Office for Nuclear Regulation

Aldermaston (AWE(A)) Production Facility - System Based Inspection (SBI)

Executive summary

Purpose of Intervention

This intervention, conducted at the Atomic Weapons Establishment Aldermaston (AWE(A)) licensed site, was undertaken as part of the Office for Nuclear Regulation’s (ONR) 2018/19 intervention plan and the weapons sub-division strategy.

Interventions Carried Out by ONR

During ONR’s August 2018 site inspection week, accompanied by the ONR site inspector for PTC and a specialist mechanical engineering inspector, I supported a planned System Based Inspection (SBI) on a process in the AWE(A) Main Production Facility.  [Henceforth this inspection team is referred to as “we”].

Through the examination of a process within AWE’s Main Production Facility, we performed compliance inspections against a number of Licence Conditions (LC). 

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


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

Conduct of the SBI was via examination of documentation and records, discussion with key plant personnel and inspection of the relevant plant areas. The key findings against each LC are summarised below:

LC 10 (Training) – Rating = Green

The licensee evidenced satisfactory performance against its LC 10 arrangements, with respect to the conduct of the training associated with the process under inspection. However, advice was given to the licensee on the benefits of using approaches such as ‘train-the-trainer’ for its staff undertaking mentoring duties with a view to enhancing training outcomes.

We also observed adequate resilience within the licensee’s Suitably Qualified and Experienced Persons (SQEPs) and also in the associated Duly Authorised Persons (DAP) for this process. DAP resilience across facility processes as a whole, however, whilst an improving picture remains a concern to ONR.

We were content that overall this inspection merited a rating of ‘Green’.

LC 23 (Operating Rules) – Rating = Green

The line of sight from the safety case to the operating rules (OR) and their articulation in the plant operating instructions/shop floor documents etc. was clear and well explained. Operatives questioned had a good understanding of the ORs and the means of complying with them.

Overall, we judged that the LC23 part of our inspection merited a rating of ‘Green’.

LC 24 (Operating Instructions) – Rating = Green

The documentation sampled in this area was well written (identifying suitable hold points, warnings etc. and where applicable making good use of photographs and diagrams). There was good evidence of compliance with the operating instructions (OI), obtained during our plant walk-down, with documentation sampled being appropriately signed off. 

Overall we were content that the performance against this LC merited a rating of ‘Green’.

LC 27 (Safety Mechanisms, Devices and Circuits) – Rating = Green

Appropriate devices for worker protection were judged to be present and the LC28 part of our inspection confirmed that these were being appropriately maintained and inspected.

Overall we were content that the performance against this LC merited a rating of ‘Green’.

LC 28 (Examination, Inspection, Maintenance and Testing) – Rating = Green

During this inspection, maintenance and calibrations of key items of equipment associated with the process under inspection were seen to have been completed as required.

We noted however that more diligence could have been applied to completion of some of the maintenance records.  We identified that there were opportunities to either improve the proformas themselves and/or staff training in this area.  This has been identified to the licensee in previous SBIs and is an area of focus for the licensee with the Maintenance Manager himself taking a routine (monthly) sample of completed MIs (to obtain a view as to the quality of the completed documents).  In addition the licensee is currently undertaking a substantial exercise to improve work control in the facility.  Accordingly, we considered that no additional regulatory action was required at this juncture.

Some evidence of failure to routinely apply isolation tags was also observed, but the licensee was able to demonstrate that the deficiencies noted had already been identified and work was being undertaken to address them.

Overall we were content that the performance against this LC merited a rating of ‘Green’.

LC 34 (Leakage and Escape of Radioactive Material and Radioactive Waste) – Rating = Green

The licensee’s key line of defence against migration of radioactive material from the glove box containment is detection by the Continuous Air Monitors (CAM), placed in close proximity to the glove boxes. The licensee has an operating rule in place to ensure work does not proceed unless a defined number of CAMs are operational.

However, it was not clear how the placement of the CAMS had been derived and the licensee was able to provide no documentary evidence in this area. We did note however the licensee’s arguments that the facility is if anything oversupplied with CAMs, which may mitigate some of any placement risk and that the in-service history of the CAMs provides evidence that they are functioning as required. Nonetheless this is an issue which will be further followed up through ONR’s assessment of the licensee’s Periodic Review of Safety (PRS2) submission for the Main Production Facility (since the licensee has asserted that a review of CAM placement has been conducted as a part of this submission).

Noting the imminent timescales for submission of PRS2, we were content that the performance against this LC merited a rating of ‘Green’.

Conclusion of Intervention

From the totality of the evidence we sampled, plant walk-downs and from our interactions with key licensee personnel, we were satisfied that an overall inspection rating of ‘Green’ was appropriate.