Office for Nuclear Regulation

Atomic Weapons Establishment Aldermaston – Inspection ID: 52733

Executive summary

Date(s) of inspection

  • October 2023

Aim of inspection

(NB this inspection will be combined with LOLER inspection IR-52801 (Liam Halse) to reduce the burden on the duty-holder – there will still be separate IRs written).

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 Waste and Decommissioning (W&D) 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 (DRO.1.5 – Demonstration of clear correlation between approved programme of work across the AWE Plc sites and the availability of SQEP [capacity and capability]; and DRO.5.3 – Improved delivery of the EIMT requirements to address the current maintenance backlog) 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 W&D Facilities, I was supported by the ONR W&D Site Inspector. The inspection focussed on seeking assurance that AWE/W&D is:

a) managing any maintenance backlog;
b) assigning adequate SQEP resource to EIMT activities; and
c) able to justify the deferral of any maintenance.

Prior to the LC28 inspection, I undertook a review of the relevant AWE arrangements for management of maintenance against the ONR guidance documents.  From the areas sampled, I did not identify any significant shortfalls in the licensee’s formal arrangements for compliance with LC28, which would prompt an inspection of these arrangements earlier than currently planned.

To judge the adequacy of the AWE’s management of maintenance at its waste and decommissioning facilities, I asked AWE to provide an overview of its current maintenance backlog. AWE provided information on its backlog. This demonstrated a downward trend in the total amount of open backlog, with no nuclear safety related EIMT items within the backlog identified.

The LC28 EIMT backlog has averaged at approximately 22 for the A1 complex over the last 2 years. Including conventional statutory inspections, the backlog has averaged about 40 over the same period. I reviewed the specific inspection backlog items and concurred that outstanding items were not significant from a nuclear/conventional safety perspective (most were civil aspects that could not be completed for valid reasons).

I also reviewed the breakdown trends. This included LC28 Inspection findings and operational breakdowns. The level of breakdown backlogs remains within a stable/manageable amount (around 150), with the majority being related to lighting / electrical systems. The lighting and electrical systems are being replaced with temporary lighting and power as the plant progressively becomes decommissioned.

AWE stated that capacity and capability to address EIMT backlog is not a concern. The waste and decommissioning facility is currently extending the capability of its maintenance teams so they can carry out maintenance task across other waste and decommissioning areas. I reviewed a sample of operator and supervisor training records, and confirmed these were adequate to support the activities inspected.

EIMT and repairs backlog items are currently prioritised, on nuclear safety significance. The process is currently being revised to consider the decommissioning status of the facilities. I was satisfied that the repairs backlog was demonstrated to be adequate within AWE’s existing site arrangements.


On the basis of the evidence sampled at AWE in relation to LC28, I judge that the licensee is adequately managing maintenance within the waste and decommissioning facilities. I consider relevant good practice to be generally met in comparison to the appropriate benchmarks. Therefore, I have assigned an inspection rating of GREEN (no formal action required).