Executive summary
Date(s) of inspection:
March 2026
Aim of inspection
The aim of this inspection was to examine the licensee’s implementation of arrangements for maintaining the qualification of structures, systems and components (SSCs) against seismic hazard and identifying potential interaction hazards. These arrangements included:
- LC28 – Examination, inspection, maintenance and testing of relevant SSCs.
- LC10 – Training of relevant system engineers in relation to seismic requirements and qualification of systems under their responsibility.
Subject(s) of inspection
- LC10 - Training - Rating: GREEN
- LC28 - Examination, inspection, maintenance and testing - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The inspection sampled the following three systems that have been designed or qualified to withstand seismic.:
- Decay Heat (DH) System
- Emergency Diesel Generator (EDG) System
- Secondary Shutdown (SSD) System
The inspection, where possible, followed systems from end-to-end to understand how they are seismically qualified and maintained. This enabled observations regarding plant modifications, degradation mechanisms and potential interaction hazards that may challenge the systems’ seismic withstand. We also considered whether the responsible system owners are suitably qualified and experienced persons (SQEPs) and have been provided with adequate training from a seismic perspective by the licensee.
The inspection sampled three systems that have been designed or qualified to withstand seismic. Based on our sample, the station generally appears robust to seismic hazards and no significant defects or concerns were identified that would challenge seismic qualification. The Heysham 2 design considered seismic hazard and has been supplemented, where appropriate, with seismic walkdowns of important safety systems and additional analyses, which has resulted in plant improvements. Some improvements were observed and sampled during the inspection.
Regulatory advice was provided to the licensee regarding interaction hazards introduced by temporary structures and housekeeping in seismically qualified areas. These matters were judged to be of low safety significance.
In a previous inspection for HYA (IR-54196), It was determined that there was no requirement for mandatory seismic training for system engineers. Similarly, HYB has no requirement for mandatory seismic training for system engineers, therefore, the existing regulatory issue RI-12966 raised for HYA is modified as a fleet-wide regulatory issue to consider whether extant arrangements are adequate given the licensee's ambitions to extend the lifetime of various AGR stations and availability of supporting seismically qualified system engineering staff.
Conclusion
Originally, Heysham 2 had been subject to an element of seismic design. Later on, the design has been supplemented, where appropriate, with seismic walkdowns of systems important to safety and additional analyses, which has resulted in plant improvements. Based on our sample, the station generally appears to be robust against seismic hazards, seismic controls were generally implemented and no significant defects or concerns were identified that would challenge seismic qualification.
Based on our sampling, an overall inspection rating of Green (No Formal Action) was awarded. This rating was awarded because the licensee was able to demonstrate adequate examination, inspection, maintenance and testing of systems’ seismic withstand. Appropriate use of seismically certified engineers has informed plant enhancements for seismic withstand.
The existing regulatory issue (RI-12966) in relation to mandatory seismic training of system engineers raised for HYA is modified as a fleet-wide regulatory issue to consider whether extant arrangements are adequate given the licensee's ambitions to extend the lifetime of various AGR stations and availability of supporting seismically qualified system engineering staff.