Office for Nuclear Regulation

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AWE - LC19 inspection

Executive summary

Purpose of Intervention

On the 12 and 13 November 2019 the Office for Nuclear Regulation (ONR) undertook an intervention on the Atomic Weapons Establishment (AWE) Burghfield nuclear licensed site to inspect Project Mensa’s compliance with AWE’s arrangements made under Licence Condition (LC) 19 ‘Construction or installation of new plant’ and the Construction (Design and Management) Regulations 2015 (CDM). 

The purpose of the intervention was to inspect AWE’s readiness to safely implement the next phase of construction works (i.e. installation of process, plant and equipment (PP&E)) and inform ONR’s permissioning decision on their commencement.     

Interventions Carried Out by ONR

The scope of this intervention was focussed on Project Mensa from a plant, processes and people perspective and assessed its readiness to safely commence the next phase of works. It comprised desktop-based discussions and a facility inspection and was judged against relevant good practice guidance, specifically:

ONR Technical Inspection Guide (TIG) LC19: Construction or installation of new plant, NS-INSP-GD-019, Revision 5, which provides regulatory expectations for compliance with arrangements licensees are required to make and implement under LC 19 to control the construction or installation of any new plant which may affect safety. (

The Health and Safety Executives CDM guidance.  (

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

N/A – This was not a safety system based inspection.

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

Based on the evidence sampled during this intervention, ONR judged AWE’s implementation of its LC 19 arrangements as ‘Green’ (no formal action required). With respect to ONR’s TIG NS-INSP-GD-019, AWE adequately demonstrated:

ONR judged AWE’s compliance with CDM as ‘Green’ (no formal action required). ONR inspectors were satisfied with AWE’s and the Principal Contractor’s demonstration of how the project was organised and run from a CDM perspective. It was evident there was an open and positive safety culture. A number of examples of good standards were seen during the inspection, in addition to some minor areas of concern where improvements are required. These were summarised during feedback provided at the conclusion of the visit, as were the inspection outcomes/actions required by AWE.

The intervention did identify a number of actions that AWE still has to provide evidence against. In respect of LC 19, these relate to the demonstration of suitable and sufficient backward looking checks as part of the issue of Certificates of Design, and the management of Operation and Maintenance manuals (O&M), including their relationship with the Asset Management System (AMS). In respect of CDM, this includes confirmation that the catenary tower work risk assessment has been reviewed and revised accordingly to include specific details on the location and numbers of inertia reels required for work on the tower, compatibility of the inertia reels with other lanyards and equipment in use, and details of the rescue plan before this work at height recommences.

Conclusion of Intervention

Based on the evidence sampled, ONR judge that AWE’s compliance with its LC 19 arrangements and CDM related to the construction/installation of Project Mensa is adequate in this instance. From the areas inspected, no safety shortfalls were identified that would prevent permission being granted for AWE to commence the next phase of construction works relating to installation of PP&E.