Office for Nuclear Regulation

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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:

System Based Inspection [SBI] 11 – Fire detection, suppression, barriers, doors and dampers. A technical specialist associated with SBI-11 provided assistance in performing this element of my inspection.

In addition I attended an ONR issues database meeting with Nuclear Safety Group in which we discussed the current regulatory issues affecting Hunterston B. 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 fire detection, suppression, barriers, doors and dampers 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 LC9 inspection focussed on contractor induction arrangements and the extent to which Doosan-Babcock is subject to audit from NGL. Doosan’s role compliance matrix for contract staff was broadly up-to-date against mandatory site training arrangements. NGL’s supply chain manager committed to review extant audit arrangements against contractor role compliance matrices in light ofeedback that audit had not been undertaken since 2012.

I met with the plant life extension manager who has responsibility for managing station interface with the Western Link and Hunterston East project. I sought an update from previous discussions on what arrangements would be implemented for instruction to itinerant contractors on site emergency arrangements, in particular requirements for muster when working within the site boundary at the 400kV station. I was satisfied that station has proposed pragmatic and fit-for-purpose arrangements; in particular the requirement for Iberdrola to operate with as few itinerant contractors as practicable thus simplifying arrangements for contractor accountancy in the event of a site incident. I was satisfied that station has appropriate induction arrangement in-place. Accordingly I have awarded an IIS rating of 3 – Adequate for LC9. 

The LC35 compliance inspection:

I judged that Hunterston B is working to clear and effective arrangements under LC35, appropriate for its phase of generating life. I judged that the station has appropriate level of resource interfacing with NGL’s liabilities unit; I concluded it is now timely to enhance frontline regulatory oversight of station baseline decommissioning plans as they continue to evolve ahead of the next submission to NDA in 2016 and beyond. This aligns to an existing strategic outcome within the CNRP operating reactor sub programme strategy published in 2014.

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. As a result I have scored this element of the inspection with an IIS Rating of 3 – Adequate.

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 fire protection systems was articulated well by NGL staff and consistent with safety case documentation. Accordingly I rated these elements of inspection as 3 – Adequate.

From an LC27 perspective, we observed demonstrable investment in fire detection systems; however we judged the surveillance and commitment to investment on key suppression systems to be less transparent. I have rated this element of inspection as 4 – Below Standard and raised two ONR issues through which to monitor improvements.

From an LC28 perspective, all Examination, Maintenance, Inspection and Testing (EMIT), entries sampled had been recorded as complete. We observed a variable standard with which check-sheets had been completed, particularly where the work instruction gave a requirement to make an explicit written record of condition or verification that pre-requisite checks have been carried out. However we observed that the electronic record does not in all cases provide a full record of the pre-requisite and ‘as-found’ condition as required by individual work instructions examined in the sample.

Station was requested to expedite a previous commitment to address the backlog of scanned in documents across the station. Also, in light of the variability of standard to which EMIT check-sheets are completed, NGL is to generate an explicit position statement on what constitutes the ‘full and accurate report’ of EMIT as required under Licence Condition 28(9). In light of these observations I have rated this element of inspection as 4 – Below Standard and raised one regulatory issue. 

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 LC9 and LC35. With regards to the system based inspection, after considering the evidence and on balancing relatively minor shortfalls against two licence conditions, I judge that the fire detection, suppression, barriers, dampers and doors system meets the requirements of the safety case and its’ implementation is deemed adequate. I have raised three regulatory issues by which to follow-up these shortfalls in compliance. 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.