Hitachi-GE and Westinghouse set for GDA completion

UK regulators expect to complete the Generic Design Assessment (GDA) of the AP1000 and the UK Advanced Boiling Water Reactor (UK ABWR) in March and December this year, respectively. They have also reported the start of the GDA of the UK HPR1000, which they expect to complete in 2021.

In their latest periodic report assessing new nuclear reactor designs, covering the period November 2016 to January 2017, the Office for Nuclear Regulation (ONR), the Environment Agency and Natural Resources Wales, have provided an update on work they have been carrying out on their GDA of the Westinghouse and Hitachi-GE reactor designs, as well as the start of a GDA for General Nuclear System's UK HPR1000.

Horizon Nuclear Power - established in 2009 and acquired by Hitachi in November 2012 - 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.

NuGeneration (NuGen), the UK joint venture between Japan's Toshiba and France's Engie, plans to build a nuclear power plant of up to 3.8 GWe gross capacity at Moorside, in West Cumbria using AP1000 nuclear reactor technology provided by Westinghouse Electric Company, a group company of Toshiba.

The UK EPR design became the first reactor design to complete the GDA process and receive a Design Acceptance Confirmation (DAC) from the ONR and a Statement of Design Acceptability from the Environment Agency in December 2012. Under a deal agreed in October 2015, China General Nuclear (CGN) will take a 33.5% stake in EDF Energy's £18 billion ($28 billion) project to construct Hinkley Point C, in Somerset, which will comprise two Areva EPR units. In addition, the two companies will develop projects to build new plants at Sizewell in Suffolk and Bradwell in Essex, the latter using Chinese reactor technology - the HPR1000. General Nuclear Systems is a joint venture between CGN and EDF, developed to deliver the Bradwell project in Essex.

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.

UK ABWR

During the period, the ONR "continued the step 4 detailed assessments and moved towards ensuring technical convergence and beginning to finalise assessment requirements as the project moves into its final year".

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. This is a further indication, it says, 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 DAC and SoDA in December.

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 said. "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. In addition, at this stage we do not anticipate new significant technical matters to be identified by our assessments, although we cannot preclude it, and we consider that overall the project is stable."

In terms of the fuel export design, the ONR sought independent technical advice on the extant design and 'optioneering' and as low as reasonably practicable (ALARP) analysis provided by Hitachi-GE.

"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. For PSA, progress has been made and we have been able to close some aspects of the RI actions and supporting ROs," the report said.

AP1000

There has been a "significant increase in pace, progress and delivery" in the period for the AP1000 GDA. For example, Westinghouse provided 163 formal submissions that represent about 20% of its total submissions for the GDA closure phase.

"We have reported the compression of the program 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. 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. 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," the report said.

ONR and Westinghouse have also provided "enhanced management attention on critical path topic areas", it added, and implemented weekly management progress updates across the teams, all with a view of enabling Westinghouse to complete the GDA successfully on time.

This increase in pace and delivery has "dramatically improved" the Westinghouse position and increased the likelihood of the project completing on time at the end of this month, it said.

"As we signalled in our last update, ONR undertook a project wide health check/deep dive in January 2017. 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," it said.

In the area of structural integrity there is still technical work outstanding, however. "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," the report said.

HPR1000

The regulators received a request from the government to commence a GDA of the UK HPR1000 reactor technology on 10 January. This followed work by the regulators and General Nuclear System (GNS), the requesting party acting for China General Nuclear and EDF, on the pre-requisites for GDA.

"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 UK HPR1000 GDA formally started on 19 January 2017," the report said.

Following completion of the GDA, which is expected in 2021, it is proposed that UK HPR1000 reactors will be deployed at the Bradwell B site in Essex.

The regulators have "mobilised a team" and begun preparatory work for a technical workshop in China this month.

Researched and written
by World Nuclear News