Horizon Nuclear Power announced on 4 April that it has submitted its site application to the UK Office for Nuclear Regulation (ONR) to build and operate two Advanced-Boiling Water Reactor (ABWR) units at the Wylfa Newydd NPP on the island of Anglesey. A rigorous 19-month programme of assessment will now begin to establish whether Horizon can demonstrate its control of all safety related activities on its site. The application follows more than two years of preparation by Horizon and focuses on the suitability of the organisation, the site and the reactor design, Horizon said in a statement.

ONR said it will now review the application, "carrying out robust assessments of the applicant's organisation capability, governance arrangements and competence to be a nuclear site-licence holder". It will also assess the adequacy of Horizon's technical safety plans. The site licence will be granted after Horizon has met 36 licence conditions and licensee obligations.  Horizon would then be regulated by ONR for the full lifecycle of the site from construction to decommissioning. Horizon is now preparing to undertake its final stage of community consultation in the summer. Hitachi-GE’s UK ABWR reactor technology is progressing through the fourth and final stage of its generic design assessment, and is on track to be approved for use in the UK by the end of December 2017. If that approval is granted, Horizon aims to receive all the necessary permissions by the end of 2018.

Horizon plans to build at least 5,400MWe of new nuclear power generation capacity at the Wylfa Newydd and Oldbury-on-Severn NPPs. Its power station sites will employ 850 people each once operational with a construction workforce of between 8,000 and 10,000. Horizon Nuclear Power Wylfa Ltd, the Horizon group company that submitted the site licence application, is a separate legal entity that, if granted a nuclear site licence, will be the Site Licence Company responsible for the construction and operation of Wylfa Newydd.