HUNTERSTON B bosses say they plan to remain in operation until 2023 - despite further calls this week for the plant to close with immediate effect over fresh safety concerns.

A report this week revealed at least 58 fresh fragments have broken off the graphite bricks that make up the reactor cores, causing an alleged risk of blocking cooling channels to the reactor and causing fuel cladding to melt.

Reactor 4 recently restarted for a four month trial period while a safety case is currently being prepared for reactor 3.

EDF chiefs today said the changes pose no risk to the public.

A spokeswoman said: "Graphite debris does not pose a risk to nuclear safety. It is EDF Energy’s job to prove that we understand how debris may affect the reactors in the future.

"We are confident that we can make a safety case in all circumstances to end of life.

"It is regulator's job to make us prove our case and it is our job to provide evidence to uphold our assumptions.

"It doesn’t mean that these ‘worst case scenarios’ are going to happen – in fact these measures should mean exactly the opposite."

A full discussion over the future of Hunterston was raised at the recent community council meeting.

Cllr Ian Murdoch says the latest revelations raise further safety concerns.

He added: "These issues completely support my view that Hunterston is beyond its lifetime and should be shut down.

"We cannot get a 100 per cent guarantee that it is safe.

"I have grave concerns on behalf of my constituents in my ward, the whole of North Ayrshire and the whole of Scotland. "I am not an expert, but someone at this stage must be asking questions."

Conservative councillor Tom Marshall said: "I am not an expert in nuclear although physics was part of my university degree.

"Plain statistics will tell you that nothing is ever 100 per cent safe.

"I am content to listen to what the ONR have to say at the next Site Stakeholders Group meeting in December and hopefully get reassurances.

"If there is any doubt that the station is unsafe to operate of course I would be pushing for its closure, but I am reassured, at this stage, that it is not unsafe."

Green MSP Ross Greer said: "These latest revelations show how irresponsible it was to bring reactor 4 back online this year, given that lack of necessity.

"Significant uncertainty isn’t a phrase I want to see in reports about graphite bricks literally crumbling and debris falling into the reactor itself.

"Reactor 4 needs taken back offline immediately, reactor 3 should never be turned back on and 2019 should be the last year of power generation at the plant.

"EDF’s attempts to drag Hunterston well beyond it’s intended lifespan needs to be stopped now."