Executive summary
Date(s) of inspection: July 2024
Aim of inspection
The aim of the inspection was to inspect NNB GenCo’s arrangements for compliance with Licence Condition 19 (LC19) – Construction or installation of new plant, in relation to civil engineering construction assurance. LC19 requires that where the licensee proposes to construct or install any new plant, which may affect safety, the licensee makes and implements adequate arrangements to control the construction or installation.
Due to the long timeframes for construction, civil engineering assets are subject to interim stages of environmental conditions, loading arrangements, temporary laydown and temporary support. There is a risk that these interim stages of construction have not been properly considered, which has the potential to introduce latent defects and foreclosure risks that could impact on nuclear safety.
The objective of the inspection was to obtain evidence in relation to the adequacy of NNB GenCo’s arrangements for the control of interim stages of construction. The particular focus of the inspection was on the implementation of arrangements to ensure compliance with the following aspects during interim stages of construction:
Conformant construction of civil engineering elements, ensuring the preservation of design intent during construction and the avoidance of latent defects that may impact upon safety case claims.
The adequacy of arrangements to control the safety of construction activities, with the aim of assessing compliance with the CDM 2015 Regulations.
The adequacy of the fire safety and emergency arrangements with the aim of assessing compliance with the Regulatory Reform (Fire Safety) Order 2005 (RRO) during construction activities.
Subject(s) of inspection
- CDM 15 - Rating: Green
- Construction Fire Safety - Rating: Green
- LC19 - Construction or installation of new plant - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
This was a combined inspection involving civil engineering, nuclear site safety and fire specialists. It involved an inspection and walk down of several work areas determined in advance of the inspection. The sample included Unit 1 Reactor Building (HR1) and Fuel Building (HK1). The day also included a series of meetings with personnel from NNB GenCo, the Principal Contractor and Bylor (a Tier 1 contractor).
The evidence sampled provided confidence that the implementation of arrangements for the management of interim stages of construction of civil engineering assets were adequately controlled. The inspection provided confidence as to conformant construction of civil engineering elements, such that design intent was preserved during construction, with the avoidance of latent defects that may impact upon safety case claims.
The inspection found that the Principal Contractor and sampled Tier 1 contractors have adequate arrangements to control the safety of construction activities, in compliance with the Construction (Design and Management) Regulations 2015 (CDM 2015). An area for improvement in the exchange of loading information between the Principal Designer and temporary works designers was recognised by NNB GenCo and will be followed up as part of routine regulatory business.
The Principal Contractor's Fire Safety Team, which continues to settle into its new structure, further demonstrated a focus on the overall management and implementation of the required fire safety standards across the site. The recent testing of the adequacy of the temporary fire doors by means of cold smoke tests is an example of the innovative approach being taken to prove the benefits of such temporary systems. A further initiative aimed at assisting the fire service in the event of a fire in the HR1 building was demonstrated. This involves the strategic placing of a series of containers used to store hose for the provision of firefighting. It contains assorted hoses, dividing breechings and branches. In addition to this, the application of temporary dry risers offers additional benefit to the fire service in providing water to otherwise difficult locations. The primary benefits are the speed with which water should be able to be at the fire scene and the reduced effort required by the fire service to get their equipment in place.
The inspection highlighted no significant regulatory issues. A number of observations were made and requests for further information were raised, which will be followed up as part of routine regulatory business.
On the basis of the evidence sampled, and in recognition of progress to date, I was satisfied that the arrangements in place comply with LC 19.
Conclusion
On the basis of the evidence sampled, I judge that NNB GenCo has adequate arrangements under LC19 (construction or installation of new plant) for the management of interim stages of construction, in relation to civil engineering elements, and that those arrangements are under implementation.
I judge that NNB GenCo has adequate arrangements to control the safety of construction activities, in compliance with the CDM 2015 Regulations. A number of observations were made, however none of the matters identified warrant formal regulatory action.
I judge that fire safety and emergency escape arrangements are adequate during construction activities. A number of observations were made, however none of the matters identified warrant formal regulatory action.
Upon consideration of the ONR guidance in relation to inspection ratings, I judge that a rating of Green (no formal action) is appropriate for each of the inspection activities.