Office for Nuclear Regulation

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New reactor licensing


ONR is responsible for licensing companies that wish to construct and operate new nuclear power stations at sites in Great Britain.

A site licence puts the licence holder under strict legal obligations and, importantly, gives wider and deeper regulatory powers to ONR to ensure the safe construction, commissioning and operation of a nuclear site.  The granting of a nuclear site licence is a significant step but is not itself permission to start nuclear-related construction. That requires a separate regulatory permission from ONR.


ONR provides regulatory advice and challenge to organisations intending to apply for a nuclear power station site licence.  We also assesses any subsequent application. 

ONR needs to be satisfied that the applicant's choice of site is suitable; that it understands the hazards and risks of the activities that it proposes to carry out; and that it has a suitable schedule of safety submissions leading through to a pre-construction safety case.  We place particular emphasis on the need to gain confidence that the applicant has the organisational capability to lead and manage for safety effectively.  This means that we must be satisfied with the applicant's governance arrangements, resources, competencies and management processes before can consider recommending that the Chief Inspector grants a licence.

Accordingly, a nuclear site licence for a new nuclear power station is only granted after a rigorous and robust process of assessment.  Licence applicants need to understand ONR's licensing process and expectations and to engage with ONR in an open and transparent way in order to make efficient progress towards obtaining a licence

Current activities

ONR are currently engaging with companies seeking to apply for nuclear site licences at the following sites:

Wylfa Newydd

Horizon Nuclear Power Ltd has submitted its application for a nuclear site licence to construct and operate a Hitachi-GE Advanced Boiling Water Reactor (ABWR) power station at Wylfa on Anglesey.


NuGen Ltd is intending to apply for a nuclear site licence to construct and operate a Westinghouse AP1000 Reactor power station in Cumbria.

Sizewell C

NNB GenCo Ltd is intending to apply for a nuclear site licence to construct and operate a European Pressurised Water Reactor (EPR) power station at Sizewell in Suffolk. At this stage interactions between NNB GenCo and ONR are limited and no additional information on these interactions is provided in these pages.