- Site: Hartlepool
- IR number: 22-041
- Date: July 2022
- LC numbers: 23
Purpose of Intervention
This intervention was a planned inspection of LC23 (Operating Rules) at EDF Energy Nuclear Generation Limited’s (NGL) Hartlepool Power Station. Its purpose was for ONR to judge the adequacy of EDF NGL’s compliance with its LC23 arrangements, with a specific focus on the arrangements for in-reactor detection and management of failed fuel.
The intervention stemmed from a recommendation made in ONR’s assessment of EDF NGL’s safety case for in-reactor detection and management of AGR fuel failures occurring during normal operation. The recommendation stated that “After allowing sufficient time for the new arrangements to be implemented, ONR should sample compliance with the arrangements as part of a suitable LC23 regulatory intervention.”
In early 2022 two suspected fuel failures were identified at Hartlepool Power Station in reactors 1 and 2. Although it was ultimately concluded by EDF NGL that failed fuel was not in fact present in either core, these incidents nevertheless required EDF NGL to implement its LC23 arrangements associated with failed fuel management. In sampling EDF NGL’s compliance with its arrangements, I therefore focused on its response to these two incidents.
Interventions Carried Out by ONR
I carried out this intervention over a single day in my capacity as an ONR Fuel & Core specialist inspector. I was supported remotely for part of the inspection by ONR’s Operating Reactors Fault Analysis lead inspector. My inspection was informed by the ONR Technical Inspection Guide for LC23, NS-INSP-GD-023. This was a single day compliance inspection.
Key Findings, Inspector’s Opinions and Reasons for Judgements Made
I sampled EDF NGL’s implementation of, and compliance with, technical specifications for coolant gas activity monitoring and control of failed fuel. I targeted these because they are the operating rules most directly relevant to detection and management of failed fuel, and the operating documents with most safety significance in the scope of this inspection. I also sampled the operating instruction for operators in the control room that claims to ensure compliance with these operating rules.
I observed that these operating rules and instruction are clear, meaningful and verifiable for operators. They are adequately linked back to the underlying safety concerns and safety case via specific ‘commentary’ documents. I spoke to staff in the control room and was satisfied that they understood both the operating rules and instruction, and were able to adequately implement them.
I observed adequate records of compliance with the operating rules from both the control room and Hartlepool Nuclear Safety Group (NSG), both in the period leading up to the identification of the suspected failed fuel in Reactor 2 in January 2022 and in the week leading up to the inspection. I also observed satisfactory evidence that the NSG engineer who was involved in this process and authored technical advice to the operations team was suitably qualified and experienced.
The operating rules require operators to seek specialist advice from NSG, for example to set the strategy to locate the suspected failed fuel and ultimately exit the associated action condition. The importance of conservative decision-making when providing such specialist advice was the main driver behind the recommendation that this intervention be conducted (paragraph 2). I therefore judged it proportionate to sample EDF NGL’s compliance with operating instructions provided to NSG and Technical Client Organisation (TCO) staff to aid in providing this specialist advice. I also sought confidence that such decision-making was conservative.
I was satisfied during the inspection that the decisions and actions taken to manage failed fuel at Hartlepool in early 2022 were conservative in nature. I also saw evidence that the decisions were reached in a way consistent with guidance in the applicable instructions to NSG and TCO, with input from a cross-functional team. I judged the decisions taken to be consistent with standards contained in the EDF technical policy for operation of nuclear fuel.
Overall, informed by guidance in NS-INSP-GD-023, I judge that EDF NGL adequately implemented and complied with its operating rules for in-reactor detection and management of failed fuel at Hartlepool Power Station in early 2022.
Conclusion of Intervention
My inspection found that EDF NGL were complying with the LC23 arrangements at Hartlepool Power Station in the areas I inspected. As a result, I have rated this inspection Green. (No formal action).
I recommend that the recommendation made in ONR’s assessment of EDF NGL’s safety case for in-reactor detection and management of AGR fuel failures occurring during normal operation, to sample compliance with the arrangements as part of a suitable LC23 regulatory intervention, should now be closed.