Office for Nuclear Regulation

Atomic Weapons Establishment Aldermaston – Inspection ID: 50444

Executive summary

Date(s) of inspection:

  • January 2023

Aim of inspection

The aim of this inspection is to gather intelligence to determine progress against two regulatory issues relating to LC36.

The first issue (RI 10504) was raised to address remaining shortfalls following AWE failing to fully implement all actions required to address shortfalls covered in two LC36 Improvement Notices; this action requires the timely delivery of an adequate improvement plan, demonstration of executive commitment, as well as implement suitable governance and oversight arrangements.

The second Regulatory Issue concerns Baseline Vulnerability Management for the maintenance function (RI 10628), with actions agreed including internal benchmarking, review of baseline (including consideration of Facility Engineers and Reliability Engineers), vulnerability management, and presentation of a revised baseline to ONR.
The inspection is focussed on these two regulatory issues, and the inspection is to consider the adequacy of action implementation.

Subject(s) of inspection

  • LC36 – Organisational capability – Rating: Green

Key findings, inspector’s opinions and reasons for judgement made

This was the final inspection on AWE’s progress against the action plan raised following closure of theLC36  improvement notices ONR-IN-19-002 and ONR-IN-19-003. It also covered progress on associated regulatory issues 10504 (L2) and 10628 (L3). The intent was for ONR to judge AWE’s progress on delivery of its LC36 improvement plan (RI 10504), and the progress on resolution of an issue with management of the maintenance function nuclear baseline including vulnerability management (RI 10628). Previous interventions had been carried out in 2021-22, with the most recent being rated Green (May ’22: ONR-OFD-IR-22-016, Green; February ’22: ONR-OFD-IR-21-145; Amber; October ’21: ONR-COP-IR-21-096, Amber).

This intervention relates to Licence Condition 36 (LC36), which is concerned with how a licensee demonstrates that it has and will maintain adequate organisational capability to ensure safe operation of the licensed site. An evidence-based approach was taken to inform its regulatory judgement, and ONR engaged in discussion with relevant AWE HR personnel and maintenance representatives and sampled current arrangements.

I examined AWE’s progress on delivery of its improvement plan. This review focused on:

  • AWE’s LC36 arrangements.
  • Progress of outstanding actions on the LC36 improvement plan.
  • Sample of the outcomes required to demonstrate improvements in implementation of LC36 arrangements.
  • Follow-up of maintenance regulatory issue, including nuclear baseline, vulnerability management and the incorporation of Facility and Reliability Engineers on the baseline.

I judge that AWE have made adequate progress against its LC36 improvement plan, and that the combination of improved arrangements, performance metrics and improved governance and oversight arrangements provides a sound basis for AWE to manage their organisational capability. I judge that there was been sufficient progress on the extant regulatory issues to propose closure of these.

However in the course of the intervention maintenance could not demonstrate that their nuclear baseline included all relevant staff, or show how identified vulnerabilities are mitigated, so a new Regulatory Issue will be raised for this to be addressed In line with ONR’s guidance.

Based on the evidence sampled during this inspection, I judge that measured against ONR’s expectations that the intervention rating is Green.


I judge that AWE was able to demonstrate that it had made and implemented their improvement plan to demonstrate the outcomes necessary to address the residual gaps from the Improvement Notice work. This included:

  • Improved LC36 arrangements that meet RGP.
  • The Nuclear Baseline has been revised and developed in alignment with their arrangements.
  • Improved compliance with Management of Change arrangements, as well as improved link to the Nuclear Baseline.
  • Improved governance and reporting of LC36, including reports on vulnerabilities, and quality of MOCs.
  • Improving accountability for LC36 across the site.

This provided adequate evidence to propose closure of the Level 2 regulatory issue. Additionally, the actions sampled for the maintenance issue also provided sufficient evidence to propose closure of the issue raised for maintenance. However, in the course of the inspection the broader question concerning the adequacy of the nuclear baseline in maintenance could not be ascertained: the maintenance baseline could not be sampled, and the adequacy of vulnerability action plans to mitigate risks and justify baseline adequacy could not be seen. As such a regulatory issue will be raised to monitor progress in this area.

Taking the above into account, I rated the inspection ‘Green’ (No Formal Action).