Executive summary
Date(s) of inspection:
March 2026
Aim of inspection
To judge the adequacy of NNB's arrangements and their implementation in relation to both classified and non-classified heating, ventilation and air conditioning (HVAC) systems.
Subject(s) of inspection
- CDM 15 (Client / PD / PC duties) - Rating: GREEN
- Fire (Life Safety) Compliance Inspection - Rating: GREEN
- LC19 - Construction or installation of new plant - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
My inspection was conducted over two days and involved four inspectors from the Mechanical Engineering, Life Fire Safety and Quality / Installation Assurance specialisms. It took place at the Hinkley Point C site, operated by the nuclear site licensee NNB Generation Company (HPC) Limited (referred to as NNB). I visited the Unit 1 Safeguard Buildings and Conventional Island Electrical Building.
The inspection sampled the following areas and legal instruments:
- Installation, protection, inspection and preservation of Class 1 and/or Class 2 HVAC systems;
- Alignment between nuclear safety relevant good practice and life fire safety relevant good practice, and how conflictions are managed;
- Management of installation works with multiple contractors, and how reinstallation risks are managed;
- The approach being taken to the management and application of fire safety by the Principal Contractor and Tier 1 Contractors; and,
- How risk assessments have informed suitable and sufficient risk reduction measures being put in place in relation to fire safety.
- The Health and Safety at Work etc. Act 1974
- The Regulatory Reform (Fire Safety) Order 2005
- The Construction (Design and Management) Regulations 2015
I sampled four safety classified HVAC systems and one safety classified chilled water system that supplies chilled water to the Class 1 safety systems. During my inspection I noted several areas where improvements were necessary, in particular in relation to foreign material exclusion and general housekeeping. That said, none of the shortfalls are significant, and should be suitably addressed by implementing extant arrangements.
The revised arrangements for planning and sequencing of installation works were reported to have had a positive impact, with issues around reinstallation work becoming less frequent. There was also clear evidence that coordination between and management of contractors and works within buildings was good. Care and maintenance activities were well defined and there was clear “ownership” of these by the relevant stakeholders.
Conclusion
Following the inspection, my judgement in relation to the planned scope is:
The arrangements and activities undertaken to install, protect, monitor and preserve the classified HVAC systems were sufficient. There were though, areas noted that require NNB and the relevant contractors to address minor shortfalls. For example, foreign material exclusion, housekeeping in general and ensuring that the space around equipment was sufficient, when boxed, to allow suitable visual inspections.
NNB has arrangements in place to ensure that any conflicting requirements between nuclear fire safety and life fire safety are appropriately identified and managed. I was unable to inspect these arrangements and their implementation, however NNB committed to providing an example of such, which I will follow-up on during future Mechanical Engineering Level 4 meetings.
The management of contractors within the buildings visited was good. Time and resource were set aside each day to brief teams and ensure a thorough understanding. That said, and despite improvements that have been implemented to mitigate the risk, there are still instances where installed HVAC equipment is having to be removed to enable access for installing of other systems around them. This is a subject that ONR will inspect further during its Installation and On-site Fabrication Assurance (IOFA) Level 4 meetings. I raised questions in relation to optioneering and the ongoing certification of installed fire dampers. This relates to the design and manufacture of the dampers, but it does impact the installation works. I committed to following this up with NNB and the contractor during a future Mechanical Level 4 Meeting in June 2026.
In relation to the management, application and risk assessment of life fire safety by the Principal Contractor and Contractors, NNB and the two contractor organisations sampled demonstrated an appropriate approach to fire safety. Ahead of the inspection, the work authorisation related to fire safety for one of the intended building had been removed, due to deficiencies in the fire risk assessment, noted by NNB. This demonstrated a robust approach, and aligned with ONR's expectations for such.
NNB and the Tier 1 contractors sampled during my inspection provided sufficient evidence to demonstrate that the arrangements and their implementation was to an appropriate standard. Given this, I have rated the inspection GREEN, as relevant good practice was generally met with minor shortfalls identified when compared with appropriate benchmarks, in accordance with ONR guidance within NS-INSP-GD-064 General Inspection Guide. These minor shortfalls have been communicated to the relevant dutyholders.