Executive summary
Date(s) of inspection: November 2024
Aim of inspection
The Control of Major Accident Hazards (COMAH) Competent Authority are conducting a series of planned inspections across the EDF Nuclear Operations (NucOps) reactor fleet in 2023-24 & 2024-25 to verify COMAH compliance. This inspection, jointly with ONR Control & Instrumentation (C&I) specialism, forms part of this plan.
Two of ONR’s five purposes relevant to this inspection namely nuclear safety and nuclear site health and safety. The objective of this cross-purpose inspection is to gain confidence in the adequacy of EDF NucOps arrangements to ensure safety critical electrical control systems and devices are adequately identified, maintained and effective for the prevention and mitigation of major accident hazards.
This inspection will sample the production and implementation of arrangements to ensure adequate management of electrical control systems and equipment required for safety both nuclear safety and site health and safety. The arrangements on site for avoiding, minimising and preventing fire and explosion risk arising from dangerous substances will also be sampled. As part of this, it is anticipated ONR will seek to sample records (or documents) made in connection with these arrangements focusing specifically on those referenced in the Hartlepool Power Station process hazard review (PHR) report for COMAH related operations.
Arrangements to ensure compliance with Control of Major Accident Hazards Regulations 2015 (COMAH) will be sampled. A rating will be made against COMAH.
The License Conditions (LC) targeted during the inspection will be LC 27 (Safety mechanisms, devices, and circuits) and 28 (Examination, inspection, maintenance, and testing). Aspects of LC 10 (Training), LC 23 (Operating rules), LC 24 (Operating instructions) may also be sampled but are not rated.
Subject(s) of inspection
- COMAH - Control of Major Accident Hazards Regulations 2015 - Rating: Amber
- Health & Safety at Work Act - Rating: Cancelled
- LC27 - Safety mechanisms, devices and circuits - Rating: Not rated
- LC28 - Examination, inspection, maintenance and testing - Rating: Not rated
Key findings, inspector's opinions and reasons for judgement made
The Control of Major Accident Hazards Regulations 2015 (COMAH) require operators at Lower Tier COMAH sites to develop a Major Accident Prevention Policy (MAPP), which must be implemented through a safety management system (SMS). This system addresses hazard identification, evaluation of major hazards, and prevention strategies.
The inspection revealed that while the site had the required documents and arrangements in place, there were some shortfalls in compliance with safety management processes, particularly regarding the timely review of Process Hazard Reviews (PHR) and Environmental Risk Assessments (ERA). Some PHRs had not been updated to reflect changes in chemical inventories and plant modifications leading to gaps in the risk assessments.
The hydrazine dosing plant upgrade project, which reduced risk by switching to a less hazardous hydrazine product, was implemented without adequate reference to the process defined in EDF Nuclear Operations engineering change process. There were inadequacies with the classification of safety critical equipment (SCE), such as the failure to categorise certain tank instrumentation as COMAH SCE, which resulted in insufficient maintenance and testing. The engineering change also failed to assess the implications of installation of new equipment on the bund capacity requirements for prevention of major accident to the environment (MATTE).
Conclusion
Based on the sample inspection I judge the deficiencies identified in the identification and management of major accident hazards for the hydrazine on site were significant. The engineering change undertaken in 2018-19 did not consider COMAH implications, and resulted in COMAH SCE not being inspected. This is a shortfall of Regulation 7(8) of COMAH 2015, Schedule 2 which specifies the requirements of an effective safety management system. I have therefore assigned an amber rating with respect to COMAH compliance.
To bring about improvement in future compliance, I have raised one Level 3 regulatory issue (RI-12336).
Due to the need during the intervention to focus on the shortfalls identified under COMAH, it was not appropriate to rate License Conditions (LC) 27 (Safety mechanisms, devices, and circuits) and 28 (Examination, inspection, maintenance, and testing). While no evidence of specific shortfalls was identified, insufficient sampling of the arrangements was achieved to inform a rating.