Executive summary
Date(s) of inspection
- May 2026
Aim of inspection
To provide a judgement on compliance with LC19 in relation to arrangements for manufacturing. The outcome will be an informed judgement on the adequacy of NNB GenCo's oversight of MSL manufacturer (Bilfinger) and will consider how safety related requirements are demonstrated through working practices in inform ONR's judgement on MSL ex-works from a structural integrity perspective.
Subject(s) of inspection
- LC19 - Construction or installation of new plant - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
The main steam line system containment penetration assembly (MSL CPA) is manufactured by Bilfinger Nuclear & Energy Transition GmbH (Bilfinger), Germany. The MSL CPA, which forms part of the secondary steam system, has been classified by the Licensee as a high integrity component (HIC) within the Hinkley Point C (HPC) safety case. Consequences of failure of HIC components cannot be tolerated and therefore onerous highest reliability claims are made on the structural integrity of the MSL CPA. Therefore, the aim of this inspection was to make an informed judgement on the adequacy of HPC's specification, control and oversight of MSL CPA welding and non-destructive testing (NDT) at Bilfinger in accordance with LC19 to seek confidence that safety case claims are adequately justified.
During my inspection, I sampled:
- How safety case requirements had been implemented in the management of manufacturing of the MSL CPA at Bilfinger’s Dortmund manufacturing facilities.
- Licensee’s oversight of manufacturing activities.
- Supplier welding and NDT arrangements and their implementation within the facility that supported safety case claims.
From my sample, the summary of the findings from my inspection are as follows:
- I am content that LC19 arrangements regarding requirements supporting high integrity claims have been specified by the Licensee and adopted and implemented in manufacturing activities by its supplier of the MSL CPA.
- Arrangements for management of non-conformance reports (NCRs) are adequate and that these are being adequately implemented.
- I am content that adequate arrangements are in place for the training of welders who will be used in the manufacturing of HPC components and that these arrangements are being adequately implemented.
- I am content that welding and NDT inspections performed during MSL CPA manufacturing have been carried in accordance with its procedures.
- I am content that Bilfinger is controlling welding consumables in accordance with the requirements of the applicable procedures, standards and design code.
I provided regulatory advice that HPC should consider the following:
- The Licensee to consider the feasibility of implementing digitisation of manufacturing records to enable contemporaneous and single source of recording-keeping, in particular relating to follow-up documentation, prior to on-site MSL fabrication where the number of welding activities will increase significantly.
- The Licensee to consider the feasibility of implementing improvement of visual inspection during welding activities in particular prior to on-site MSL fabrication where visual inspection may be more challenging.
I will monitor the implementation of advice through routine regulatory engagement as informal actions which I will consider further in particular as part ONR’s schedule readiness inspection prior to MSL on-site welding activities.
Overall, I am content that the licensee has adequate LC19 arrangements in place for welding and NDT of the MSL CPA at Bilfinger, and that these arrangements are being adequately implemented.
Conclusion
At the time of my intervention, and from the information I have sampled, I consider that, in accordance with ONR guidance on the application of inspection ratings, a GREEN rating is appropriate for this LC19 inspection.