advanced Gas-cooled Reactor flasks;
- fuel-laden lifting operations; and
- transfer of flasks to the Transit Flask Maintenance Facility.
We considered compliance with:
- Licence Condition 10 – Training
- Licence Condition 23 – Operating Rules
- Licence Condition 24 – Operating Instructions
- Licence Condition 27 – Safety Mechanisms, Devices and Circuits
- Licence Condition 28 – Examination, Inspection, Maintenance and Testing
- Licence Condition 34 – Leakage and Escape of Radioactive Material and Radioactive Waste
We found that the safety case requirements sampled were generally being implemented adequately. We identified a clear link from the fault analysis, through the clearance certificate, to the operating instructions and quality plan used by plant personnel. The personnel sampled understood their roles and the importance of the relevant safety limits and conditions.
The safety mechanisms and maintenance arrangements sampled were clearly identified and in good working order. Maintenance documentation generally contained clear limits, conditions and acceptance criteria. We also identified evidence that equipment faults had been fed back into preventive maintenance instructions and that maintenance backlogs and corrective programmes of work were being managed through established arrangements.
We identified no new matters requiring formal regulatory action. Based on the evidence sampled, I judged compliance with Licence Conditions 10, 23, 27 and 28 to be GREEN – no formal action.
I did not assign an inspection rating for Licence Condition 24 because the categorisation and use of operating instructions at the Fuel Handling Plant remain subject to Regulatory Issue RI-13174 and planned regulatory engagement. The evidence obtained during this inspection was relevant to Action 1 of RI-13174 but did not identify a new Licence Condition 24 matter requiring separate regulatory action.
I did not assign an inspection rating for Licence Condition 34 because containment arrangements were not represented within our primary inspection samples. The information obtained will inform future regulatory inspection activity.
Conclusion
Based on the evidence sampled, I concluded that the safety case requirements for the Flask Movement System were generally being implemented adequately. I was satisfied that the personnel, instructions, safety mechanisms and maintenance arrangements sampled supported delivery of the required safety functions.
We identified no new matters requiring formal regulatory action. I therefore judged compliance with Licence Conditions 10, 23, 27 and 28 to be GREEN – no formal action.
I did not assign a rating for Licence Condition 24 because of findings from a previous inspection, the associated regulatory issue and planned further engagement. I did not rate Licence Condition 34 because containment arrangements were not included within our primary inspection samples.