Executive summary
Date(s) of inspection: April 2024
Aim of inspection
Hinkley Point B informed ONR of their intention to notify the Competent Authority (ONR & EA) that their holdings of dangerous substances will decrease below the COMAH lower tier threshold.
The aims of this inspection are:
- to verify the removal of bulk substances, such as hydrazine, and consider the condition and status of residual plant and equipment.
- to provide reassurance on the approach taken to removing dangerous substances e.g. purging and clean down of pipework.
- to provide a judgement on the control of any residual risk, e.g. storage of remaining bulk chemicals, DSEAR arrangements, emergency arrangements
- to provide a judgement on arrangements for handover to NRS, including management of ageing plant, management of change and organisational capability.
This inspection is being conducted jointly by ONR and EA.
Subject(s) of inspection
- COMAH - Control of Major Accident Hazards Regulations 2015 - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
I conducted a COMAH exit inspection at Hinkley Point B power station (HPB). The inspection sought to examine the dutyholder’s arrangements for moving from a lower tier COMAH site to a sub-COMAH site. Therefore, removing the legal requirement to follow the requirements of the Control of Major Accident Hazards Regulations 2015 (COMAH). The inspection was completed by the COMAH competent authority (CA). The collaborative approach was taking between the Office for Nuclear Regulation (ONR) and the Environment Agency (EA).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:
- Timeline and plans for isolation and removal of key plant.
- Management of change documentation
- DSEAR changes
- EIADR consent log changes
- Changes to the emergency handbook
- Changes to the major accident prevention policy
- Changes to the Environmental Aspects register
The site intervention centred on the removal or reduction of key dangerous substances that are either named substances or have the appropriate classification and labelling to be considered ‘COMAH substances’.The areas of site sampled were:
- Hydrazine and Ammonia tanks
- Vapourising Auxiliary Boilers (VAB) fuel tank storage compound
- Gas turbine fuel oil (GTFO) / Auxiliary Boiler Fuel Oil (ABFO) tank storage compound.
- Main Stores Diesel storage tanks & stores compound
- Charge Machine Emergency Cooling (CMEC) fuel storage tank
- Emergency Control Room changes
Regulatory judgment was based on determining compliance with COMAH 2015 including the associated guidance L111.
Conclusion
Based on the pre-inspection information and the site intervention, I judged that arrangements for removal and reduction of dangerous substances, pursuant of the COMAH regulations was adequate. The dutyholder has formally submitted its denotification from COMAH and as such is no longer considered to be a COMAH establishment.
The dutyholder was able to provide sufficient evidence of actions and arrangements that have already been completed and those that were planned for the future in further reduction, albeit under the Control of Substances Hazardous to Health Regulations 2002.
Several observations were noted verbally on the day and are captured below under Observations / Advice.
The remaining activities and outstanding actions in relation to the removal of dangerous substances will be pursued as part of routine business via a Level 4 regulatory issue, RI-12068.
Based on my sample, an inspection rating of GREEN (no formal action) has been assigned to the inspection.