Office for Nuclear Regulation

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Planned Inspection of Hunterston

Executive summary

Purpose of intervention

The purpose of this intervention was to observe and evaluate the annual Level 1 Emergency Exercise and the Annual Review of Safety at EDF Energy Nuclear Generation Limited's (NGL's) Hunterston B power station (HNB). The intervention was undertaken in line with the planned inspection programme contained in the HNB Integrated Intervention Strategy (IIS). It was carried out by the nominated site inspector, the nominated site inspector for Hinkley Point B, the Superintending Inspector for Operating Reactor delivery programme, and two specialist inspectors.

The site visit also constituted the handover for the new nominated site inspector at HNB, which took effect on 1st April 2014.

Interventions Carried Out by ONR

The ONR inspection team undertook a tour of the Radiological Controlled Area for familiarisation and to examine areas of major plant investment ahead of the Annual Review of Safety.

NGL presented its Annual Review of Safety report , which provided an overview of safety performance for the previous year and identified planned improvements.

On 3rd April 2014, HNB carried out the annual demonstration of its emergency arrangements required under Licence Condition 11 to a team of ONR inspectors.

Explanation of Judgement if Safety System Not Judged to be Adequate

No safety system inspection was undertaken, hence this is not applicable.

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

Whilst not a planned inspection of the RCA we saw evidence of significant investment in the facility; much improved arrangements for Foreign Material Exclusion (FME) and an evident pride in the operational team.

We considered NGL's fleet-wide testing and rotation of its emergency exercise matrix on a five year rolling programme to be a positive development. We acknowledged the progress being made by the site towards more challenging and diverse scenarios which has justified a reduction in regulatory resource attending exercises in recent years.

We judged that the Level 1 scenario was highly testing of emergency responders in relation to the large number of missing persons and uncertainty over location and extent of breach simulated during the exercise. During the course of the exercise a number of opportunities for improvement were identified. ONR has written to NGL requesting confirmation of the action proposed, or already taken, to address the points raised by ONR, together with those of their own staff and independent assessment team.

The nominated site inspector the nominated site inspector will engage with NGL and the company internal regulator during pre-exercise planning to seek assurance of appropriate variation and sufficient challenge in the 2015 scenario against the NGL exercise matrix.

During the Annual Review of Safety we noted HNB's strong safety performance with greater than three years with no significant safety events [defined as 'top tier' within the licensee's arrangements].

ONR welcomed the evident attention to plant investment as positive evidence of commitment to asset management. Many of the investments address, or will address, safety case improvements. We recognised progress with replacement of super-articulated control rods and improvements associated with the boiler tube failure safety case and the nitrogen plant.

Conclusion of Intervention

Overall, ONR considered the exercise to be an adequate demonstration of Hunterston B's emergency arrangements. All aspects of the emergency arrangement as detailed in the exercise scenario were satisfactorily demonstrated.

ONR considers HNB's Annual Review of Safety to constitute an appropriate reflection of its safety performance during 2013. ONR will continue to monitor performance during routine inspection, permissioning and project interactions.