Work has begun to remove Sellafield’s most hazardous material.

Highly radioactive liquor has been taken out of one of the oldest parts of the Magnox Swarf Storage Silo for the first time.

The material has been inside the waste store for several decades and new networks of shielded pipes have been built to help get take the material out of the building.

Chris Halliwell, of Sellafield Ltd, said: "This has been one of our biggest technical and engineering challenges to date.

“The first transfer worked just as planned. The team can now press on with meticulously making each transfer, reducing the hazard posed by our biggest current risk."

The clean-up of the Magnox Swarf Storage Silo is one of the Nuclear Decommissioning Authority’s highest priority programmes.

Duncan Thompson, head of Sellafield programme for the Nuclear Decommissioning Authority, said: “It is a highly complex task involving the removal of many different types of waste.

“This work will make Sellafield and the UK a safer place.”

The building contains 22 vertical compartments that store waste from the UK’s first generation of nuclear power stations.

It was constructed without plans for how the waste would eventually be taken out and the building is no longer suitable for long-term storage of nuclear waste.

As a result, solutions are being deployed to retrieve waste from what is effectively a locked vault.

Work to ‘scoop’ solid waste out of the store, using the first of three 350-tonne mobile emptying machines, is scheduled to start next year.

They will be locked into position above each compartment and the waste pulled out through an opening.

It will then be transferred to new buildings at Sellafield for treatment and interim storage, pending final disposal at the UK’s geological disposal facility.

The silo will then be fully decommissioned and demolished.