UK regulator raises French nuclear concerns

French plans to lead a nuclear power renaissance in Britain have been dealt a major blow after regulators warned of serious reservations about the safety of the reactor technology earmarked for use.

The Nuclear Installations Inspectorate (NII) has written to EDF and Areva, the French companies that want to build four reactors in the UK, to express their concerns about the technology. The letter sets out concerns about the control and instrumentation (C&I) of Areva's European Pressurised Reactor (EPR).

Described by one nuclear industry source as the "cerebral cortex" of a nuclear power station, C&I governs the computers and systems that monitor and control the station's performance, including temperature, pressure and power output levels.

The NII, which is conducting a detailed review of two reactor designs for the UK, said the EPR technology was significantly compromised because of the interconnectivity of what were meant to be independent systems designed to operate the plant and ensure its safety.

The Health and Safety Executive, which oversees the NII, said that the EPR design could be rejected for use in Britain if its concerns could not be satisfactorily addressed. "It is our regulatory judgment that the C&I architecture appears overly complex," the NII letter said. "We have serious concerns about your proposal which allows lower safety class systems to have write access [the ability to override] to higher safety class systems," it continued.

The letter also highlighted concerns about the absence of safety display systems or manual controls that would allow the reactor to be shut down, either in the station's control room or at an emergency remote shutdown station.

The NII's warning will compound the view that EDF, the utility giant that is 85 per cent owned by the French state, is unlikely to meet its target of building its first UK reactor within eight years.

Areva is already scrambling to produce revised plans but the design assessment phase could be delayed well past its expected completion in 2011.

EDF wants to build four reactors in Britain at two sites, Hinkley Point in Somerset and Sizewell in Suffolk. Last year it spent more than £12 billion acquiring British Energy, the UK nuclear generator, to secure access to them.

The French-designed EPR is the world's most powerful nuclear reactor. Each is capable of generating 1,600 megawatts of electricity - enough to supply a city of nearly 2 million people.

While two EPRs are being built in Finland and France, none is yet in service. The prototype EPR, at Olkiluoto in western Finland, is running three years late and billions of euros over budget.

The NII said that it would grant a licence for the EPR reactor only if it was satisfied that the reactor design could be built and operated safely and securely.

Finnish regulators raised earlier concerns about the reactor's C&I systems but this is the first time that their British counterparts have done so.

Areva and EDF are in talks with the NII about a revised design. Areva said: "The group is committed to ensuring the safety of the EPR reactor and to meeting the UK's specific requirements. The group is confident that a solution can be defined in the months to come."

EDF said safety was the company's No 1 priority at all times.