UK regulators provide update on reactor design assessments

UK regulators expect to complete the Generic Design Assessment (GDA) process for the Westinghouse AP1000 and Hitachi-GE's UK Advanced Boiling Water Reactor (UK ABWR) in March and December of 2017, respectively. In its quarterly GDA report for February to April 2016 issued yesterday, the Office for Nuclear Regulation also said it has "developed 'entry criteria' to provide transparency on the factors that underpin our decision on readiness to commence GDA" for China General Nuclear's HPR1000 design.

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. 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.

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 (SoDA) from the Environment Agency in December 2012. Under a deal agreed last October, China General Nuclear 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.

In its previous update, the ONR highlighted its concerns with progress on the GDA for the AP1000 and "lack of technical convergence" in some topic areas.

The period of the latest report saw some progress, it said, "particularly around convergence and there is therefore only one area where discussions continue". In terms of the closure program, the ONR said Westinghouse had revised and extended its schedule and now seeks to complete the GDA process in March 2017, two months later than planned.

"We have seen an improvement overall in the Westinghouse approach to GDA closure, as a result of its executive-level interventions and revised project governance. However we remain concerned over the volume of work to be delivered, and judge that our planned 'health check' review scheduled for July 2016 will be important in informing the level of confidence we have in the revised closure program," the ONR said.

The UK ABWR project is "in a period of intensive assessment" as it progresses through Step 4 of the GDA process.

"We continue to consider the project stable overall, and although there are technical issues that continue to emerge, they are being appropriately managed," the ONR said. "We remain focused on identifying any further design changes and safety case developments that may be required (in addition to those already made), to enable Hitachi-GE to address them within the current programme timescales."

The Environment Agency is continuing to carry out its assessments and is working towards beginning consultation on its findings so far later this year, according to the report. Natural Resources Wales is also working towards this consultation.

Overall the regulators consider that a DAC and SoDA for the UK ABWR in December 2017 is achievable, the ONR said.

There were no interactions between regulators and the proposed requesting party for the HPR1000 GDA in the period covered by the latest report, ONR noted. But the fact they have developed 'entry criteria' is important, it said, as regulators are required to advise the Department of Energy and Climate Change (DECC) on whether a potential requesting party - in this instance, CGN and EDF - is ready to start GDA.

The report also provided an update on its preparations to assess small modular reactor designs. In March 2016, following conclusion of the techno-economic assessment, DECC announced a competition to identify the best value SMR design for the UK.

"As it is clear that government is progressing work in this area, the regulators have started to think about what challenges technology of this nature may present to the current regulatory regime. We also consider that our knowledge of reactor technology may be helpful to DECC in the design and implementation of the competition, and will provide assistance if requested," the ONR said.

Researched and written
by World Nuclear News