Executive summary
Date(s) of inspection:
March 2025
Aim of inspection
The purpose of this inspection is to sample the adequacy of Sellafield Ltd's arrangements across COMAH establishments for the management of COMAH critical pipework, rotating equipment and pumps. This inspection if supported by ONR Mechanical Engineering team as well as the Environment Agency as part of the COMAH competent authority.
Subject(s) of inspection
- COMAH - Control of Major Accident Hazards Regulations 2015 - Rating: GREEN
- LC 28 - Examination, inspection, maintenance and testing - Rating: GREEN
- Provision and Use of Work Equipment Regulations 1998 (PUWER) - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
I conducted a COMAH inspection at Sellafield Ltd. The inspection sought to examine the dutyholder’s arrangements for managing safety critical pipework and rotating equipment associated with the storage of dangerous substances, as required by the Control of Major Accident Hazards Regulations 2015 (COMAH). The inspection was completed by the COMAH competent authority (ONR/EA) and an ONR Mechanical Specialist Inspector.
Remote engagements were carried out in advance in preparation for the site visit to take the opportunity to sample any key documents in advance of the site intervention, areas sampled included:
- COMAH critical plant identification and substantiation
- COMAH critical plant maintenance strategy
- COMAH maintenance resource sufficiency
- COMAH mechanical integrity policy (integration with nuclear plant)
- Monitoring audit & review of the effectiveness of current maintenance strategy
- COMAH aging plant and POCO discussion (include B484 buried pipework)
This was followed up a site-based intervention centered on the pipework, supporting storage and the pumps associated with the storage of dangerous chemicals.
Pipework inspection
- Review of evidence of nitric acid pipework inspection programme, this will include the ITF nitric acid distribution pipework to THORP (given Magnox reprocessing has ceased).
- Review of evidence of COMAH critical pipework of the odourless kerosene distribution system (given sodium nitrite has been removed from site).
- Review of recent loss of nitric acid containment events from COMAH critical pipework, critical pumps or storage vessels and Sellafield Ltd’s actions to prevent re-occurrences.
- Review of evidence of nitric acid pipework inspection programme, this will include the ITF nitric acid distribution pipework to THORP (given Magnox reprocessing has ceased).
- Review of evidence of COMAH critical pipework of the odourless kerosene distribution system (given sodium nitrite has been removed from site).
- Review of recent loss of nitric acid containment events from COMAH critical pipework, critical pumps or storage vessels and Sellafield Ltd.’s actions to prevent re-occurrences.
COMAH Critical Pipework
- Review of evidence of temporary pipework repairs on COMAH critical pipework
- Review of evidence relating to the arrangements for condition monitoring of safety critical rotating equipment.
- Review of evidence of maintenance of atmospheric tanks holding COMAH inventory.
- Review of evidence of temporary pipework repairs on COMAH critical pipework
- Review of evidence relating to the arrangements for condition monitoring of safety critical rotating equipment.
- Review of evidence of maintenance of atmospheric tanks holding COMAH inventory
Site Walkdown
- Walkdown of pipework and infrastructure nitric system including the storage tanks and pipework in the ITF
- Regulatory judgment was based on determining compliance with COMAH 2015 including the associated guidance L111.
Conclusion
Based on the remote engagement, sampling of the maintenance, repairs and plant walk-down I judge that for COMAH this inspection is rated GREEN.