Regulators in the United Kingdom have issued interim design approval for both the Areva EPR and the Westinghouse AP1000 reactors. A number of technical issues still need to be clarified before either reactor can be built in the UK, but the regulators are satisfied with the vendors’ plans to resolve them.

For both designs, the Office for Nuclear Regulation has issued interim Design Acceptance Confirmations (iDAC) and the Environment Agency has issued interim Statements of Design Acceptability (iSoDA). The move follows a detailed four-year review of the designs, involving over 60 staff.

“We have reached an important milestone, said Kevin Allars, Office for Nuclear Regulation director for nuclear new build.

“This interim acceptance confirms that all the plans on how the industry will resolve the outstanding issues are in place.” This includes plans to resolve any new issues identified as a result of the lessons learned from Fukushima.

In the meantime, the regulator has listed all the 51 outstanding issues for the Westinghouse AP1000, and the 31 issues for the Areva/EDF EPR reactor.

Although both reactors made it through the process thus far, they each have different circumstances. Areva/EDF are now working to close out EPR reactor issues, and have begun pre-preliminary site work at Hinkley Point in Somerset. Westinghouse has suspended all work until a UK utility customer decides in its favour.

At a supply chain event in London in mid-December, EDF announced the consortium of Kier BAM as preferred bidder for the GBP 100 million site preparation works at Hinkley Point. It and partner Centrica also announced a deal with Areva to start work on main reactor systems in January.

Under UK legislation, all of the costs of the regulatory process are billed to vendors.

So far, the process has cost Areva/EDF GBP 25 million, and Westinghouse GBP 24 million. Allars said that Areva/EDF has increased its operating budget to 31 million; the Westinghouse budget is now frozen, Allars said.

He said that instrumentation and control issues loom large for both vendors. The issue was so serious for the EPR design that the vendor had to agree to supply an additional system—a non-computer hardwired back-up—in order to satisfy regulators’ concerns that the safety system was sufficiently diverse to the operations system. Allars said that the regulator is still waiting for many of the details of how this system will work.

Both vendors also have to consider how resistant the design might be to large natural disasters, such as the tsunami that caused catastrophic damage at the Fukushima Daiichi plant in Japan.

The AP1000 design, which has been revised several times in the USA, is also likely to be approved by its national regulator (NRC) late in 2011 or early in 2012. Allars said that, allowing for a different UK and US regulatory process, the two were ‘pretty aligned.’

In a statement, Areva and EDF said that they were ‘committed’ to resolving the issues.

Chairman of Areva UK, Alain-Pierre Raynaud, said: “After four years of the most detailed and careful examination of the EPR design by the UK regulators, they have concluded that they are largely satisfied with both the design and the safety case of the EPR.”

Vincent de Rivaz, the head of EDF Energy, which is planning to build four EPRs in the UK, described the announcement as “very good news for the EPR and for UK new nuclear build.”

Meanwhile, Westinghouse has announced a memorandum of understanding (MOU) with DBD Limited relating to the future development of the AP1000 reactor design in the UK. The agreement covers support through the final stages of the Generic Design Assessment process, site-specific licensing, planning support and associated safety-case development.

Westinghouse Vice President for the UK, Middle East & Egypt, Mike Tynan, commented: “As we progress towards Interim GDA approvals and hopefully then towards selection of our design by a UK utility, we are working to identify and build connections to those companies who are best placed to support the next phase of our UK journey.”

FilesReactor-by-reactor Fukushima Daiichi restoration progress summary as of 15 December, from JAIF