Office for Nuclear Regulation

Atomic Weapons Establishment Aldermaston – Inspection ID: 52088

Executive summary

Date(s) of inspection:

May 2023

Aim of inspection

To judge the adequacy of AWE’s implementation of its arrangements made under LC 26 from a control of contractors work perspective.

Subject(s) of inspection

  • LC 26 – Control and supervision of operations – Rating: GREEN

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

This intervention also aimed to obtain evidence towards closure of the outstanding Level 3 regulatory issue, on control and supervision, against the Atomic Weapons Establishment Plc.

The inspection was conducted over one day in the Plutonium Technology Centre, and was completed in collaboration with the licensee’s Internal Regulator.

We found that control of work management arrangements were understood and were being used effectively for the tasks that we sampled. The licensee personnel we spoke to were able to convey their roles and responsibilities, as well as how they supported safety. We observed good use of additional administrative work controls in the Work Coordination Centre. We also observed that third party service providers understood, and would be comfortable using, the licensee’s “stop work authority” if they felt unsafe.

No major findings were noted during the course of the inspection. Some minor procedural issues were observed during the intervention related to electrical isolation permits and Point of Work Risk Assessments. No formal action was judged to be necessary in response to these minor issues. Regulatory advice was provided to the licensee and the licensee committed to providing refresher briefs to third-party service providers working in the facility.


We judge that the licensee has adequately demonstrated compliance against LC26 – control and supervision of operations for the chosen sample; meeting relevant good practices and providing supporting evidence; and following their own MSP702 work control arrangements. Specifically, we note that where we sampled, our expectations (derived from the TIG for LC 26 – ONR Ref. No.’s NS-INS-INSP-GD-026) were met; for example:

  • Relevant training and site inductions for contractors undertaking work on the licensed site.
  • There are adequate provisions for the physical control of the work (lockout boxes, overrides, temporary fits, isolations, etc.) and the work packages and visual aids contained in isolation permits reflect the status of these provisions.
  • Inclusion of appropriate risk assessments, completed by SQEPs, which account for conventional, as well as nuclear safety.
  • Adequate systems and arrangements for understanding plant states to support planning of work, coordination of work fronts and authorisation of work.
  • There is a satisfactory balance in supervisor’s duties to permit adequate observation and interaction with the work teams in comparison with paperwork and administration duties.
  • Appropriate daily work meetings with relevant stakeholders which provide sufficient focus on facility status and safety.
  • Visible and accessible supervision at the workface to ensure safety is maintained whilst tasks are being delivered.
  1. We therefore consider, noting the ONR guidance on inspection ratings, that an inspection rating of GREEN (no formal action required) is merited for the licence condition inspected.
  2. The outcomes from this inspection will form part of the body of evidence which is taken to the programme sub-board with regards to the closure of RI 8100.