Office for Nuclear Regulation

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Planned Intervention at Hunterston B

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at Hunterston B power station in line with the planned inspection programme contained in the Hunterston B Integrated Intervention Strategy (IIS). This intervention was carried out by the nominated site inspector, a supporting site inspector and a radiation protection specialist inspector.

Interventions carried out by ONR

As part of this intervention, we carried out compliance inspections against Licence Conditions (LC) 10: Training, LC12: Duly authorised and other suitably qualified and experienced persons, LC8: Warning notices, and Ionising Radiations Regulations 1999 (IRR99). Our inspections were based on sampling of the arrangements in place and their implementation. We held pre- and post- inspection meetings with the site management where the inspection agenda was discussed and content of this report was communicated. We also attended a site stakeholder group meeting, a meeting with the site inspectors from the EdF Safety and Regulation Division (SRD) and reviewed ONR's issues database.

Explanation of judgement if safety system not judged to be adequate

No safety system inspections were carried out on this visit.

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

Our inspection of arrangements made under LC10 and 12 showed that the licensee has adequate arrangements in place for compliance with these licence conditions. The licensee has developed a post training profile for all nuclear safety related posts. We undertook a sample inspection of training profiles for maintenance technicians; reactor desk engineers and emergency preparedness engineer and found these to be satisfactory. We also sampled authorisation certificates for two reactor desk engineers and found that they were adequately completed and were in date. We have assigned an IIS rating of 3 (Adequate) to this inspection.

Our inspection of arrangements made under LC8 showed that the licensee has adequate arrangements in place for compliance with this licence condition detailed within a local site specific procedure until the corporate procedure is revised and reissued. We inspected the Cooling Water (CW) Pumphouse and an emergency muster point and noted that appropriate notices were displayed as required by the arrangements. We have assigned an IIS rating of 3 (Adequate) to this inspection.

An ONR specialist radiation protection inspector undertook an inspection of the site arrangements for compliance with IRR99 by sampling the arrangements during the interim Reactor 3 outage and through an inspection of sealed source accounting and leakage tests. The arrangements and their associated implementation were found to be to a good standard and we have therefore assigned an IIS rating of 2 (Good) to this element of the inspection.

The licence conditions were inspected against ONR's published guidance requirements (as described in our technical inspection guides, which can be found at in the areas inspected. Further information on intervention ratings is available at

Conclusion of intervention

The sample inspections undertaken against LC10, 12 and 8 found that in the main Hunterston B's arrangements were adequate and were being implemented appropriately.

The sample inspection undertaken against IRR99 identified areas of good practice.

There are no findings from this inspection that could significantly undermine nuclear safety.


There are no recommendations from this inspection.

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