Wylfa Newydd Nuclear Power Station

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Wylfa Newydd Nuclear Power Station

Received 09 August 2018
From Office for Nuclear Regulation


The Office for Nuclear Regulation (ONR) is the principal regulator of the safety and civil nuclear security of the UK nuclear industry. ONR licenses and regulates a broad range of nuclear facilities and activities, and is also responsible for nuclear safeguards and the regulation of transport of radioactive materials.
In March 2017, Horizon Nuclear Power Wylfa Limited (Horizon) applied for a nuclear site licence to allow it to install and operate two UK Advanced Boiling Water Reactor (ABWR) reactors at its Wylfa Newydd site; this application is currently being assessed by ONR. The standard nuclear site licence comes with 36 licence conditions and ONR will not grant a licence to Horizon until it is satisfied that the company has adequate, fit-for-purpose arrangements that address all of these licence conditions.
The grant of a nuclear site licence will not give Horizon permission to proceed with nuclear-related construction on the site. The licence conditions allow ONR to exercise a number of controls throughout the construction or installation, commissioning and operation of the station. In particular, commencement of nuclear related construction on the site, which ONR defines as the placement of the first structural concrete for buildings with nuclear safety significance, will require a separate permission by ONR granted under one of the licence conditions. ONR may also elect to permission other stages of construction or installation and commissioning.
The proposed twin reactor development at Wylfa Newydd is based on the Hitachi-GE Nuclear Energy, Ltd. UK ABWR nuclear reactor design. ONR has completed a Generic Design Assessment (GDA) of this design which led to the granting of a Design Acceptance Confirmation (DAC) in December 2017. Provision of a DAC means that in ONR’s opinion, on a site bounded by the generic site envelope, the generic reactor design could be built and operated in Great Britain, in a way that is acceptably safe and secure (subject to site specific assessment and licensing). The DAC explains that it does not guarantee that ONR will grant permission for the construction of a power station based on the UK ABWR nuclear reactor design at a particular site in Great Britain. That permission will be informed by a site specific pre-construction safety case after a nuclear site licence is granted. ONR also notes that some safety case work is required before a nuclear site licence is granted. For example, focussing on areas not bounded by the DAC.

ONR’s licensing work will also take into account the adjacent Magnox Wylfa site
ONR has examined relevant parts of Horizon’s Wylfa Newydd Development Consent Order (DCO) application and its supporting documents. At this stage we have no substantive comments. However, we will provide a more substantive representation at the start of the DCO examination phase which will highlight any issues which arise from our further examination of the DCO application, as well as providing a more detailed progress report on our work on assessing Horizon’s application for a nuclear site licence.
In addition, ONR will be pleased to provide advice or evidence to the Examining Authority regarding matters identified as relevant in the Nuclear National Policy Statement as well as on any issues relating to our regulatory role or processes which may arise during the Examining Authority’s consideration of the DCO application.