Executive summary
Date(s) of inspection:
- March 2026
Aim of inspection
This inspection was undertaken across the AWE Explosives Business Unit (XBU) and aligned with the Office for Nuclear Regulation (ONR) 2025/26 integrated intervention strategy for theweapons sub-directorate.
This intervention was associated with Theme 1 of the XBU sub-strategy, Improved Safety Performance and supported the following key regulatory objectives (KRO) and desired regulatory outcomes (DRO):
- KRO.2 -AWE Plc continues to demonstrate safe delivery of current operations and existing facility upgrades.
- DRO.2.10 - AWE Plc to demonstrate fit for purpose arrangements and governance structure to support modifications to existing facilities.
- DRO.3.3 - ONR to undertake Risk-Informed and Targeted Engagements (RITE) acrossrelevant statutory provisions(RSPs) of HSWA during construction and demolition activities.
The main focus of the inspection was to assess the adequacy of the arrangements associated with modifications, and that they were being appropriately implemented to ensure compliance with RSPs of the Health and Safety at Work etc Act 1974 (principally Electricity at Work Regulations 1989).
Subject(s) of inspection
- Health & Safety at Work Act - Rating: GREEN
- LC 22 - Modification or experiment on existing plant - Rating: GREEN
Key findings, inspector's opinions and reasons for judgement made
The ONR inspection team attended the XBU, which is located on the AWE Aldermaston nuclear licensed site on 24 March 2026 to undertake this inspection sampling the control of modifications to existing facilities and site compliance with the Electricity at Work Regulations 1989. The inspection team comprised an electrical engineering specialist inspector and the site inspector.
A number of documents were requested in advance of the inspection and these were received in a timely manner and were sampled as part of preparation activities. The inspection followed a high-level scope that had been proposed by ONR and shared with XBU in advance of the inspection.
The inspection targeted aspects of Licence Condition 22 and Electricity at Work Regulations 1989 compliance and sampled the adequacy of high-level and local arrangements and their implementation across a specific facility undergoing an upgrade programme.
Elements of good practice were identified as part of the inspection. For example, in regard to the governance arrangements of non-standard electrical isolations and how these are controlled at the point of work.
Observations were raised and shared with the dutyholder as advice and guidance relating to the following areas:
-
improving clarity with respect to the hazards posed by working with electricity detailed in the risk assessment forming part of a safe system of work
- improving clarity on the traceability of a risk assessment used in justifying a design decision for the installing temporary electrical equipment into a facility
The observations raised were judged to represent minor shortfalls. It was agreed that these could be addressed by the dutyholder as part of its normal business. Therefore, I rate the inspection as adequateGREEN(No formal action).
This rating is in line with the established ONR guidance as follows:
- relevant good practice generally met, or minor shortfalls identified, when compared with appropriate benchmarks
- no significant shortfalls identified in the delivery of safety, safeguards or security function
Conclusion
Compliance with LC22
The dutyholder demonstrated effective arrangements for managing modifications. Documentation was reviewed and found to be suitable, with evidence of appropriate authorisation and risk assessment. Staff demonstrated awareness of the requirements, with clear traceability for all changes made to plant and equipment.
I judge from the sample taken and discussions held during this inspection, that AWE’s arrangements comply with the expectations of LC22. Therefore a Green (no formal action) rating was given.
Compliance with Electricity at Work Regulations
Electrical safety procedures were observed to be suitable and sufficient, with regular inspections and maintenance schedules in place. Testing records for electrical installations were available and current. The competency of staff carrying out installation and maintenance activities was controlled by letters of appointment reviewed at regular intervals. There was good practice demonstrated for non-standard electrical isolations and the associated governance arrangements.
The decision making process and controls sampled for live electrical working aligned to RGP and appeared suitable and sufficient to mitigate the risks posed. One observation was raised with respect to the limited detail contained in the risk assessment for the installation of temporary electrical supplies, however in my judgement this did not represent a significant shortfall or risk as the connection for the installation was yet to have been made. This was followed up by the facility inspector.
I judge from the work activities sampled and discussions held during this inspection, that AWEs arrangements comply with the expectations of EAWR89. Therefore a Green (no formal action) rating was given.Overall, from the samples taken, the inspection concluded that the site demonstrated compliance with LC22 and the Electricity at Work Regulations, with minor Observations identified and shared with the dutyholder as advice and guidance to further enhance safety and support continued compliance. Therefore an overall rating of Green (no formal action) was given for this inspection.