- Inspection date(s): 28/09/2022
Purpose of inspection
This intervention was led by the Office for Nuclear Regulation (ONR) inspector responsible for civil engineering construction assurance (CECA) and sought to assess the licensee’s (NNB Generation Company HPC Limited – NNB GenCo) application of relevant good practice in relation to structural concrete installation for nuclear safety classified structures of the Hinkley Point C (HPC) nuclear island. Reinforced concrete structures, for example the unit 1 inner and outer containment, and variations in the unit 2 inner and outer containment, by exception, were within scope.
ONR aimed to gain oversight of the management of structural concrete installation from implementation of the specification, batching, placement to curing and finishing. The general aims of this intervention were to derive confidence that:
- arrangements are in place to control material conformance of structural concrete mix constituents and reinforcement installed in the permanent works;
- pre-pour structural concrete preparation and handling arrangements in implementation meet relevant good practice and conform with the design intent;
- structural concrete placement arrangements in implementation meet relevant good practice and conform with the design intent;
- post-pour structural concrete curing and finishing arrangements in implementation meet relevant good practice and conform with the design intent and the safety case; and
- site quality control and records associated with structural concrete meet relevant good practice and conform with the design intent and the safety case.
Subject(s) of Inspection
The following actives were the subject of this inspection:
- LC 19 – Construction or installation of new plant (RAG rating: Green)
Responses to questioning were forthcoming, constructive, and provided confidence that structural concrete installation, where sampled, was being adequately managed with due consideration of the risks involved.
A small number of minor observations were made.
Overall, I was satisfied with the adequacy of NNB GenCo’s ongoing structural concrete installation arrangements.
This intervention examined in some detail the licensee’s compliance with Licence Condition (LC) 19 with regards to implementation of arrangements relating to structural concrete installation.On the basis of the evidence sampled, and in recognition of progress to date, I was satisfied that the arrangements in place comply with LC19.
My overall judgement for the intervention concludes that based on the evidence sampled, I was satisfied that arrangements in place address the key risks associated with structural concrete installation. Furthermore, those arrangements are under implementation and areconsistent with relevant good practice as defined in ONR regulatory guidance. This intervention highlighted no significant issues. All matters identified will be carried forward to routine level 4 interactions. The intervention was therefore rated as green.