Office for Nuclear Regulation

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Planned inspection at AWE Aldermaston

Executive summary

Purpose of Intervention

This intervention, conducted at the Atomic Weapons Establishment (AWE) Aldermaston licensed site, was undertaken as part of the 2017/18 intervention plan and weapons sub-division strategy.

Interventions Carried Out by ONR

During the Office for Nuclear Regulation’s (ONR) January 2018 site inspection week I attended routine briefing meetings with key licensee (i.e. AWE plc) personnel, to discuss the licensee’s progress with important safety related projects within the two inspection portfolios for which I am the ONR site inspector.

Additionally, supported by ONR specialist inspectors in fault studies and mechanical engineering, I conducted a planned System Based Inspection (SBI) in the AWE Aldermaston Main Production Facility.  Through examination of a production process 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

In the case of all the routine meetings I conducted with key licensee personnel (reported in the body of this report), no matters were identified as requiring additional regulatory attention.

Conduct of the production process 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 recorded below:

LC 10 (Training) - Rating = Green

The licensee evidenced satisfactory performance against its LC 10 arrangements, with respect to the conduct of training associated with the production process.  However, we advised that configuration management of training records needs ensuring (and ultimately the compatibility of local training matrices with the corporate ‘Minerva’ system records - we recognise that AWE’s transition to this system has been problematic).  Additionally, the production of training matrices for maintenance staff in the facility needs to be expedited, as does a site-wide initiative to identify maintenance training needs.

Since Duly Authorised Persons (DAP) supervisory interventions are conducted by ‘proxy’ i.e. via DAP involvement in the selection and appointment of trained operators and in the approval of the operating instructions, then we advised that a clearer line of sight is required to demonstrate DAP involvement in the approval/up-lifting of the operating instructions.

Notwithstanding the above advice, provided to the licensee, 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 and their articulation in the plant operating instructions/shop floor documents etc. was clear and well explained.

LC 24 (Operating Instructions) - Rating = Green

The documentation sampled in this area was well written and there was good evidence of compliance, obtained during our plant walk-down, with documentation being appropriately signed off on plant.  The licensee was quite clear that the Route Cards were the top level document but the linkage to the operating instructions was clear.

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

Appropriate devices for worker protection were judged to be present and the LC 28 part of our inspection confirmed that these were being appropriately maintained, inspected etc.

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

During this inspection, some spurious working practices were identified e.g. evidence was found of historical maintenance having been conducted against unapproved Maintenance Instructions (MI), or of maintenance being conducted to an MI referring to an earlier configuration of the plant that had since been modified.  Such instances need to be sought out and addressed.

However, the licensee was able to demonstrate that the deficiencies noted had already been identified and work was/had been undertaken to address them (e.g. the Work Coordination Centre will now not issue MIs unless they are at an approved status). The licensee also evidenced some areas of good practice e.g. the monthly ‘dashboard’ of the worst-performing plant equipment etc.  Overall we were content that the performance against this licence condition 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 glovebox containment is detection by the Continuous Air Monitors (CAM), placed in close proximity to the gloveboxes.  The licensee has an operating rule in place to ensure work does not proceed unless a defined number of CAMs are operational.  We sampled the licensee’s daily checks to ensure/confirm that the CAMs are suitably operational prior to work commencement and were satisfied that this system is robust.

Conclusion of Intervention

In the case of all the routine meetings I held in January 2018 Inspection Week; no matters were identified as requiring additional regulatory attention.

For the production process systems based inspection, from the totality of the evidence we sampled, a plant walk-down and from our interactions with key licensee personnel, we were satisfied that an overall inspection rating of ‘Green’ was appropriate.