Office for Nuclear Regulation

Heysham 1 -  SBI28 - Shutdown systems

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 Heysham 1 Integrated Intervention Strategy (IIS) for 2018/19, a planned SBI on shutdown systems (SBI-28) at EDF Energy Nuclear Generation Limited’s (NGL’s) Heysham 1 (HYA) power station was conducted on 5 and 6 March 2019. The purpose of this inspection was for ONR to determine the adequacy of implementation of the safety case claims in respect of shutdown systems.

Interventions Carried Out by ONR

As an ONR specialist inspector, internal hazards, I was accompanied by two further ONR specialist inspectors, and an ONR nuclear associate.  Our aim was to determine the adequacy of implementation of the Licensee’s safety case claims in respect of the Primary Shutdown (PSD), Secondary Shutdown (SSD) and Tertiary Shutdown (TSD) systems. We examined evidence to determine compliance against six 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:

The intervention was performed in line with ONR's guidance requirements (as described in our technical inspection guides) in the areas inspected.

We sampled and examined the applicable safety case claims, through a combination of document reviews, discussions with plant operators, internal nuclear assurance and plant inspections to determine compliance against the selected LCs.

The focus of this inspection was the consideration of the mechanical engineering and internal hazards aspects of the shutdown systems.

Key Findings, Inspector's Opinions and Reasons for Judgements Made

From the areas targeted and the evidence examined during the SBI, we considered that NGL has adequately implemented those safety case claims that relate to the shutdown systems. 

Licence Condition 10 (Training) – the training records for six personnel that fulfil roles associated with shutdown systems were sampled. NGL informed ONR that there is no specific training programme relating to shutdown systems and that training consists of engineering training and on the job training (OJT) in order to ensure an individual has the required skills for shutdown systems. All of the individuals sampled had completed the required essential training for the tasks sampled. 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) – ONR viewed a number of structures, systems and components (SSCs) related to the shutdown systems 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) – on the basis of the sampled documentation, including the Maintenance Schedule and Work Order Cards relating to the examination, inspection, maintenance and testing of shutdown systems 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.

Licence Condition 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) – on the basis of the sampled documentation and discussions with the Environmental Safety Group, NGL provided adequate assurance that all required records will be generated and maintained for the SSD system passing valves. I therefore assigned a rating of Green (no formal action) for LC34.

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 shutdown systems 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.