Executive summary
Date(s) of inspection: November 2023
Aim of inspection
The aim of the inspection was to examine the adequacy of NNB Generation Company (HPC) Ltd's (NNB GenCo) implementation of its Licence Condition (LC) 19 compliance arrangements to assess:
- preparation and generation of the end of manufacturing report (EoMR) for the unit 1 steam generator 1 (#428);
- to sample various parts of the EoMR starting with the treatment of the ingots to end of manufacture following the hydrotest;
- Independent Third Party Inspection Agent (ITPIA) surveillance;
- evidence from the test data; and
- evidence demonstrating compliance with the Nuclear Pressure Equipment (NPE) policy.
I undertook the inspection in support of ONR's permissioning of the 'ex-works' for unit 1 steam generators 1 (#428) and 3 (#429). Considering the challenges a future operator might face, I sampled the EoMR with a 'cradle to grave' approach focused on the tubesheet and on material traceability between the original manufacturer Japan Steel Works and the test house in the UK, Jacobs, who undertook material testing independently. I also focused on the surveillance undertaken by the ITPIA.
Subject(s) of inspection
- LC19 - Construction or installation of new plant - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
Although the process of assimilating all the evidence in consolidating the EoMR is a substantially challenging activity, I drew confidence that the licensee's arrangements are sufficiently robust to ensure that preparation and generation of the EoMR for the unit 1 steam generator 1 (#428) was done correctly and with sufficient scrutiny to check for veracity of the final uploaded document.
Based on sampling various parts of the EoMR, I could follow the golden thread of evidence starting with the treatment of the ingots to end of manufacture following the hydrotest, which I deemed to meet my expectations.
I also witnessed evidence of the surveillance provided by the ITPIA during various manufacturing activities demonstrating compliance with the licensee's NPE policy.
I also saw the evidence from the test data related to material testing and chemical analysis for example, which gave me the confidence on the quality of the manufactured steam generator.
Conclusion
Overall, I was content that the EoMR for HPC unit 1 steam generator 1 (SG#428) is a comprehensive record of manufacturing and the testing results which I have sampled have provided confidence in the structural integrity of this steam generator. I consider that, in accordance with ONR guidance on the application of inspection ratings, a green rating (no formal action) against Licence Condition 19 is appropriate for this inspection.