UK GDA reports good progress for AP1000 and UK ABWR

23 March 2017

In their latest quarterly report on the Generic Design Assessment (GDA) of new nuclear reactor designs, the UK’s Office for Nuclear Regulation (ONR), Environment Agency, and Natural Resources Wales, offer updates on their GDA of the Westinghouse AP1000 and Hitachi-GE’s UK Advanced Boiling Water Reactor (UK ABWR). The report, for November 2016 to January 2017, also considers the start of the GDA of the UK HPR1000.


There has clearly been an immense effort to move the Westinghouse project forward. NuGeneration (NuGen), a UK joint venture between Japan's Toshiba (parent company of Westinghouse) and France's Engie, plans to build two AP1000 units at Moorside, in West Cumbria. However, there is some uncertainty over this project now, given Toshiba’s current financial difficulties (see related story).

The regulators report "significant increase in pace, progress and delivery" for the AP1000 GDA, noting that Westinghouse provided 163 formal submissions representing about 20% of its total submissions for the GDA closure phase. “The ONR team has maintained pace and undertaken an extensive amount of assessment in this short period of time to enable Westinghouse to complete the GDA in March 2017,” the report says. However, it adds: "We have reported the compression of the programme for this project in earlier reports, and although Westinghouse has been able to meet its schedule, the back-end loading of work has placed considerable pressure on ONR resources…. To support this accelerated pace the level of communication and interaction between the Westinghouse and regulatory teams has also increased at all levels within the project."

ONR and Westinghouse have also provided "enhanced management attention on critical path topic areas", it adds, implementing weekly management progress with a view of enabling Westinghouse to complete the GDA successfully on time. This has "dramatically improved" the Westinghouse position and increased the likelihood of the project completing on time at the end of this month, the report says. “We have improved our delivery confidence from amber/red to amber/green as a key outcome from that review. The sheer volume of work undertaken by ONR in this period has contributed to this change in position." 

However, there is still technical work outstanding on structural integrity. "This therefore remains a project risk although we are confident of a way forward. There have been other technical hurdles within the period, but for the majority of areas ONR has been able to work expediently with Westinghouse to resolve them."


As to the UK-ABWR, Hitachi-GE has now submitted over 90% of its GDA 'deliverables' and those remaining relate largely to the Pre-Construction Safety Report (PCSR), according to the report, which says this is a further indication that the project is completing the assessment phase. The regulators expect to conclude detailed technical work in the summer and move into drafting the step 4 reports that will underpin a decision on whether to grant a Design Acceptance Confirmation (DAC) and Statement of Design Acceptability (SoDA) in December.

Horizon Nuclear Power plans to deploy the UK ABWR at two sites - Wylfa Newydd, which is on the Isle of Anglesey, and Oldbury-on-Severn, in South Gloucestershire. Horizon was established in 2009 and acquired by Hitachi in November 2012.

The Environment Agency and Natural Resources Wales began a 12-week public consultation in December, which sought views on the environment agencies' preliminary conclusions following detailed assessment of the UK ABWR design, and on the environmental aspects of the design. Their consultation ended on 3 March.

"There have been no new, significant technical issues emerging in this period," the report says. "We have concluded work on the fuel export design as reported in our last progress update and progressed assessment relating to the one outstanding Regulatory Issue in Probabilistic Safety Analysis. Furthermore, we expect a significant number of Regulatory Observations (ROs) to be closed in the coming period. For these reasons, we have moved the delivery confidence for the project from amber/green to green; reflecting regulatory confidence in the likely success of the project concluding in December 2017.” The regulators do not anticipate new significant technical matters to be identified, “although we cannot preclude it”, and consider that overall the project is “stable”.

"Our final conclusion is that Hitachi-GE has made a robust case for the current design and its optioneering work is commendable. There are some residual matters around managing the risk of foreclosing future design options, which we will take forward with Hitachi-GE.” 


The UK HPR1000 GDA formally started on 19 January 2017 following a UK government request. This followed work by the regulators and General Nuclear System (GNS), which is acting for China General Nuclear (CGN) and EDF, on the pre-requisites for GDA. The GDA is expected to be completed in 2021, after which UK HPR1000 reactors may be deployed at the Bradwell B site in Essex. 

"The regulators confirmed to the Department for Business, Energy and Industry that GNS were in a good position to commence the GDA and there is confidence that they have the capability and capacity to complete the process in a reasonable timeframe," the report says. The regulators have "mobilised a team" and begun preparatory work for a technical workshop in China this month.

EDF and CGN have already seen the GDA process completed for the UK EPRs planned for Hinkley Point C.  The reactor has received a DAC from ONR and a SoDA from the Environment Agency in December 2012. According to the report, the ONR will "realign" its regulation of new nuclear build from April, to be "technology facing rather than lifecycle based (GDA, licensing, construction)", and will provide more information on this in future updates of its work.

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