Office for Nuclear Regulation

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AWE Criticality SBI on 13-16 March 2017

Executive summary

Purpose of intervention

The purpose of this intervention was to attend routine briefing meetings with licensee (i.e. AWE plc) personnel to discuss progress with key safety related projects within the two AWE inspection portfolios for which I am the Office for Nuclear Regulation (ONR) Site Inspector.  In addition, together with an ONR specialist criticality safety inspector and a member of the licensee’s own Internal Regulation (IR) team, I conducted a planned Systems Based Inspection (SBI) on the control of criticality safety within AWE’s Main Production Facility at Aldermaston.  This inspection was performed in accordance with the planned inspection programme contained in the AWE Integrated Intervention Strategy (IIS) and associated Intervention Plans.

Interventions Carried Out by ONR

The details of the individual meetings I conducted with key licensee personnel are provided within the body of this Intervention Report.

In addition, accompanied by an ONR specialist criticality safety inspector and a member of the licensee’s IR team, I conducted a planned SBI on the topic of criticality control in AWE’s Main Production Facility at Aldermaston.  Through examination of this system we performed compliance inspections against a number of Licence Conditions (LC). 

Explanation of Judgement if Safety System Not Judged to be Adequate

From the totality of the evidence we sampled during our inspection and from our discussions with key licensee personnel, we are satisfied that the overall marking for the criticality systems based inspection (SBI) is green (see below).

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 immediate regulatory attention.

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

Conduct of the intervention was via examination of licensee documentation and records, discussions with key plant personnel and by inspection of the relevant plant area(s).  The key findings against each LC are recorded below:-

LC 10 – (Training) - Green

The criticality safety training provisions for the Main Production Facility were of an adequate standard, although the licensee has identified that work is required to rewrite/re-design its refresher training for its Movement Controllers.  However, we were satisfied with the licensee proposals for work in this area.  

LC 23 – (Operating Rules) – Green

The licensee demonstrated an adequate criticality assessment process for the derivation of its criticality operating rules (OR) for the facility and we considered these ORs to have been adequately implemented on the plant.

LC 24 – (Operating Instructions) – Green

In our opinion the licensee was able to demonstrate a robust multi-step process for implementation of the safety case derived limits and conditions on the plant.  All documentation we sampled was of an adequate standard and was found to be in order.

LC 27 – (Safety Mechanisms Devices and Circuits - SMDCs) – Green

There are no SMDCs on the plant relating to criticality safety and we were satisfied with the licensee’s explanation as to why this is the case.

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

Whilst we advised the licensee on a number of areas for improvement under this Licence Condition, we did not consider than any such areas merited regulatory action and were satisfied that the licensee is undertaking criticality safety related EMIT maintenance as required by its safety case.

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

We sampled the licensee’s control of potential leakage and adventitious accumulation of material, from its criticality stations, to locations such as ventilation ducting, drains etc.  From the information provided by the licensee we were content that the licensee is adequately meeting its obligations under this Licence Condition.

Conclusion of Intervention

In the case of all the routine meetings I held during March 2017 Inspection Week, in the two inspection portfolios for which I am the ONR Site Inspector, no matters were identified requiring immediate regulatory attention.

From the criticality systems based inspection, conducted in the licensee’s Main Production Facility, a number of areas for improvement were flagged to the licensee but none of these were significant enough to require additional regulatory action.  Accordingly an overall rating.