Office for Nuclear Regulation

Sellafield – Inspection ID: 50794

Executive summary

Date(s) of inspection:

  • November 2022

Aim of inspection

The aim of this inspection was to   determine whether the safety systems, structures and components associated with the essential services (steam, electrical, air, water) in the Pile Fuel Storage Pond (PFSP) are able to adequately fulfil their safety duties (safety functional requirements), in line with claims made within the safety case.

Subject(s) of inspection

  • LC10 – Training – Rating – Green
  • LC23 – Operating rules – Rating – Green
  • LC24 – Operating instructions – Rating – Green
  • 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 – Not rated

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

ONR carried out a planned two-day system based inspection of PFSP essential services on the 22 and 23 November 2022. The inspection team comprised the Site Inspector for PFSP, Mechanical and Electrical Engineering Specialist Inspectors and a Fault Studies Inspector.  The inspection included discussions with Sellafield Ltd. personnel, review of records, documents and processes and a targeted walk down of the facility.

From the evidence sampled, I judged that Sellafield Ltd. had adequately implemented the safety case limits and conditions specified within the safety case. Furthermore, I was satisfied that the facility adequately understood the limits and conditions and their importance in the safety case. Evidence was seen that suitable and sufficient safety mechanisms, devices and circuits are properly connected and in good working order.


Overall, I found LCs 10, 23, 24, 27 and 28  to be adequately implemented in relation to the systems inspected.

Consequently, it is my opinion that for this system-based inspection a rating of GREEN – No formal action is appropriate for LCs 10, 23, 24, 27 and 28.  The essential services within PFSP are judged to be adequate.