Three out of 6,000 bricks in the graphite core were found to be cracked, which was predicted to start happening at this point in the station's life, the company said.

"It does not affect the operation of the reactor and the findings have no safety implications and are well within any limits for safe operation," it said in a statement.

It added that inspections on other stations found similar results in October 2014. Further inspections will look at more of the Hunterston B graphite core and any additional cracks will be reported, it said.

Last year, two of EDF Energy's nuclear power plants in Britain - Heysham 1 and Hartlepool - were offline for inspections for months after a crack was found on a boiler spine at Heysham 1.

(Reporting by Oleg Vukmanovic in Milan; Editing by Susan Fenton)