Safety threat to planned nuclear power stations

Britain's plans to build a new generation of nuclear power stations have been thrown into jeopardy by startling official safety fears. The nuclear regulatory body in Finland, where the first of the reactors is being built, has taken the extraordinary step of threatening to halt its construction because it has not been satisfied that key safety systems will work.

STUK, the Finnish government's Radiation and Nuclear Safety Authority, says that "evident errors" have not been corrected more than a year after it raised its concerns and condemns the "lack of professional knowledge" of people working for the firm responsible for its design and construction.

This is an unexpected, and potentially devastating, blow because one of the main selling points of the new European Pressurised Reactor (EPR) has been that its safety systems will work far better than those in current reactors. It is particularly important that they do because, as The Independent on Sunday reported in February, they will produce many times as much radiation that could be rapidly released in the event of an accident.

EDF, the French electricity generator, plans to build at least four EPRs in Britain; two each are expected for existing nuclear sites at Sizewell in Suffolk and Hinkley Point in Somerset. It plans to let the first construction contracts this year and to have the first power station in operation by 2017. However, the first EPR, called Olkiluoto 3 – which is being built on an island in the Gulf of Bothnia, off western Finland – has already been plagued with problems. It was supposed to begin operating this year but its construction is now three years behind schedule, vastly exceeding its original cost of €3bn.

The new crisis has been sparked by a leaked letter from Jukka Laaksonen, STUK's director general, to Anne Lauvergeon, the chief executive officer of the French nuclear company Areva, which has designed and is building the reactor, to express his "great concern" over "the design of the control and protection systems".

He said he first raised the issue in the spring of 2008, but "we have not seen expected progress in the work on the Areva side" adding that "the attitude or lack of professional knowledge" of some of the people representing the firm in expert meetings on the issue "prevents progress in resolving the concerns. Therefore evident design errors are not corrected and we are not receiving design documentation with adequate information." He warns: "Without a proper design that meets the basic principles of nuclear safety... I see no possibility of approving these important systems for installation. This would mean that the construction will come to a halt."

John Large, an independent nuclear consultant, describes the warning as "a hell of a damp towel for the reactor", and says that STUK's ultimatum shows that "it must consider the safety issue very serious indeed". The Health and Safety Executive, which will have to approve the EPR for use in Britain, is already liaising closely with STUK.

The letter was written last December, but a spokesman for STUK said late last week that, as far as he was aware, the situation had not changed since. Areva said it had sent some more files to the Finnish utility that will operate the power station, but admitted that "there are still some problems to solve".

EDF declined to comment.