Office for Nuclear Regulation

AWE Aldermaston – Inspection ID: 22-042

  • Site: AWE Aldermaston
  • IR number: 22-042
  • Date: June 2022
  • LC numbers: 28

Executive summary

Purpose of Intervention

This intervention, conducted at the Atomic Weapons Establishment’s Aldermaston site, was undertaken as part of the 2022/23 intervention plan and weapons sub-division strategy.

Interventions Carried Out by ONR

We conducted a planned Licence Condition 28 EIM&T “examination, inspection, maintenance and testing” inspection in the Plutonium Technology Centre at the Atomic Weapons Establishment’s Aldermaston site.  The focus of the Licence Condition 28 inspection was on examination, inspection, maintenance and testing of the active ventilation systems installed in the Plutonium Technology Centre.

The intervention was performed in line with ONR’s guidance requirements (as described in our technical inspection guides) in the areas inspected.

Explanation of Judgement if Safety System Not Judged to be Adequate

Not Applicable.

Key Findings, Inspector’s Opinions and Reasons for Judgements Made

Plutonium Technology Centre personnel provided us with an overview of the ventilation systems in the facility to support our knowledge for the inspection. We were introduced to the building information model that the facility uses to support their examination, inspection, maintenance and testing regime. As a part of the initial boardroom session, we were introduced to the facility’s arrangements for examination, inspection, maintenance, and testing. We were satisfied that the facility personnel were able to establish that the EIM&T carried out at the facility was linked to satisfying the requirements of the facility’s safety case. We noted facility personnel were able to establish this link despite the complex nature of the facility and had an in-depth knowledge of the arrangements and processes.

We undertook a walkdown of key areas in the facility where ventilation systems are operated. Facility personnel were observed to have a good understanding of the plant as we requested information on various plant items. We made minor observations on ad-hoc labelling and signage on the plant as well as mismatched plant instrumentation. Overall, we were satisfied with the general housekeeping and the condition of the facility where we conducted our walkdown.

We examined several maintenance schedule items and the corresponding work order cards/ maintenance instructions. We confirmed that maintenance was being undertaken in line with the intervals as specified in the maintenance schedule, and that for most cases this was completed in an adequate manner. However, from conducting our review we did find a few discrepancies. We observed in a work order card a recorded defect with a lack of a recorded forward action plan for tracking to completion. We also observed a discrepancy between maintenance intervals in the maintenance schedule and the facility’s asset management system. After further investigation and discussion with facility personnel we determined that the discrepancies were minor and that no significant shortfalls were present. No further regulatory action was necessary.

The facility has recently been affected by an issue which compromised the ventilation system in a particular area of the ground floor, which poses an asphyxiation risk. This issue is being managed through other regulatory and enforcement action (a Prohibition Notice) and as such was not considered in this LC28 inspection.  Hence the final rating of ‘Green’ relates only to the areas sampled in the inspection, and not to the ongoing issue of reduced oxygen.

Conclusion of Intervention

From the findings summarised above, from the totality of the evidence sampled and from our discussions with facility personnel, the overall Licence Condition 28 inspection was awarded a rating of GREEN.