Office for Nuclear Regulation

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Hunterston A follow-up inspection

Executive summary

Purpose of intervention

This intervention was a follow-up to an intervention ONR carried out at Hunterston A in January 2015 (IR-14-190, TRIM 2015/36223).  This resulted in a Level 3 regulatory issue (Ref 3270) being raised for the site to raise the standard of its event investigations (in particular root cause analysis and consideration of human factors) to that required by Magnox Limited (Magnox) corporate standards and relevant good practice.

The purpose of this intervention was to determine whether or not the site had made the necessary improvements and hence whether the Level 3 issue could be closed.

Interventions Carried Out by ONR

The intervention comprised the following elements:

The basis for the intervention was Licence Condition 7 (requirement for the licensee to make and implement adequate arrangements for investigation of incidents) and relevant good practice, in particular Technical Inspection Guide 7 and Health and Safety Executive guidance HSG 24.

The intervention was carried out by a specialist inspector in organisational capability and a specialist inspector in conventional health and safety.

Explanation of Judgement if Safety System Not Judged to be Adequate


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

In my opinion four of the six investigations I sampled in the course of this intervention fell below relevant good practice in identifying root causes and /or actions to prevent recurrence.  For example:

The Magnox root cause investigation into the cross-site transport event did not explicitly state the root cause(s) and did not fully explore the time pressures and inadequate work control and coordination (between projects, maintenance and contractors) evident in this incident.

The Magnox root cause investigation into the reactor roof works event (construction office not informed) did not clearly define the root cause(s), in particular why the site’s contractor oversight arrangements were bypassed in this case.

The Balfour Beatty investigations into the hand injury and work outside the scaffold did not adequately address why the events occurred in particular why the work planning process (including risk assessment and method statement) did not identify and / or effectively mitigate the hazard.

Both of the above Magnox investigations took over 10 months to complete (from the date of the event to the date of approval / authorisation of the report) which I do not consider timely.

Factors contributing to the shortfall in investigation quality appear to be:

Inadequate direction and / or support from management to those carrying out the investigation;

Both Magnox and Balfour Beatty acknowledged these shortfalls.

In the course of the intervention I found evidence of recent improvements by Magnox in its arrangements for event investigation.  This included a decision to allocate the Environment, Health, Safety, Security and Quality (EHSSQ) Manager as the sponsoring manager for all root and apparent cause investigations, in order to drive greater ownership of investigations and better communication of problem statements and terms of reference.  Magnox also has a wider operational experience improvement plan (informed by ONR’s intervention, its own peer assist process and other sources) which is part way through completion.  The improvement plan contains relevant actions but these are not all ‘SMART’ (Specific, Measurable, Achievable, Relevant and Timely).

I also observed a number of good practices during the course of the intervention, including:

Conclusion of Intervention

I conclude from my intervention that, while there is evidence of improvement (either in place or planned), Magnox has not yet made sufficient progress towards the standard of investigation required by its own corporate documents and relevant good practice.  In my opinion therefore the existing Level 3 regulatory issue should remain open.

To address the shortfall I will write to the Hunterston A Closure Director to request a SMART improvement plan to address the compliance gaps in both Magnox and Balfour Beatty’s investigation arrangements.  I will request that this includes the necessary assurance activities by which Magnox Limited and Balfour Beatty will themselves judge whether the required standard has been achieved.  This improvement plan will provide the basis for further follow-up interventions by ONR as necessary until the Level 3 issue can be closed.