- Site: Heysham 1
- IR number: 21-022
- Date: May 2021
- LC numbers: 10, 23, 24, 27, 28
Executive summary
Purpose of Intervention
In accordance with the Office for Nuclear Regulation (ONR) Strategy, each year ONR performs a series of planned System Based Inspections (SBIs). In line with the Integrated Intervention Strategy (IIS) for 2021/22, a planned SBI on the Emergency Boiler Feed system (SBI-03) at EDF Energy Nuclear Generation Limited’s (NGL’s) Heysham 1 (HYA) power station was conducted on 18 and 19 May 2021. The purpose of this inspection was for ONR to determine the adequacy of implementation of the safety case claims in respect of the Emergency Boiler Feed system.
Interventions Carried Out by ONR
In order to determine the adequacy of implementation of the Licensee’s safety case claims in respect of the Emergency Boiler Feed system, ONR examined evidence to determine compliance against five key Licence Conditions (LCs), which are applicable provisions of the Energy Act 2013. These LCs (listed below) have been selected in view of their importance to nuclear safety and in providing a structured approach to determining whether the safety case has been implemented adequately through the system being inspected.
ONR assessed compliance against the following LCs using applicable inspection guidance:
- LC 10 Training – requires NGL to make and implement adequate arrangements for suitable training of those who have responsibility for any operations that may affect safety.
- LC 23 Operating Rules – requires NGL to produce adequate safety cases to demonstrate the safety of operations on the site, and to identify and implement operating conditions and limits necessary in the interests of safety.
- LC 24 Operating Instructions – requires NGL to make and implement adequate arrangements for the provision of suitable written instructions for undertaking any operation that may affect safety.
- LC 27 Safety Mechanisms, Devices and Circuits – requires NGL to ensure that, before a system is operated, inspected, maintained or tested, all safety mechanisms, devices and circuits are properly connected and in good working order.
- LC 28 Examination, Inspection, Maintenance and Testing (EIMT) – requires NGL to make and implement adequate arrangements for the regular and systematic EIMT of all plant which may affect safety.
The inspection was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.
The inspection sampled and examined the applicable safety case claims, through a combination of document reviews, discussions with plant operators and plant inspections to determine compliance against the selected LCs.
Key Findings, Inspector's Opinions and Reasons for Judgements Made
From the areas targeted and the evidence examined during the SBI, ONR considers that NGL has adequately implemented those safety case claims that relate to the Emergency Boiler Feed system.
Licence Condition 10 (Training) – the training records for four personnel that fulfil roles associated with the maintenance of the Emergency Boiler Feed system were sampled. All of the individuals sampled had completed the required training for the tasks identified through the maintenance work order cards, I therefore assigned a rating of Green (no formal action) for LC10.
Licence Condition 23 (Operating Rules) and Licence Condition 24 (Operating Instructions) – NGL provided adequate evidence demonstrating compliance against the Technical Specifications and associated Operating Instructions sampled during the inspection. I therefore assigned a rating of Green (no formal action) for LC23 and LC24.
Licence Condition 27 (Safety Mechanisms, Devices and Circuits, SMDCs) – I sampled shift check sheets, and was satisfied that confirmatory checks were conducted on the plant status of the structures, systems and components (SSCs) identified in the Technical Specifications relevant to the Emergency Boiler Feed system. In addition, I also sampled a number of applicable SSCs during the plant walkdown and gained confidence that they were generally in good working order. I therefore assigned a rating of Green (no formal action) for LC27.
Licence Condition 28 (Examination, Inspection, Maintenance and Testing) – I identified an ongoing theme regarding the satisfactory completion of maintenance work order cards (WOCs). I accepted that recent NGL training, delivered to improve WOCs completion standards, will require some time to fully deliver improvements. ONR have however, proposed a review of the WOC completion standards before the next statutory outage. On the basis of the breadth of sampled documentation, including the Maintenance Schedule and Work Order Cards relating to the examination, inspection, maintenance and testing of the Emergency Boiler Feed system related SSCs, I judged that HYA has adequate arrangements in place for compliance with LC28. I therefore assigned a rating of Green (no formal action) for LC28.
During the inspection I identified that Equipment Reliability Reviews (ERR) were not being completed in accordance with NGLs own arrangements. NGL describe ERRs as important to confirming that plant systems and equipment will fulfil their Nuclear Safety and non-Nuclear Safety functions safely and reliably, and to plan appropriate actions where performance gaps are identified. NGL describe that ERRs should be completed every three years. I was satisfied however, that other, day to day, activities are conducted by the system engineers to monitor system health and reliability and nuclear safety is adequately maintained. However, in response to this ERR completion shortfall a regulatory issue has been raised in order to identify the extent of condition before determining whether further enforcement action may be proportionate.
During the inspection all the NGL staff I came into contact with showed appropriate levels of Covid-19 awareness. From the physical arrangements in place when gaining access to site and during the plant walkdown. I considered that NGL adequately implemented measures to reduce the risks associated with COVID-19 transmission.
Conclusion of Intervention
From the evidence sampled during this SBI, it was judged that there were no matters that have the potential to impact significantly on nuclear safety. Consequently, an overall rating of Green was awarded for the Emergency Boiler Feed system as a whole. The inspection findings were shared and accepted by NGL as part of normal inspection feedback. ONR considers NGL adequately demonstrated ownership and implementation of the shutdown systems safety case to ensure and maintain nuclear safety.