Executive summary
Date(s) of inspection:
March 2025
Aim of inspection
This was a planned inspection of EDF Nuclear Generation Limited's (NGL's) implementation of operational arrangements for Seasonal, Severe Weather and Marine Impact Preparations (“Seasonal Readiness”) at Sizewell B Nuclear Power Station (SZB). The purpose of this activity was to ensure that risks associated with seasonal hazards are being adequately managed by the licensee. Seasonal readiness arrangements include routine and other preparations (e.g., defects and asset maintenance) intended to mitigate risks associated with predictable summer and winter conditions.
Subject(s) of inspection
- LC6 - Documents, records, authorities and certificates - Rating: Not rated
- LC24 - Operating instructions - Rating: Green
- LC28 - Examination, inspection, maintenance and testing - Rating: Green
Key findings, inspector's opinions and reasons for judgement made
The inspection comprised discussions with the Seasonal Readiness Coordinator, related Engineering and Independent Nuclear Assurance staff (INA) staff. The discussions focused on the implementation of both summer and winter preparedness activities in relation to Licence Conditions 6 (Documents, records, authorities and certificates), 24 (Operating Instructions) and 28 (Examination, Inspection, maintenance and testing) .
I sampled local documentation, work order cards and associated records on SZBs Asset Management System to gather evidence that SZB was adequately implementing its arrangements detailed in the company specification “Seasonal, Severe Weather and Marine Impact Preparations”. I undertook a plant walkdown, which enabled inspection of plant identified by the arrangements. I saw parts of the Heating Ventilation Air Condition (HVAC) that are components of the Safety Classified Electric Engineering (SCEE) system, trace heating system, chemical tanks, and the hypochlorination plant.
Conclusion
I inspected the adequacy of SZB’s implementation of EDF’s seasonal readiness arrangements against relevant licence conditions. Overall, the inspection was rated Green (No Formal Action) as no compliance gaps or significant issues were identified, based on my sample. Ratings and a summary justification for each Licence Condition were:
LC 6 –Not rated. Insufficient evidence was gathered during the inspection activity to rate against this LC.
LC 24 –Green rating (no formal action). I judged that SZB has implemented adequate seasonal readiness arrangements for both winter and summer. The operating instructions are in-line with the fleet wide requirements. A Seasonal Readiness Coordinator has been appointed within the work planning team, given appropriate access to relevant data and interaction with other groups. I provided regulatory advice where I identified potential minor improvements to the extant seasonal readiness arrangements.
LC 28 –Green rating (no formal action). I was provided with evidence that SZB are undertaking effective examination, inspection, maintenance and testing of systems related to seasonal readiness. I therefore judged SZB were adequately implementing their arrangements. I observed that the station proactively entered the “event recovery” process in February 2025, thereby ensuring that safety classified heating and ventilation equipment would be appropriately prioritised in preparation for summer 2025. I identified potential minor enhancements to the implementation of EDF’s seasonal readiness arrangements and provided Regulatory Advice.