Office for Nuclear Regulation

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Planned LC7 intervention

Executive summary

Purpose of intervention

This report covers interventions carried out as part of ONR’s regulation of operations undertaken at the Atomic Weapons Establishment in line with ONR Integrated Intervention Strategy for the Atomic Weapons Establishment Programme.

Interventions Carried Out by ONR

The planned LC7 intervention at the AWE Aldermaston site was primarily to review implementation of identified improvements and revisions to LC7 arrangements to demonstrate adequate compliance, by checking whether AWE had addressed the agreed actions to address an existing Regulatory Issue.

There was an intervention to discuss and compare compliance ratings across all licence conditions.

The licence condition was inspected against ONR’s published guidance requirements, as described in our technical inspection guides, which can be found at Office for Nuclear Regulation (ONR) Compliance inspection - Technical inspection guides. Further information on Integrated Intervention Strategy (IIS) ratings, is available at

Explanation of Judgement if Safety System Not Judged to be Adequate

Not applicable during this inspection.

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

From the evidence sampled during this inspection, which included the actions to address an existing Regulatory Issue and other identified improvements, for instance clarity of roles and responsibilities, enhanced training, particularly senior investigator training, which is ongoing and a more rigorous investigation and governance process, which includes local ESH reviews, I judge that AWE’s arrangements to comply with the requirements of LC7 are adequate in that they meet the majority of ONR’s expectations. Comments previously provided on earlier drafts of the arrangements had been addressed; minor comments to aid clarity and editorial points on the updated arrangements and advice on any rationalisation of documents were accepted. I noted that some recent investigation reports had not identified the root cause of the associated abnormal event, which AWE acknowledged, but noted that these were expected to become the exception when the process fully beds in. Therefore a rating ‘Green’ is appropriate with no formal regulatory action required.

Interim LC ratings at the mid-year point were presented to AWE, with an explanation of the reasons for the ratings. AWE said they understood our view and there was no disagreement on the day. These will inform the forthcoming Annual Review of Safety meeting and the Chief Nuclear Inspector’s report.

Conclusion of Intervention

The AWE LC7 corporate team has addressed the actions to close an existing Regulatory Issue and the ongoing improvements, if fully implemented, should ensure that the AWE LC7 arrangements and process continue to adequately address LC7 requirements. No formal regulatory action is required.

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