Officials have formally agreed to pile more pressure on the Government to make Sellafield’s Calder Hall the first reactor in the UK to be decommissioned.

Copeland Council’s chief executive Pat Graham and nuclear portfolio holder David Moore have been given the green light to build a case setting out why it should be top of the list.

A council report has claimed that if decommissioning is delayed, the asbestos in the reactor will pose a risk to workers, while maintenance costs will become ‘unsupportable’.

The authority’s strategic nuclear energy board wants to fast-track the dismantling of the world’s oldest industrial-scale nuclear power station at Sellafield.

Councillor Raymond Gill, board chairman, said: “It makes sense that the first one built should be the first one decommissioned.”

The nuclear board voted to delegate authority to  develop the case for accelerated decommissioning.

Calder Hall is one of 11 reactor sites around the country and the Nuclear Decommissioning Authority is now reviewing the timing and sequence of its nationwide clean-up operation.

At present the defuelling of Calder Hall is due to be finished in 2019/20, and would not enter a care and maintenance status until 2034.

The argument for tackling the Sellafield-based reactor first includes the continuing risk it poses to workers and the public.

The report said: “As the oldest Magnox reactor, the deterioration of the building fabric and the potential for significant quantities of asbestos to be present pose risk to workers.

“The cost borne by the taxpayer associated with maintaining the building in a safe state for a long period of care and maintenance could be significant and could increase over time to meet future regulatory requirement.”

The report concludes that the reactor could deteriorate to the point that the cost of keeping it compliant with environmental regulations becomes “unsupportable”.

Because there are already waste stores and treatment facilities on Sellafield, decommissioning could involve “significantly fewer” off-site transports than some of the other Magnox sites dotted around the country.

The accelerated clean-up of Calder Hall could also create jobs to offset some of the 3,000 “surplus roles” expected at Sellafield over the next four to five years.

The skills and technologies learned from work on Calder Hall could then allow nuclear workers to lead the way in the decommissioning of other reactor sites across Britain as well as internationally.

When the station closed on March 31 2003, the first reactor had been in use for nearly 47 years.