British Energy, the UK’s largest electricity generator, yesterday confirmed that two of its nuclear reactors would remain shut for the foreseeable future.

The plants were closed last month when the company discovered a corroded steel wire in the concrete casing of one of two reactors at its Hartlepool power station, which supplies 1.5 million homes with electricity.

British Energy said that it had discovered a similar problem at its Heysham 1 reactor, confirming fears that the problem was not an isolated one and would require further inspections, remedial work and many more months of closures to fix.

News that the reactors are unlikely to be back on line quickly will put pressure on gas prices, because the UK will have to import more gas to meet winter peak demand.

It also underlines the problems of Britain’s ageing nuclear stations at a time when the consultation on whether to build a new generation of nuclear stations is nearing a conclusion.

British Energy is trying to position itself as the nuclear operator of first choice for any next generation of reactors. However, repeated operational problems, which the company has blamed on decades of underinvestment, have caused some to question whether it should be allowed to be involved in building new reactors.

The company, which is to report half-year results next week, was unable to say how long the inspections would take, but analysts believe that the plants are likely to be shut down until March at the earliest.

Peter Atherton, an analyst for Citigroup, said: “This is bad news for British Energy. In our view, it now looks increasingly likely that the reactors will be down for the rest of winter.”

British Energy called the problems a “legacy issue” and said that they had been discovered during a routine inspection. It said: “This is a complex issue and a timetable for the return to service of these units can only be formed when inspections and a full assessment of the situation have been completed,” The company said that it would provide a description of the issue and how it was being addressed as part of its results presentation next week.

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