Office for Nuclear Regulation

Hunterston B planned intervention

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition [LC] compliance inspections at EDF Energy Nuclear Generation Ltd’s [NGL’s] Hunterston B power station, in line with the planned inspection programme contained in the Hunterston B Integrated Intervention Strategy [IIS] for 2014/15.

Interventions Carried Out by ONR

This intervention included compliance inspections against the following Licence Conditions:

In addition, I attended a bi-annual meeting of the Hunterston Emergency Planning Consultative Committee at Prestwick Airport. I also met with the station’s independent nuclear assurance evaluators for routine monthly discussions.

Explanation of Judgement if Safety System Not Judged to be Adequate

The shutdown systems were judged to meet the requirements of the safety case and were judged to be adequate.

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

The LC7 compliance inspection:

I observed that the station is compliant with its arrangements for categorisation of incidents and arrangements for reporting incidents to ONR. In one sample taken, the station had not raised an ONR Incident Notification Form [INF1] for an incident that occurred in December 2014 that otherwise met the criteria. However, I was assured this was a borderline case; the station has committed to sentence future such cases on a conservative basis.

I sampled two significant adverse condition investigation reports for two incidents in December 2014 and judged them to be of an acceptable standard. In each case, I considered the underlying root cause analysis and subsequent corrective actions were appropriate.

The system based inspection examined compliance against Licence Conditions 10, 23, 24, 27 and 28.

From an LC10 perspective we were satisfied that training and development of staff was effectively controlled and that operations were overseen by suitably qualified and experienced persons. We observed good practice in the use of training organisational learning reports to ensure training of SQEP staff in the fuel route embeds operational experience. As a result I have scored this element of the inspection with an IIS Rating of ‘2 – Good standard’.

From an LC23 and LC24 perspective, I judged that the operating rules and associated instructions to be well understood and embedded in the context of the system inspected. The overall safety envelope and philosophy of Shutdown systems was articulated well by NGL staff and consistent with safety case documentation. The inspection identified the need for further analysis of core reactivity models to underpin continued safe generation as part of the next routine periodic safety review. I rated these elements of inspection as ‘3 – Adequate’.

From an LC27 perspective, we observed an acceptable standard of Shutdown system health review and overall management; all safety mechanisms examined were available and in good working order. I have rated this element of inspection as ‘3 – Adequate’.

From an LC28 perspective, all Examination, Maintenance, Inspection and Testing (EMIT) entries sampled had been recorded as complete and full records available in the station’s asset management system. We identified minor shortfalls in quality associated with records which have been raised to the station’s attention.  I have rated this element of inspection as ‘3 – Adequate’.

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

Conclusion of Intervention

I am satisfied that station is demonstrably compliant with arrangements made under LC 7. With regards to the system based inspection, after considering the evidence and on balancing the need for some further analysis of core physics, I judge that the Shutdown system meets the requirements of the safety case and its’ implementation is deemed adequate. I have raised two regulatory issues for subsequent follow-up. In addition, further observations made during the inspection are to be addressed by NGL under their own arrangements and will be considered as part of routine regulatory business.

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