Hunterston ‘B’ station director Colin Weir has said that the cracks found in the graphite core of their reactor were predicted, and will not affect the future operation of the power plant.

News headlines on the BBC on Monday morning - ‘Cracks may threaten power plant’ - speculated that the future operaiton of Hunterston B could be in doubt, with some environmental campaigners calling on Hunterston to close but this was robustly dismissed by EDF Energy who say the predicted cracks were well within their safety limits.

Two of about 3,000 graphite bricks in the core of reactor four were affected which were discovered during a routine inspection in August.

Although deputy First Minister Nicola Sturgeon said the issue was “hugely concerning” to the public and that the ‘Scottish government was seeking reassurances’, Hunterston B site managers, past and present, and moved to dispell any fears about the future operation of the ‘B’ station, which opened in 1976.

Colin Weir, Station Director at Hunterston B said: “Every time we take the reactor out of service for planned maintenance we inspect the graphite core which is made up of around 6,000 bricks. During the current Hunterston outage we found two bricks with a new crack which is what we predicted during Hunterston B’s lifetime as a result of extensive research and modelling. It will not affect the operation of this reactor and we also expect that a few additional cracks will occur during the next period of operation. The small number of cracked bricks found during routine inspection is in line with our expectations, the findings have no safety implications and are well within any limits for safe operation agreed with our regulator.” Brian Cowell, director of nuclear operations at EDF Energy, and former ‘B’ director said on BBC Radio Scotland: “What we have found here is that our models and mathematical assumptions are absolutely underpinned by our findings. Therefore, they have revalidated again the fact that we have got these massive safety margins and the (reactor) cores will behave as we have predicted in extreme events, which is exactly what we want.” Mr Cowell added: “They are safe.” Mr Weir’s assertions were backed by Brian Cowell, director of nuclear operations at EDF Energy.

He said: “What we have found here is that our models and mathematical assumptions are absolutely underpinned by our findings.

“Therefore, they have revalidated again the fact that we have got these massive safety margins and the (reactor) cores will behave as we have predicted in extreme events, which is exactly what we want.” Mr Cowell added: “They are safe.” The reactor was restored to service on Sunday evening, after EDF received approval from the Office for Nuclear Regulation.

However, it is not yet supplying electricity to the grid as the start-up process takes time.

An EDF spokesman said: “The graphite bricks in the core can crack from the inside out, which is known as a “bore” crack or from the outside towards the centre, which is known as a “keyway root” crack. This ageing and degrading of the graphite is expected. The bore cracks are expected early on in life and the keyway root cracks are expected later on in life.

“At Hunterston B less than 1% of the bricks have axial bore cracks which happened early in life and have now stopped cracking. We were expecting the keyway root cracks, as they have appeared, later on in the life of the reactor core. The current findings of keyway root cracks affect less than 0.1% of bricks.

“The safety case has a tolerance for up to 10% of both types of axial cracked bricks, which itself is a conservative limit and contains lots of safety margin. At Hunterston B, you can see that the percentage of bricks axially cracked from the inside out (bore cracks) or from the outside in (keyway root cracks) is well below that figure.” Cunninghame North MSP Kenneth Gibson posed a question at the Scottish Parliament today in relation to safety concerns at Hunterston Speaking at the Fairlie Community Council meeting on Monday evening, Mr Gibson said: “As I understand it, there is no danger whatsoever. It is not just in our best interests, but also the nuclear industry’s best interests, that everything is done by the book. Although I am not supportive of nuclear power, it is important to resist any scare stories, unless there is any substance to them.” Speaking at Monday night’s meeting, Fairlie community councillor Joan Downie branded it as a ‘scare story’ and ‘unnecessarily frightened people’.

Rita Holmes, the chairman of the Hunterston site stakeholders group, said: “I have every faith in the dedicated workforce at Hunterston B. It is just getting to the end of its life, it was supposed to close in 2011.

We have to rely on the ONR and SEPA to regulate stringently. Eventually it won’t be worth EDF’s while repairing the ageing reactors - not just Hunterston - it is a concern to me.”