- Site: Hinkley Point C
- IR number: 21-027
- Date: September 2021
- LC numbers: 14
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 for the production and assessment of safety cases consisting of documentation to justify safety during the design, construction, manufacture, commissioning, operation and decommissioning phases of the installation.
Interventions Carried Out by ONR
Office for Nuclear Regulation (ONR) control and instrumentation (C&I) specialist inspectors undertook a remote intervention (via videoconference) observing the licensee’s oversight of the responsible designer (RD) performing an audit of a class 1 smart device PE assessment.
This observation was used to form a judgement on the adequacy of the arrangements associated with the qualification of class 1 smart devices, specifically the demonstration of adequate PE. The Emphasis assessment tool developed by the control and instrumentation nuclear industry forum (CINIF) was used to provide this demonstration.
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 LC 14 (Safety documentation) 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, areas of good practice relate to:
- discussions witnessed at the audit were open, transparent with a good level of challenge;
- gaps in the demonstration of PE determined from the audit of the Emphasis assessment are to be grouped into common topics / themes to enable scoping of compensating measures (CMs); and
- NNB GenCo demonstrating satisfactory oversight of the RD smart device qualification activities, and that of the supply chain, to underpin its intelligent customer role.
Based on my observations of the audit of the Emphasis assessment I found no significant areas for improvement. I will pursue the adequacy of CMs, which the manufacturer will utilise to address the gaps in PE, through regular Level 4 meetings with the licensee.
Conclusion of Intervention
I judge that an intervention rating of GREEN (no formal action) is appropriate for LC 14 (Safety documentation). I consider that the discussions were open, transparent with a good level of challenge from both the RD and NNB GenCo. This provides confidence that where smart device PE evidence was presented, the evidence is adequately robust underpinning the safety case.
I consider NNB GenCo provided adequate oversight of the process in delivery of its role of intelligent customer.