350 cracks in core of nuclear reactor
...but operator EDF is keen to power it up again
MORE than 350 cracks have been found in a reactor at a Scottish nuclear power station.
Reactor Three at Hunterston B in Ayrshire was taken offline in March after hairline cracks were discovered in granite bricks at its core.
The damage, caused by the fission process, meant the reactor no longer met strict safety standards set down by the Office for Nuclear Regulation (ONR).
A smaller number of cracks were already known about but the total has risen sharply following a series of inspections carried out since March.
Despite this, plant owner EDF Energy plans to bring the reactor back online, saying the cracks leave the power station’s day-to-day operations ‘unaffected’.
The ONR confirmed that the number of cracks exceed the reactor’s ‘operational limit’ but said they posed no immediate safety risk.
Reactor Three originally started generating electricity in 1976, and is the oldest in the UK run by EDF.
Taking it offline resulted in the output of Hunterston falling by 40 per cent. An ONR spokesman said: ‘A conservative assessment of the inspection results shows that the number of cracks in Reactor Three exceeded the operational limit of 350 cracks in the existing safety case.
‘However, it should be noted that the safety case demonstrates a significant margin beyond this limit and safe operation was ensured.
‘Once we have received the safety case from EDF we will fully assess it and permission will only be granted for the reactor to return to service if we are satisfied that it is safe to do so.
‘This assessment will include consideration of the timing of further inspections.’
A spokesman for EDF said: ‘Nuclear safety is our overriding priority. The most recent results support the work we are doing on the long-term safety case and underline our confidence that the normal operations at the station are unaffected.
‘We are preparing to present a safety case for return to service of Reactor Three to the ONR for their assessment.’
Hunterston is expected to continue operating until 2023, when decommissioning work will begin. It was initially designed to operate until 2011.
Rita Holmes, of the Hunterston Site Stakeholder Group, said: ‘If safety were indeed EDF’s number one priority, then Reactor Three would remain shut down.’
Independent radioactivity consultant Dr Ian Fairlie said: ‘EDF does not have a good handle on the ageing mechanisms inside the reactor. This means that Reactor Three should definitely not be restarted.’
‘Should not be restarted’