British Energy shares plummeted yesterday after the firm said repairs would force it to reduce electricity production.
Stock prices slid 8.3 per cent in London after the firm said maintenance and inspections at its nuclear reactors would cut output by two terawatt hours, equivalent to about 3.2 per cent of production for the current fiscal year.
Shares fell 52.5p to 582.5p, handing the utility a value of £3.32 billion.
The Scotland-based firm said it was confident of meeting its power-production target of 61 to 63 terawatt-hours for the financial year ending in March 2007, even with the new maintenance at its Hinkley Point B reactor 3.
The firm said it may have to stop the number four reactors at Hinkley point B and Hunterston B for inspections and repairs because of boil-tube cracking.
The government owns about two-thirds of British Energy through the Nuclear Liabilities Fund.
British Energy runs eight nuclear power stations in Britain.