Office for Nuclear Regulation

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Planned Intervention: System Inspection - SBI24 Reactor Guardlines

Executive summary

Purpose of intervention

This intervention was a system based inspection which was undertaken to enable a judgement to be made on the adequacy of the duty holder's implementation of arrangements for the reactor guardline systems to comply with the requirements of the following Nuclear Site Licence Conditions (LCs):

This intervention also reviewed events reported to ONR under LC7 arrangements relevant to the reactor guardline systems.

Interventions carried out by ONR

Not applicable.

Explanation of judgement if safety system not judged to be adequate.

Not applicable.

Key findings, Inspector's opinions and reasons for judgements made

The aims of my inspection were to sample inspect the material condition of the reactor guardline systems and require that the licensee should explain:

I was satisfied that the duty holder has maintained a suite of technical specifications, surveillances, plant operating instructions, and plant maintenance instructions that through the asset management suite (AMS) work management system support delivery of the requirements in the Hartlepool safety case. During this intervention a selection of each of these documents and historical records of completed work order cards were sampled. This gave ONR confidence that the duty holder is implementing their arrangements and completing reviews of their documentation.

In the case of the secondary shutdown system channel gas outlet temperature settings I noted that the living safety case system based view did not capture a change originally proposed in NP/SC 3009 which changed the servo reset margin to ≤65°C from the 100°C setting originally given in the stage 3 safety report. The lower value is given in the relevant technical specification and the licensee has agreed to consider how best to capture this change in the living safety case system based view.

I found that the maintenance schedule referred to a stage 3 safety report rather than the living safety case system based view document and the nuclear safety group engineer agreed to review whether it was possible to adapt the documentation to address this shortfall. There is already a clear link established between the safety report and the living safety case system based view documentation.

I judge compliance with the implementation of the safety case requirements to be at a good standard.

Conclusion of intervention

I was satisfied from the activities sampled and evidence gathered during this intervention, that there are no matters, at this time, relating to the reactor guardline systems that are likely to have a significant impact on nuclear safety at HRA. I conclude that, with regard to the reactor guardline systems, the licensee is complying with relevant licence condition requirements and is applying the arrangements to a good standard (Rating 2).


The planned inspections and interventions set out in the Integrated Intervention Strategy for Hartlepool remain valid and will be followed for future inspections.