Office for Nuclear Regulation

Hinkley Point C – Inspection ID: 51671

Executive summary

Date(s) of inspection:

  • January 2023

Aim of inspection

The aim of the inspection was to assess the adequacy of NNB Generation Company (HPC) Ltd’s (NNB GenCo) arrangements for the manufacture of the Hinkley Point C (HPC) pressurisers at ENSA Spain, specifically those relating to Licence Condition (LC) 17 and LC19. The pressurisers are classed as high integrity components (HICs) and, as such, attract additional measures beyond those required by the RCC-M code to demonstrate very high structural reliability.

ENSA is manufacturing the HPC pressurisers under a sub-contract to Framatome, the primary contractor for the manufacture and installation of the primary circuit. It is important that NNB GenCo maintains a level of oversight and control over the manufacture of the pressurisers that is commensurate with the high integrity classification of these components.

ONR intends to apply regulatory control over the release of the first pressuriser from ENSA. This inspection provided some of the evidence to support ONR’s permissioning decision.

ONR participated in a multinational inspection (alongside the French ASN and US NRC) in October 2019; that inspection covered the general arrangements and, in particular looked at those arrangements that controlled important technical aspects such as welding and mechanical testing. The inspection reported here was a timely follow-up that focused on HPC operations and at a time when the pressurisers were at an advanced stage of manufacture. I considered that the arrangements for the technical aspects had been adequately covered during the multinational inspection and were therefore not considered during this inspection. I did, however, review the recovery plan to address the shortfalls in ultrasonic inspection identified in 2020.

Subject(s) of inspection

  • LC 17 – Management systems – rating: Green
  • LC 19 – Construction or installation of new plant – rating: Green

Key findings, inspector’s opinions and reasons for judgement made

The inspection was performed at ENSA’s heavy manufacturing facilities at Santander, Spain over two day period and considered a range activities summarised below.

The inspections reviewed ENSA’s programme for developing an appropriate safety culture for the manufacture of safety significant nuclear components. While ENSA has several tools and initiatives for addressing human performance and promoting nuclear safety culture, its self assessment recognised that further improvements were required. As an example of the improvements it was noted that recent developments included the use of checklists to reinforce the pre-job briefs.

ENSA and Framatome’s processes for managing non-conformances were reviewed and from the several examples that were used as evidence, the inspection concluded that the non-conformances were managed appropriately and that NNB GenCo and the surveillance bodies had adequate visibility.

ENSA’s management system includes dedicated procedures for mitigating the risk of counterfeit, fraudulent and suspect items (CFSI) entering its supply chain and training is provided to its staff and supplier. ENSA includes specific CFSI requirements in its supplier purchase orders. Within the time available, the inspection was unable to go any deeper into ENSA’s prevention of CFSI.

Since one of ENSA’s major manufacturing activities is welding, the inspection examined the control and issue of welding consumables. A visit was made to the welding consumable store enabling a review to be made of the processes for the storage, treatment and issue of welding consumables. The digital workflow process managed through workstations in the workshop was considered as effective in ensuring that only qualified welders were issued with welding consumables by the store’s supervisor.

ENSA suspended ultrasonic testing in 2020 due to shortfalls identified in reporting. ENSA had developed a recovery plan which included additional training of operators and improved non-destructive testing (NDT) procedures. As a result of a follow-up audit by Framatome and a review of the findings by NNB GenCo, ENSA was instructed to resume ultrasonic testing. The inspection concluded that ENSA’s recovery plan was comprehensive and complete and that the decision to resume NDT operations was appropriate.

In addition to a review of ENSA’s activities, the inspection looked at NNB GenCo’s surveillance arrangements implemented through EDF Direction Industrielle (DI). DI reported that it had not missed any of the planned surveillance activities and that additional surveillance had been undertaken in response to specific findings such as the resumption of NDT activities by ENSA. The inspection noted that DI had produced important inspection information that would not be made available to NNB GenCo. For example, DI had performed its own ultrasonic NDT to confirm the results obtained by ENSA and while the result of the inspection is expected to be included in the manufacturing records, the full inspection report would not. ONR considered that this was a generic issue and would discuss the matter with the NNB GenCo Quality Director.

It was noted, that NNB GenCo’s surveillance plan had recently been revised to include, amongst other things, a refreshed programme of joint inspections between NNB GenCo and DI.


The inspection gathered evidence over a range of areas and the overall conclusion was that the arrangements are effective for controlling the manufacture of the HPC pressurisers. While there appeared to be some weaknesses in safety culture, it was considered that the ENSA quality arrangements, along with the oversight provided through the tier 1 contractor and the surveillance activities, are sufficient to assure the quality of the HPC items.

The inspection concluded that NDT shortfalls identified in 2020 have been adequately addressed that allowed ENSA to resume its NDT activities.

The shortfalls that were identified during the inspection will be followed up through normal regulatory business, but as these shortfalls were considered as relatively minor, or of a generic nature, the inspection was rated as GREEN.