Executive summary
Date(s) of inspection:
- October 2024
Aim of inspection
The aim of this inspection was for ONR to gain assurances that the licensee’s arrangements for commissioning LVL System (400V AC Uninterrupted Power Supply Distribution) are adequate and that those arrangements are being implemented on site in a suitable, sufficient and safe manner. ONR was also seeking to gain confidence on the licensee's governance arrangements.
Subject(s) of inspection
- LC 21 - Commissioning - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The evidence sampled provided confidence that the implementation of arrangements for commission LVL System Phase 1 were adequately controlled.
I gained confidence on safety arrangements during commissioning, due to the demonstration of adequate control of the isolation of Electrical Supplies to the LVL Electrical Board following a Lock Out Tag Out (LOTO) process.
I gained assurance that there are sufficient SQEP commissioning staff for this stage of commissioning, due to the evidence witnessed on training governance, including controls ensuring personnel are SQEP during setting to work, and interaction with the Electrical Commission Team.
This inspection highlighted a large number of manufacturing related defects on the LVL board, whilst not significant at this time these will be subject to oversight at future inspections on LVL Phase 2 & 3 due to a common site-wide Low Voltage board manufacturer, including nuclear safety rated boards.
On the basis of the evidence sampled, and in recognition of progress to date, I was satisfied that the arrangements in place comply with LC 21.
Conclusion
On the basis of the evidence sampled, I judge that NNB GenCo has adequate arrangements under LC21 (Commissioning) for the NNB GenCo led LVL Phase 1 commissioning and that it was being performed in a safe manner, with adequate demonstration to compliance of surveillance, open point, commissioning and safety rules processes.
Upon consideration of the ONR guidance in relation to inspection ratings, I judge that a rating of Green (no formal action) is appropriate.