Executive summary
Date(s) of inspection:
April 2026
Aim of inspection
This exercise was undertaken by the dutyholder across the Aldermaston AWE Site to test its emergency arrangements and demonstrate compliance with both the requirements of Licence Condition 11 (LC11) and The Radiation (Emergency Preparedness and Public Information) Regulations 2019 (REPPIR).
The evaluation of this exercise also aligns with Key Regulatory Objective 4 of the Office for Nuclear Regulation (ONR) Weapons Sub-Directorate Strategy, which is associated with providing assurance to our stakeholders that activities that may impact upon safety, are planned, and conducted in accordance with the appropriate legislative requirements and that all risks have been reduced to as low as reasonably practicable.
Subject(s) of inspection
- LC11 - Emergency arrangements - Rating: Amber
Key findings, inspector's opinions and reasons for judgement made
AWE Aldermaston conducted its Level 1 site safety demonstration exercise on 15th April 2026. The purpose of this intervention was for ONR to assess the adequacy of AWE’s annual Level 1 safety demonstration against the relevant requirements of LC11, REPPIR and the regulatory expectations provided within ONR’s guidance NS-INSP-GD-011.
A joint Regulators inspection team evaluated the exercise. This team comprised of inspectors from ONR, Defence Nuclear Safety Regulator (DNSR), Defence Nuclear Security Regulator (DNSyR) and the Environment Agency (EA).
It was considered that the scenario provided a high level of challenge to the site's emergency response capability. The inspection team observed a number of elements of good practice throughout the demonstration, for example in regard to effective command and control, maintaining situational awareness and prevention of radioactive waste entering the environment.
The inspection team identified some minor areas for improvement, for example the wearing of Radiological Protection Equipment, initial response by first responders and understanding of radiological risk in the building. Overall, I was content that AWE recognised these improvement points during their own review of exercise performance and during the discussion with Regulators at the end of the exercise.
During the exercise, two shortfalls were identified by the inspection team. The first minor shortfall was seen in the overall control and coordination of Casualty Management. A Level 4 Regulatory Issue will be raised for AWE to produce an improvement plan to address these minor shortfalls in casualty care.
The second shortfall was seen in the Mustering and situational awareness of People at Risk. A Level 3 Regulatory Issue will be raised to address these shortfalls with the requirement to redemonstrate the mustering arrangements afterwards.
Overall, based on the shortfalls seen in Casualty Management and the Mustering arrangements, I judge that an inspection rating of Amber (seek improvement) is appropriate against Licence Condition 11.
Conclusion
Overall, based on the shortfalls seen in Casualty Management and the Mustering arrangements, I judge that an inspection rating of Amber (seek improvement) is appropriate against Licence Condition 11. A Level 4 and Level 3 Regulatory Issue will be raised to address these shortfalls with the requirement to redemonstrate the mustering arrangements in the Level 3 Regulatory Issue.
I have taken these shortfalls through ONR's Enforcement Management Model to decide if any further follow up action is required beyond the Regulatory Issues and concluded that the proportionate enforcement action was to provide Regulatory Advice.
I provided Regulatory Advice in relation to these shortfalls at the end of the inspection which was accepted by the Head of Emergency Planning.