Office for Nuclear Regulation

AWE - SBI - ATC Fire Protection System

Executive summary

Purpose of Intervention

The Office for Nuclear Regulation (ONR) undertakes all regulatory interaction with the Burghfield site licensee (AWE plc) against a strategy defined by the ONR Weapons sub-Division. In accordance with that strategy, a System Based Inspection (SBI) was carried out on the Assembly Technology Centre (ATC), as planned, in February 2019. 

The purpose of this inspection was for the ONR to determine the adequacy of implementation of those safety claims related to the system being inspected.  As part of the SBI methodology, adequacy of implementation against five pre-defined Licence Conditions (LC) was also considered.

Interventions Carried Out by ONR

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

I led a System Based Inspection of the Fire Protection system, which is installed within a number of facility areas in the ATC.  As part of that inspection, I also made judgements as to the adequacy of compliance against five Licence Conditions; LC 10 (training), LC 23 (operating rules), LC 24 (operating instructions), LC 27 (safety mechanisms), and LC 28 (examination, inspection, maintenance and testing).  

Explanation of Judgement if Safety System Not Judged to be Adequate

During the inspection, I observed evidence of shortfalls against the condition of some components and structures which form part of the fire barrier boundary, due to an insufficient scope in the related maintenance.  Although there was also some evidence of adequate compliance, the engineered shortfalls underpin my judgement that the licensee has not demonstrated that the system has adequately implemented all safety related claims.   

However, I consider that these shortfalls can be addressed within a reasonable timeframe, and I will track the delivery of those related commitments that have been made by the licensee.  On the basis that the licensee can recover to a position of sustained compliance within an acceptable timeframe, I consider that facility operations can continue without additional temporary constraint.  

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

From the evidence examined during this inspection, I consider that AWE has not adequately implemented some of those claims within the facility safety case that I sampled; in particular shortfalls related to a number of elements within one of the key facility fire barriers.

Additionally there were observed shortfalls in the licensee’s ability to identify all the relevant operational limits and conditions to the relevant operational staff, which could hamper their delivery by personnel on plant.

Based on the sampled evidence, I consider that a rating of Green (no formal action) is merited for Licence Conditions 10 and 24.  For Licence Conditions 23, 27 and 28, I consider that a rating of Amber (seek improvement) is merited, as the currently installed condition of some of the system components was not to the standard I, or the licensee, would expect.

In my opinion, the shortfalls observed during this inspection can be addressed within a reasonable timescale, and I consider that the licensee has the ability to return to a position of sustained compliance.  Therefore, I consider that the proportionate regulatory response is to raise a number of ONR Regulatory Issues to track the resolution of these shortfalls, and to seek such resolution within an agreed timeframe.

Conclusion of Intervention

I consider that the licensee’s formal arrangements for compliance with Licence Conditions 10 and 24 are being implemented adequately, but that shortfalls in compliance have been identified against Licence Conditions 23, 27 and 28.  

Therefore, on the basis of the evidence sampled within this inspection, I judge that the licensee has not adequately implemented all of the claims within its safety case.  However, provided that the licensee addresses these shortfalls within a reasonable timeframe, I judge that operations can continue without additional temporary constraint.

Therefore, I will raise four ONR Regulatory Issues to ensure that AWE addresses the identified shortfalls within an agreed timeframe.