Office for Nuclear Regulation

Atomic Weapons Establishment Aldermaston – Inspection ID: 52732

Executive summary

Date(s) of inspection

  • August 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 ATC on the Burghfield 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 ATC Facility, I was supported by the ONR BNLS Site Inspector. The inspection focussed on seeking assurance that AWE/ATC 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.

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

The inspection team 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 the inspection teams 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 the opinion of the inspection team, 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 ATC 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 backlog, which comprised of planned deferrals as well as breakdowns, neither number was significant and the total was deemed ‘normal’ and represented a very small percentage of the total AWE backlog.  In addition plant availability was 100%.  However I was less certain that opportunities for learning were being adequately grasped as a result of investigating breakdowns.  I advised AWE that they could be doing more in this area.  On balance I was satisfied that the EIMT backlog in ATC was not a concern.

Staff capability.  Noting that the EIMT backlog was not an issue then it was implicit that ATC had access to adequate EIMT capability.  Notwithstanding this, I sampled 2 operators and noted that (i) AWE is not sighted on Emcor training details – this raised ‘Intelligent Customer’ questions, which I was told was already being considered by ONR; and (ii) a significant amount of AWE refresher training had a 12-month refresher period.  This period was significantly less than the rest of the industry, which worked on a mostly 3-year cycle.  An operator was noted as being out-of-ticket (due to illness) but had undertaken work following a return-to-work briefing.  I offered advice to AWE that they might want to re-consider their refresher training periods.  I was therefore satisfied that ATC had access to appropriate EIMT capability and, on balance, that capability was SQEP.

EIMT deferral.  ATC followed corporate arrangements to defer maintenance by use of the ACR process.  No deferred items were classed as having anything other than insignificant consequences as a result of having their maintenance deferred.  The process was sampled for 3 items that were on the ‘Green’ route with no issues being found.  I was therefore satisfied that the EIMT deferral process was adequate within ATC.

Storage facilities.  Storage facilities had been selected to sample because it had previously been noted that the correct environmental conditions for HEPA filters had not been maintained i.e. temperature and humidity.  HEPA filters were not stored in ATC and no other SSCs were identified that had similar environmental constraints.  It was noted that other items could be stored in a more logical fashion to facilitate expedient identification.  This advice was passed on to AWE.  On balance I was satisfied with the storage facility.

SSC labelling.  Labelling was recorded for several SSCs during the walkdown and then checked back in the office i.e. that the label conformed to the correct SSC in the Engineering and Plant

Maintenance Schedules.  This check was successfully completed.  I did note that labels were not very helpful regarding the safety significance of the item i.e. designations such as SFC1, 2 or 3 were not used.  AWE proposed to check that they were following their process correctly.  Nevertheless, I offered advice that labels could provide more information e.g. to alert the operator to the safety significance of the item.

Although some regulatory advice was given, I judge that overall there were no concerns with EIMT backlog; SQEP capability; the use of the EIMT deferral process; storage facilities; and the labelling of SSCs.  I therefore rate this inspection as Green.