EDF Energy has announced that two reactors at Scottish power plant Hunterston B plant will remain offline for an extended period, after cracks were discovered last year.
Hunterston B has been offline for more than 12 months and EDF Energy has confirmed that it will remain offline for another month while safety inspections continue.
The deadlines to restart the reactors was scheduled for the end of June, and has now been pushed back to 31 July.
The two nuclear reactors at the North Ayrshire plant were shut down for detailed inspections following the discovery of cracks in the graphite bricks used in the reactor cores.
Hunterston B crack
Source: EDF Energy
EDF Energy has stressed that the cracks, which measure 2mm across, are within acceptable limits and are “a known phenomenon” for the type of reactor technology given its age and do not pose a safety risk. Cracks under 10mm are considered acceptable under EDF’s internal regulations.
However, to restart the reactors EDF Energy will need to complete safety cases to be reviewed and approved by the Office of Nuclear Regualtion (ONR).
EDF station director Colin Weir said: “Following the core inspections and extensive modelling, the safety case providing the justification for return to service of Reactor 4 has been provided to ONR for their assessment.
“The ONR will, completely independently, review the case before deciding whether or not to approve for return to service. It is not possible for us to confirm with certainty how long this process will take; our top priority is that it’s completed with appropriate rigour. The safety case for Reactor 3 is still to be submitted to ONR.”
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