Executive summary
Date(s) of inspection:
April 2026
Aim of inspection
The aim of the inspection was to determine the adequacy of the licensee's arrangements for dealing with any accident or emergency arising on the site and their effects.
Subject(s) of inspection
- LC11 - Emergency arrangements - Rating: Amber
Key findings, inspector's opinions and reasons for judgement made
ONR assessed the level 1 emergency exercise ‘MAVEN’ at the EDF Energy Nuclear Generation Ltd Dungeness B power station.
The exercise scenario involved an out of hours response to a fault in the irradiated fuel disposal facility (IFD) resulting in a dropped fuel assembly and a subsequent release of contamination and carbon dioxide. Additional challenge was introduced by a fire in the turbine hall initiated by a failure of the extreme low level insurge (ELLI) pump motor. The scenario included three casualties, one from the fire and two in the IFD, with an additional person failing to muster.
The licensee's response broadly met the exercise objectives and adequately achieved the following key outcomes:
- Prompt activation of the emergency arrangements
- Completion of a full site muster, accounting for all persons within an adequate time-frame
- Timely deployment of IRT and fire team
- Effective control of Carbon Dioxide and radiological hazards
- Effective information flow between command centres
The performance of the on-site command centres was judged to be adequate, however we observed shortfalls associated with:
- Welfare of emergency response staff
- Medical treatment of casualties
- Capacity to manage multiple casualties
- Capability / availability of additional first aid resource
- Contamination control
- Decision making and incident scene management
Conclusion
We were satisfied that the exercise scenario provided an appropriate level of challenge to demonstrate the implementation of the emergency arrangements at Dungeness B.
We judged that the licensee’s performance was not adequate and rated the inspection AMBER (seek improvement) against licence condition 11 (emergency arrangements).
The ONR enforcement management model has been applied to determine the appropriate enforcement action.