THE nuclear industry is bidding to relax safety standards to allow the doubling of the number of cracks in the radioactive cores of Scotland’s ageing reactors.

EDF Energy is asking for the safety rules to be rewritten so it can keep running its nuclear power stations at Hunterston in North Ayrshire and Torness in East Lothian until they are at least 47 and 42 years old. They were originally designed to last 30 years.

Prolonged radiation bombardment causes the graphite bricks that make up reactor cores to crack.

EDF is asking the UK government’s watchdog, the Office for Nuclear Regulation (ONR), to permit an increase in the proportion of cracked bricks from 10 to 20 per cent.

The revelation has sparked alarm from politicians and campaigners, who say the industry is “gambling with public safety”. One leading expert argues Hunterston should be immediately shut.

Hunterston started generating electricity in 1976. EDF plans to keep it operating until at least 2023. The ONR is due to conclude a safety review of its future operation at the end of January.

On January 13, EDF closed down one of Hunterston’s two reactors for planned maintenance, including inspections of cracking in the graphite core. It is due to be restarted on February 10.

Torness was started up in 1988 and is currently planned to operate until at least 2030.

The report’s author, Edinburgh anti-nuclear campaigner and consultant Peter Roche, said: “Despite the fact cracks are beginning in the graphite core of these reactors, increasing the risk for us all, the public has not been asked for its opinion.”

Scottish Green MSP for West of Scotland Ross Greer called the lack of public consultation unacceptable.

EDF’s director of nuclear operations Brian Cowell maintains that cracks in more than 1,000 of the 6,000 graphite bricks in a reactor would still give “massive margins of safety where the reactors will still operate safely and shut down safely”.

ONR confirmed EDF’s request and said it would assess it “to see whether we’re satisfied it’s safe to operate”. A spokesman said it would not be appropriate to comment further until its safety review for Hunterston concluded.