Office for Nuclear Regulation

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ALARP Workshop

Executive summary

Purpose of intervention

From my assessment of the Heysham 1 and Hartlepool air receivers safety case I raised generic concerns over EDF Energy Nuclear Generation Ltd's (NGL) approach to, and presentation of, the demonstration that the level of risk had been reduced as low as reasonably practicable (ALARP).

The purpose of the intervention was to discuss my generic concerns on ALARP using the air receivers safety case as a case study.

Interventions Carried out by ONR

I attended a workshop with NGL at its Barnwood offices to discuss its approach and the presentation of ALARP. I considered NGL's approach to ALARP against the Office for Nuclear Regulation's Technical Assessment Guide (TAG) on ALARP, TAG 005."

Explanation of Judgement if Safety System Not Judged to be Adequate


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

This meeting was a useful discussion of the ALARP and optioneering processes used and the outputs produced by NGL. Following the meeting it was clear to me and the other attendees that NGL needs to change the way in which ALARP arguments are presented. A specific weakness is that more weight should be given to the practicability of options that eliminate the hazards and increase safety case robustness. The reasoning behind why options are screened out also needs to be supported by improved qualitative arguments which will help the reader understand why the option chosen is indeed ALARP.

It was agreed that the individual who presents the ONR ALARP training course and the individual who presents the NGL ALARP training would both benefit from attending each others course, to understand each others perspectives. They both undertook to investigate whether this was possible.

Conclusion of Intervention

I conclude that the meeting was an open, honest and useful opportunity to discuss the presentation of ALARP and optioneering by NGL. It was helpful to be able to use a case study as the basis for a discussion and I am confident that some important points were discussed which should improve the licensees representation of both optioneering and ALARP, ONR need to continue to influence the licensee regarding this issue.

Although there remains a fundamental difference in opinion in connection with ONR's expectation for implementing the safest option that is reasonably practicable, NGL considers its approach ultimately leads to the same outcome when all factors are taking into account, for example time taken to implement an option. Notwithstanding this, NGL agreed to reflect on the conclusions of its air receivers case, taking account of the discussion from the workshop.

NGL agreed that its presentation of ALARP could be improved, making clear the factors being considered in its decision making and summarising all options it has considered including those discounted and the basis of this.

NGL also agreed that it could provide additional emphasis in its ALARP training to reflect some of discussion points from the workshop.

Although some progress was made, there remain some differences between NGL's approach, as outlined in its guidance, and the guidance set out in ONR's ALARP TAG. Therefore ONR needs to continue to influence the licensee regarding this issue. A further workshop will be considered after ONR has observed NGL's ALARP training and NGL has observed ONR's ALARP training.