- Site: Hinkley Point C
- IR number: 21-034
- Date: November 2021
- LC numbers: 12, 14, 17
Executive summary
Purpose of Intervention
The purpose of the intervention was to gain confidence in the adequacy of NNB Generation Company (HPC) Limited’s (NNB GenCo) arrangements, and those of its supporting organisations, covering the factory acceptance (validation) testing of the protection system (PS) and how this activity supports the safety case.
Interventions Carried Out by ONR
Office for Nuclear Regulation (ONR) control and instrumentation (C&I) specialist inspectors undertook an intervention with NNB GenCo (via teleconference with Framatome), on a sampling basis, to form a judgement on the adequacy of the arrangements associated with the factory acceptance testing (FAT) of the PS for Hinkley Point C (HPC).
ONR technical assessment guides NS-TAST-GD-051 (the purpose, scope, and content of safety cases), NS-TAST-GD-049 (licensee core safety and intelligent customer (IC) capabilities) and expectations for compliance with licence condition (LC) 12 (duly authorised and other suitably qualified and experienced persons), LC 14 (safety documentation) and LC 17 (management systems) were used to inform ONR’s judgement during this intervention.
Explanation of Judgement if Safety System Not Judged to be Adequate
Not applicable as this was not a system/structure-based inspection.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
Based on the evidence presented, I identified areas of good practice relating to the procedures for specifying required quality, scoping and implementation of testing, demonstrating that adequate arrangements are in place. It is judged that the processes in place allow for adequate specification, production of procedures and assessment of testing performed on the PS version 1 (V1) at reference configuration 1.2 (RC1.2).
NNB GenCo has identified to ONR the re-scoping of the original V1 testing scope; specifically, the V1 testing activities are ‘debugging’ only and no safety claims are made on the V1 testing from a PS application software perspective. However, it is determined from the intervention that issues identified from the testing will be used to inform the RC2 design. I therefore consider the V1 testing impacts the production excellence (PE) demonstration and sets expectations for procedural compliance required for a class 1 safety system.
I found areas that require improvement, relating to:
- implementation of the arrangements during testing;
- configuration control of test procedures; and
- adequate identification of tickets raised on test records for anomalies identified during testing.
Due to COVID-19 and restrictions in travel, NNB GenCo has been unable to witness the testing performed. However, I consider through regular communication, NNB GenCo has demonstrated satisfactory oversight of the FAT activities performed by Framatome to underpin its intelligent customer role.
Conclusion of Intervention
I judge that an intervention rating of GREEN (no formal action) is appropriate for LC 12 (duly authorised and other suitably qualified and experienced persons).
I judge that an intervention rating of AMBER (seek improvement) is appropriate for LC 14 (safety documentation) and LC 17 (management systems).
LC 12 – I judge the arrangements in place are adequate to ensure that only suitably qualified and experienced persons are performing duties which may impact safety (in this case the testing of the PS).
LC 17 – I judge the licensee has established quality management systems that identify adequate arrangements for performing validation testing of the PS. Although NNB GenCo has stated no safety claim will be made against PS V1 FAT performed, NNB GenCo confirmed that anomalies identified from the PS V1 testing will be taken forward and addressed at PS RC2. Therefore, based on my findings relating to inadequate implementation of the testing arrangements with the potential to impact modification of a system delivering nuclear safety functions, I consider procedural non-compliance has been demonstrated.
LC14 – NNB GenCo identified to ONR prior to the intervention the de-scoping of PS FAT V1 to one of a ‘debugging’ exercise. It is determined that the simulation-based validation tool (SIVAT) and test bay activities used to support debugging of procedures have identified anomalies in the software that are tracked by raising HPC tickets.
Although the raising of tickets appears in accordance with arrangements, I judge a lack of adherence to process and procedures at PS V1 FAT, for example, test procedures not signed, and records not completed including a lack of ticket traceability in test records, which undermines the veracity of the findings from the testing. I judge this has the potential to impact the demonstration of PE and justification of safety during the design phase of the PS.
It is acknowledged that the areas of improvement listed above (para. 7) are broadly consistent with NNB GenCo’s own lessons learned review of PS RC1.2. Therefore, I have raised the following level 4, rather than level 3, regulatory issue (RI): RI 10454 “Protection System V1 factory acceptance testing findings” to ensure these improvements and commitments are implemented ahead of PS V2 FAT.