Office for Nuclear Regulation

Control of Major Accident Hazards Inspection

Executive summary

Purpose of Intervention

The purpose of this intervention was to provide regulatory confidence in the management of conventional health and safety hazards present at EDF Energy Nuclear Generation Limited (NGL) Hinkley Point B power station (HPB).  Specifically, in relation to the Control of Major Accident Hazards Regulations 2015 (COMAH).  The inspection is part of the annual COMAH intervention programme agreed with the facility.

The visit was organised and led by the Environment Agency (EA) as part of the Competent Authority (CA), to assess adequacy of the COMAH management system, inspect tank storage and containment arrangements including maintenance management and to close out actions from previous inspections.  The intervention provided a site familiarisation opportunity for the new ONR COMAH Inspector, alongside information gathering to enable strategic targeting of future interventions.

Interventions Carried Out by ONR

A site inspection was conducted on 24 February 2021, followed by a remote intervention on 9 March 2021.  Consistent with internal ONR and EA Coronavirus (COVID-19) arrangements, the two-part intervention structure was introduced to reduce personal contact time.

The key regulatory activities undertaken during the two-day inspection to provide regulatory confidence in the application of COMAH are summarised below:

Explanation of Judgement if Safety System Not Judged to be Adequate


Key Findings, Inspector's Opinions and Reasons for Judgements Made

I reviewed the COMAH management system based upon the HPB Major Accident Prevention Policy (MAPP) and I observed detailed arrangements linked directly to achieving COMAH compliance. I judged that HPB demonstrated an understanding of COMAH regulations and the actions necessary to achieve compliance. I was reassured the inventory of COMAH substances was being monitored and managed in line with internal technical specifications and COMAH threshold boundaries. In preparation for the end of power generation there is a need for HPB to clearly define dangerous substance requirements.

To ensure consistent emergency arrangements, the CA recommended the inclusion of a clear link between the MAPP and the Site Emergency Handbook, furthermore, future emergency exercises should encompass response to large a chemical spill.

In the areas sampled, I observed good standards of tank storage and secondary containment. I determined that COMAH bulk storage vessels and associated assets are being adequately managed and maintained. I noted that when issues are identified by HPB, such as engineering defects or corrosion, corrective action is planned, scheduled and implemented.

The CA discussed tanker off-loading and I noted that this activity is being actively monitored by HPB.  I encouraged HPB to continue ongoing efforts to ensure that tanker off-loading is consistently conducted in compliance with site instructions.

The HPB *DSEAR risk assessment is applicable across the site, however the potential exclusion of the VAB fuel storage tanks may be a shortfall.  This matter will be followed up by ONR and resolved with the dutyholder.

My site intervention did not involve specific focus on Covid 19 arrangements. However, throughout the visit I observed consistent compliance with hand sanitising, social distancing rules and the wearing of surgical type face coverings.

*Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR)

Conclusion of Intervention

Good standards were observed during the intervention in relation to the dangerous substance bulk storage locations inspected. The completion of corrective actions identified during previous interventions was confirmed. The COMAH management system arrangements sampled, including dangerous substance inventory controls were judged to meet COMAH regulatory requirements. In addition, COMAH notification requirements were clarified by the CA in relation to the end of power generation.

A potential shortfall regarding DSEAR was identified and this matter will be followed up by ONR as part of the CA and addressed with HPB through normal business interaction.

An inspection rating of Green has been applied to this intervention.