Office for Nuclear Regulation

Atomic Weapons Establishment Aldermaston – Inspection ID: 52735

Executive summary

Date(s) of inspection

  • September 2023

Aim of inspection

To assess:

1. the effectiveness of AWE’s strategy for the management of maintenance of safety significant Structures, Systems and Components (SSCs) in response to the reduced capacity and capability of SQEP maintenance resource, and

2. the implementation of that strategy across the key operational areas across both sites to demonstrate compliance against the requirements of LC28 and the regulatory expectations defined within ONR’s NS-INSP-GD-028 (Version 8.1).

Subject(s) of inspection

  • LC28 – Examination, inspection, maintenance and testing – Rating: Green

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

This inspection at PTC on the AWE Nuclear Licensed Site was undertaken as part of a programme of planned inspections across a number of AWE facilities for 2023/24. The scope of the intervention was aligned to the ONR/ AWE Strategy and was to judge the adequacy of AWE’s implementation of its arrangements made under LC 28 with a focus on the management of maintenance backlogs.

I, a Mechanical Engineering Specialist Inspector for the ONR Weapon’s programme, undertook a Licence Condition 28 (Examination, Inspection, Maintenance and Testing (EIMT)) inspection at the PTC Facility, I was supported by the ONR PTC Site Inspector. The inspection focussed on seeking assurance that AWE/PTC is:

a) managing any maintenance backlog;
b) assigning adequate SQEP resource to EIMT activities;
c) able to justify the deferral of any maintenance; and
d) managing stores effectively and ensuring that SSC labelling is fit for purpose.

I carried out an LC28 compliance inspection at the AWE Nuclear Licensed Site, PTC facility.  I reviewed the management arrangements for LC28 and was able to establish the “golden thread” in the management system for this LC.

I sampled the evidence for maintenance backlogs; staff capability for undertaking EIMT; the deferral process for not undertaking maintenance; the local storage facility; and SSC labelling, and from these interventions, it is my opinion that the procedures and controls evidenced by AWE demonstrated that Relevant Good Practice had been observed and AWE was following its own procedures and that the requirements of LC28 had been satisfied.  AWE presented a clear auditable trail for all of the area’s sampled and demonstrated good control of documents, records and certifications.

In my opinion, the Licensee’s arrangements for compliance with LC28 are adequate.  I, therefore, conclude that this inspection identified no matters that may impact significantly on nuclear safety and, noting the ONR guidance on inspection ratings, that an inspection rating of GREEN (no formal action required) is merited for this licence condition inspected. The PTC Safety Case Manager accepted my judgment at the wash up meeting.


The intervention sought to sample certain areas associated with LC28.  These were: EIMT backlogs; staff capability; the process of deferring EIMT; storage facilities; and SSC labelling.  These will be considered individually based on the evidence presented:

EIMT backlogs.  Evidence was presented that showed up-to-date backlog information.  Whilst there was a significant backlog, which comprised of planned deferrals as well as breakdowns, it was not a huge number when compared against the number of assets being maintained.  In addition a ‘pause for safety’ had contributed to the backlog.  AWE was able to show that the backlog was well understood and being managed appropriately.  On balance I was satisfied that the EIMT backlog in PTC was not a concern.

Staff capability.  I noted improvements in EIMT capability as a result of ‘Project Glasgow’, specifically, the introduction of a Principal Maintenance & Reliability Engineer.  I also noted that 5 further M&RE posts underneath the principal M&RE were vacant, which meant that some improvements/ EIMT optimisation was not being realised.  It was also clear that AWE relied heavily on EMCOR resources to undertake EIMT activities and that these resources were not always available.  IR-52730 had identified that EIMT capacity was a known corporate issue that was being addressed.  On balance I was therefore satisfied that PTC was managing EIMT capability/capacity appropriately.

EIMT deferral.  PTC followed corporate arrangements to defer maintenance by use of the ACR process.  The process was sampled for 2 items with no significant issues being found.  I was therefore satisfied that the EIMT deferral process was adequate within PTC.

Storage facilities.  The A89.2 storage facility was inspected during the plant walkdown and items were found to be correctly identified and stored according to the AMS.  I was therefore satisfied with the storage facility.

SSC labelling.  Labelling was recorded for several SSCs during the inspection and then checked during the walkdown and found to be correct.  No instances of legacy or incorrect labels were noted.  I was therefore satisfied with SSC labelling.

I judge that overall there were no concerns with EIMT backlog; EIMT capability/capacity; the use of the EIMT deferral process; storage facilities; and the labelling of SSCs.  I therefore rate this inspection as Green.