Office for Nuclear Regulation

Dungeness B – Inspection ID: 52455

Executive summary

Date(s) of inspection:

  • April 2023

Aim of inspection

Observation of the annual level 1 demonstration exercise to confirm that Dungeness B’s emergency arrangements remain effective.

Subject(s) of inspection

  • LC11 – Emergency arrangements – Rating: GREEN

Key findings, inspector’s opinions and reasons for judgement made

ONR observed and assessed the level 1 emergency exercise ‘HARRIER’ at the EDF Energy Nuclear Generation Ltd. (NGL) Dungeness B power station.

The scenario involved multiple casualties as a result of a fire in the Back up Diesel Generator (BUDG) switch house caused by a fault during the racking in/out of an oil circuit breaker.

All of the command centres and intervention staff performed adequately, and overall the licensee successfully:

  • Established three on-site command centres (CCR, ECC and ACP) providing effective command and control. In addition, the corporate CESC was set-up to support the station.
  • Completed a full site muster, accounting for site personnel in a timely manner.
  • Located, assessed and extinguished the fire in the BUDG switch house.
  • Located, assessed, rescued and treated four casualties. (Note, one of the casualties was defined as a fatality in the exercise scenario and a second fatality occurred as a result of the scenario rescue time escalation criteria).
  • Assessed the conditions in the damaged area of the BUDG switch house and implemented appropriate measures to minimise the risk to the intervention team members.
  • Effectively liaised with external agencies and emergency services to support the site response.

We identified shortfalls with the systematic assessment of casualties and the timely deployment of rescue tools and equipment, which will will be managed by level 4 regulatory issues.

ONR were satisfied that the exercise objectives and performance indications in the licensee’s scenario were largely met.


ONR judged that exercise ‘HARRIER’ was an adequate demonstration of Dungeness B’s emergency arrangements and rated the inspection against Licence Condition 11 as Green (no formal action).