Office for Nuclear Regulation

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AWE Aldermaston - Reactive System Based Inspection (SBI)

Executive summary

Purpose of Intervention

AWE plc wish to implement a revised reference safety case/Safe Operating Envelope (SOE)/Authority to Operate (ATO) in its A** Legacy Production Facility (Hold Point HP117 on UTC’s Hold Point Control Plan - HPCP).  AWE presented its reasoning for the implementation of the new reference safety case/SOE/ATO and the benefits that this would deliver at a meeting with Office for Nuclear Regulation (ONR) inspectors, in Bootle in September 2018.  Based on this presentation, a flexible permissioning approach to the lifting of HP117 (i.e. via a targeted inspection) was proposed to ONR’s Delivery Lead for the Weapons Sub-Division and was agreed.  The purpose of this intervention is hence to deliver that targeted inspection i.e. to provide the evidence to allow ONR to lift HP117, allowing AWE to implement its revised reference safety case/SOE/ATO in the A** Legacy Production Facility.

Interventions Carried Out by ONR

A reactive inspection, using the System Based Inspection (SBI) structure, was performed in the A** Legacy Production Facility, to provide evidence to inform ONR’s lifting of HP117.  The inspection was conducted as an SBI, since it allowed compliance inspections to be conducted against six separate licence conditions, maximising scrutiny of the licensee’s proposed implementation of its new revised reference safety case/SOE/ATO.  I conducted this inspection accompanied by ONR specialists in nuclear liabilities and human factors (HF); this inspection team is referred to as ‘we’ throughout this intervention record.

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

This SBI was the first part of a two part staged permissioning process and studied those aspects of the licensee’s implementation process currently in place, but recognised that some of the licensee’s implementation process is still in development.

From the evidence sampled during the conduct of this SBI, we were content with the licensee’s broad descriptions of the processes it is intending to use to implement the new reference safety case/SOE/ATO.  However, as some of it is the licensee’s work is still in progress, accordingly we intend to sample again in the first Quarter of 2019. Because the licensee’s work remains ongoing, at this stage we were obliged to rate this inspection as Amber.

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

Conduct of the reactive SBI inspection was via sampling of licensee documentation, a presentation provided by the licensee, a plant walk-down in the A** Legacy Production Facility and discussions with key licensee personnel.  The key findings, across each of the six LCs considered, are reported below:-

LC 10 (Training) – Rating = Amber

Whilst the licensee presented a slide indicating that consideration had been given to which members of the facility staff would need training in the new safety case/SOE/ATO and how this would be delivered, there was no training schedule, no training material to sample and no indication that the training design, delivery etc. would be as per AWE corporate requirements.  We advised the licensee that its forthcoming SOE workshops need to generate a training schedule and that clear learning objectives need to be established and that the competency of the staff in the new safety case/SOE/ATO must be demonstrated.  This will be sampled in our second inspection in the first Quarter of 2019.

LC 23 (Operating Rules - OR) – Rating = Amber

The new safety case has designated a suite of Limits and Conditions (L&Cs) and the licensee’s Golden Thread documents sampled show clearly where the L&Cs have come from and how the L&Cs are implemented.  However, where the Golden Threads point to a document (in which an L&C is implemented), it is not clear where precisely in the document the L&C is implemented.  We noted that as the SOE is not yet suitably mature, then it is not possible to make a judgement that the L&Cs eventually appearing in the plant documentation will be appropriate and will meet ONR expectations (since the wording currently presented in the Golden Threads could change).  We will sample the final L&Cs during our second inspection.

We also noted the licensee’s assertion that none of the L&Cs required to be designated as ORs under AWE’s procedures; we did not test this assertion on this occasion but will sample in this area during our planned second inspection.

LC 24 (Operating Instructions - OI) – Rating = Amber

We sampled a number of OIs and were content that the licensee was able in each case to provide a demonstration of compliance with the OI.  However, ONR’s HF inspectors advised that significant improvements could be made to the OIs to bring them in line with relevant good practice (RGP.

We also noted that the licensee could not present a clear map showing where Key Safety Actions (KSA), or Safe Operating Instructions (SOI) are implemented.  We recognised that the licensee has an opportunity going forward to produce a map, showing exactly where this information can be found and will ensure that the licensee has taken this opportunity during our second inspection in 2019.

LC 27 (Safety Mechanisms, Devices and Circuits) – Not rated

We did not sample in this area, since the licensee asserted that the requirement to specify new SMDCs would be decided as part of its ongoing Facility Safety Justification (FSJ) work.  No new SMDCs are specified as a result of the new reference safety case/SOE/ATO and those SMDCs, to be retired as a result of implementation of the new reference safety case/SOE/ATO, are those associated with processes that are now redundant in A**.

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

From the presentation provided by the licensee against this LC, we observed that the process for defining an unused piece of equipment in the facility and for reducing the L&Cs and Examination, Maintenance, Inspection and Testing - EMIT activities, associated with this item, was unclear as yet.  The licensee conceded that this was still a work in progress.  Once the licensee has fully developed this process, we will sample it again during our 2019 inspection.

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

Whilst touring plant areas, we questioned the licensee as to how radiation surveys would be specified to promptly detect any leak/escape of activity from items of unused equipment in the facility?  The licensee explained that it already has a detailed Health Physics (HP) survey schedule in place and that this schedule would be maintained going forward.  In addition there are routine plant walk-downs on a shift basis, which again would be expected to allow prompt detection of any leaks on the plant.  We will sample the HP survey schedules, plant walk-down schedules etc. during our second inspection in 2019.

Conclusion of Intervention

Our overall conclusion, from the evidence sampled during our inspection, was that we have no objection to the implementation of the revised reference safety case and ATO (since ONR extensively sampled the safety arguments during its assessment of PRS2 and the ATO wording clearly reflects the current permitted and limited plant operations).  However, implementation of the new SOE is a ‘work in progress’ and the licensee explained that a series of SOE workshops are still to be held, to define the detail of implementation and to update the Golden Threads as required.  Accordingly, ONR intends to conduct a second inspection in the first Quarter of 2019, to confirm that the licensee’s work on implementation of the SOE is complete and that the SOE can hence be implemented.

Because the inspection rating was ‘Amber’ an ONR Issue will be raised, noting that a further targeted inspection will be conducted, circa first Quarter 2019, to review the licensee’s readiness to implement the SOE.  The expectation at this second inspection would be that the licensee’s implementation processes will have significantly matured in the intervening time.