Office for Nuclear Regulation

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Hunterston B Licence Condition (LC) compliance inspections

Executive summary

Purpose of intervention

The purpose of this intervention was to undertake Licence Condition (LC) compliance inspections at EDF Nuclear Generation Limited's (NGL) Hunterston B (HNB) power station in line with the planned inspection programme contained in the Hunterston B Intervention Plan. Two further inspections were carried out in accordance with a fleet intervention and a readiness inspection. The compliance inspections and information exchange meetings were carried out by the Nominated Site Inspector; other inspections were led by a specialist human factors inspector, a specialist fuels inspector and a specialist Control and Instrumentation (C&I) inspector.

Interventions Carried Out by ONR

As part of this intervention, I undertook planned compliance inspections of Licence Condition 22 and Licence Condition 34. I also undertook information exchange meetings relating to statutory outage preparation; routine planned discussions with Station's Nuclear Inspection & Oversight team and a familiarisation tour of the Western Link project. I also attended the quarterly Site Stakeholder Group meeting.

A specialist human factors inspector undertook an inspection of Procedural Use & Adherence (PU&A) as part of a fleet-wide intervention.

A specialist Control and Instrumentation (C&I) inspector and a specialist fuels inspector undertook a readiness inspection for Reactor 4 Channel 12:80 fuel assembly recovery project.

Explanation of Judgement if Safety System Not Judged to be Adequate

There was no safety system inspection carried out during this intervention.

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

NGL provided a tour of the Western Link construction zone and has undertaken close cooperation with the principal contractor to secure assurance that the extensive earthworks do not pose an intolerable increase in flood risk or degradation in drainage capability. I was assured there exists a good level of cooperation with the principal contractors.

Procedure quality, use and adherence inspection - from the evidence presented, the IIS rating assigned to LC 24 is 4 (below standard), due to a sustained level of procedure related deficiencies at station, which are impacting on important issues e.g. plant alignment and Technical Specification compliance. I consider that whilst good work is being undertaken by HNB, a clear overarching strategy and plan is required with supporting work streams. These are required to co-ordinate and direct the work in order to ensure it is delivering the necessary improvement within appropriate timescales. This should build on and support the valuable work of the Station Procedures Support Team and supplement it with appropriate checks and metrics to track performance. I further consider that the strategy and work in this area would benefit from further involvement and support by senior management. Accordingly, I have raised an action on HNB (which I will track to closure via an Issue on the ONR Issues Database).

The inspection conducted was intended to review the licensee's readiness to deploy a project designed to safely recover a fuel assembly (located in R4 channel 12:80), which previously stuck on retrieval from the reactor at the last interim outage in March 2013 and which subsequently had to be re-seated in the reactor. The inspection consisted of a plant visit, examination of licensee documentation and discussions with key project personnel and was constructed around a number of Licence Conditions (LCs). Although we were cognisant that the inspection was being conducted early (since the project will not be deployed until August 2014), we considered, from the advanced stage of the project detailed within the licensee's evidence, that good progress has been made. We raised no nuclear safety issues with the licensee with respect to the current status of the project, but highlighted a number of areas we wished to see completed, prior to project deployment. The licensee in all cases was well aware of these areas for completion and was able to commit to firm timescales to supply remnant information to ONR to evidence their closure. We judged that the overall outcome of the inspection had been adequate and hence merited an associated IIS rating of 3 - Adequate.

From an LC34 perspective I judged that HNB has made adequate progress towards implementing the new company arrangements issued in March 2014. Radioactive leaks are managed, prioritised and sentenced appropriately; however further work is needed to align the categorisation of radioactive leaks with the rest of the fleet. Based on samples taken I judged NGL to have implemented its arrangements adequately, warranting an IIS rating of 3 - Adequate.

From an LC22 perspective, I judged that the HNB arrangements are demonstrably aligned to company arrangements. I observed three aspects of the arrangements associated with requesting licence instruments from ONR to require improved clarity, an observation upheld by recent difficulties in submission of licence instrument request. HNB has referred those observations to the Station process owner for discussion with the corporate centre. Based on the samples of Engineering Changes taken during the inspection I judged NGL to have implemented its arrangements adequately, warranting an IIS rating of 3 - Adequate.

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

The licence conditions were inspected against ONR's published guidance requirements (as described in our technical inspection guides).

Conclusion of Intervention

I judged NGL to be compliant with its arrangements under LC22 and LC34, justifying ratings of 3 - Adequate.

We judged the 12:80 project to be in an advanced stage of readiness and have obtained firm commitments from the licensee to supply remnant information, in appropriate timescales, to close off a number of areas where work is still ongoing. The licensee's supply of the remnant information will be tracked as a part of the routine regulatory oversight of the project augmented by a high level of project oversight provided by the licensee's internal regulator. Accordingly, we judge that the overall inspection merits an IIS rating of 3 i.e. Adequate.

From the evidence presented during the procedure quality, use and adherence inspection, the IIS rating assigned to LC 24 is 4 (below standard) and accordingly an action has been placed on the station and this will be tracked to completion via a level 3 Issue on the ONR Issues database.