Heysham 1 - Inspection ID: 52049 | Office for Nuclear Regulation

Executive summary

Date(s) of inspection:

February 2023

Aim of inspection

In accordance with the Office for Nuclear Regulation’s (ONR’s) Operating Facilities Strategy, ONR undertakes planned system based inspections (SBIs) targeted at those structures and systems important to safety. This was a SBI of sea defences, flood protection and drainage at EDF Energy Nuclear Generation Limited’s (NGL) Heysham 1 (HYA) nuclear power station. Flooding hazards, if not controlled, can present risks to nuclear safety including common cause failure of safety systems. It is important that the risks from flooding are protected and mitigated against. This SBI sought to establish how HYA flooding safety cases are implemented in safety structures and systems (SSS), and safety functions requirements are delivered. EDF NGL’s arrangements made under relevant Licence Conditions (LCs) were assessed to determine the adequacy of their implementation in relation to SSS relevant to flooding hazards. This intervention was planned in accordance with ONR’s Operating Reactors sub-division Integrated Intervention Strategy (IIS) for 2022/23. The intervention enabled ONR to gather intelligence with respect to:

Lifetime Asset Management Plans (LAMPs).
Time limited flooding safety cases.
Updates to the stations arrangements for extreme weather including flooding.

Development of Lifetime Asset Management Plans (LAMPs).
Time limited flooding safety cases.
Updates to the stations arrangements for extreme weather including flooding.

Subject(s) of inspection

LC 10 - Training - Rating: GREEN
LC 23 - Operating rules - Rating: GREEN
LC 24 - Operating instructions - Rating: GREEN
LC 27 - Safety mechanisms, devices and circuits - Rating: GREEN
LC 28 - Examination, inspection, maintenance and testing - Rating: GREEN
LC 34 - Leakage and escape of radioactive material and radioactive waste - Rating: Not Rated
Overall Inspection Rating - Rating: GREEN

Key findings, inspector's opinions and reasons for judgement made

Nuclear safety risks from flooding hazards can be significant if not adequately controlled. ONR inspected the adequacy of EDF NGL’s arrangements made under relevant licence conditions and their implementation in relation to SSS that protect against flooding hazards. LC10 – I sampled training records for operators responsible for some of the inspected SSS. Based on my sample, the operators have received adequate training. The use of a competence matrix is good practice and EDF NGL should consider cascading its use to other teams. I advised that sampling of contractors’ competence would improve EDF NGL’s confidence that they meet quality requirements. Overall, I judge that EDF NGL is adequately implementing its training arrangements in relation to SSS protecting against flooding hazards. I award a Green rating. LC23 – I sampled technical specifications (Tech. Specs) for SSS relevant to flooding hazards. I received evidence confirming surveillance routines required by the Tech. Specs were completed. I advised EDF NGL that a permanent installation for turbine hall dewatering pumps should be considered, given they protect against frequent and design basis faults. The permanent installation should facilitate functional testing of the pumps. Overall, I judge that EDF NGL is adequately implementing its arrangements with respect to operating rules for SSS relevant to flooding. I award a Green rating. LC24 – I sampled several instructions for SSS relevant to flooding hazards. I found good practice in the explicit instruction for a controlled reactor shutdown, as it removes ambiguity. I judge EDF NGL is adequately implementing its arrangements for operating instructions relevant to SSS protecting against flooding hazards. I award a Green rating. LC27 – I sampled arrangements for safety devices, mechanisms and circuits (SDMCs) related to SSS, which protect against flooding hazards. This sample included instructions and maintenance routines. I saw evidence that the SDMCs were available, and routinely checked and maintained. I judge EDF NGL is adequately implementing its arrangements with respect to safety devices, mechanisms and circuits that support SSS protecting against flooding hazards. I award a Green rating. LC28 – I sampled examination, inspection, maintenance and testing (EIMT) routines for SSS protecting against flooding hazards. I received evidence to show flood barrier non-return flap valves were being adequately maintained. I observed several dam boards with degraded seals, although emergency equipment, I provided advice to EDF NGL to replace perished seals and ensure adequate maintenance is being performed. I judge that EDF NGL is adequately implementing its arrangements in relation to SSS protecting against flooding hazards. I award a Green rating. LC34 – Based on the SSS sampled, no significant sources of radioactive waste or material were identified. No rating is awarded. Overall, I found that EDF NGL’s existing arrangements made under the inspected LCs were being adequately implemented with respect to the observed SSS that protect against flooding hazards. I did not identify any significant shortfalls, and no regulatory issues have been raised. Where appropriate, I provided advice to EDF NGL. On this basis I award EDF NGL an overall Green rating.

Conclusion

I have sampled EDF NGL’s arrangements relevant to HYA SSS that are claimed to protect against flooding hazards. I have identified some minor shortfalls, and provided advice to EDF NGL, where appropriate. I have also identified some good practices, which EDF NGL could cascade across the station, and potentially to the wider EDF NGL fleet, where appropriate. Overall, I found that EDF NGL’s existing arrangements made under the inspected LCs were being adequately implemented with respect to the observed SSS that protect against flooding hazards. On this basis I award EDF NGL a Green rating.