Office for Nuclear Regulation

Capenhurst Works (UUK) – Inspection ID: 52906

Date(s) of inspection

  • November 2023

Executive summary

Aim of inspection

This inspection was aimed at assessing the licensee’s response to an emergency as required by their emergency arrangements under Licence Condition 11 and their Security Plan. The exercise was the first deployment of an armed response into a nuclear facility and a demonstration of the Capenhurst site claims and reliance on the police armed response team.

Subject(s) of inspection

  • LC11 – Emergency arrangements – Rating: Green

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

Capenhurst undertook a level 1 (site level) emergency exercise on 2nd of November 2023 to demonstrate the site emergency arrangements as required by its site licence under the site Licence Condition 11 ‘Emergency Arrangements’ and the enactment of the site security plan.

The exercise Water Lily scenario incorporated an important security facet with the interception within one of the facility of armed intruders as well as the rescue of a casualty.

The dutyholder’s scenario was realistic and challenging and in addition to the security consideration required the site emergency response to manage and control the chemotoxic and radiological hazards which might have pose a threat to the emergency responders, workers and members of the public.

ONR has observed the exercise in several key locations to assess the ability of the site to manage and maintain the safety and security of the site whilst interfacing with the external emergency responders and demonstrate the capability to respond to the emergency effectively and swiftly.

The declared objectives of exercise Water Lily were achieved and the emergency situation was brought under control in a timely manner with the support of the external emergency services.

ONR identified some areas of good practice and made some observations which will be followed during routine regulatory engagements with the site.

The licensee demonstrated that adequate arrangements are in place as required to comply with the requirements of its site licence condition 11 and its Security Plan, and on the basis of the level 1 exercise observed and the evidence seen this intervention was rated ‘green’.


It is the opinion of the ONR inspectors observing the demonstration exercise that Capenhurst demonstrated with the support and interoperability with Category 1 responders that its emergency response was effective to bring the situation under control adequately in an acceptable timeframe.

The site demonstrated that adequate emergency arrangements are in place as required under Licence Condition 11 and its site security plan, and successfully achieved the declared objectives of the emergency exercise. On this basis this intervention is rated ‘green’.