IMMINENT cracking in the Hunterston nuclear station will affect its ability to operate safely, the Nuclear Installations Inspectorate has warned.
Its assessment of the Ayrshire plant and its twin, the Hinkley Point station, raised concerns about the safe running of Britain's ageing nuclear reactors.
Just one of British Energy's eight nuclear stations was fully operational last week.
"The majority of fuel moderator bricks will develop a single through-thickness crack," the inspectorate's report said.
Further cracks could split the bricks in half.
"Brick cracking could affect the ability of the graphite core to meet its safety requirements," it added.
It could take up to six months to fix existing cracks in the boiler tubes at Hinkley, which were disclosed last week by British Energy.
Both stations, which provide 6 per cent of Britain's electricity, have been closed, but the industry and the government want their 30-year lifespans extended by a decade.
They account for around a fifth of British Energy's income, or 2 million a week.
The company said the problem was "solvable".