The world’s oldest nuclear waste store is ready to be emptied.

Experts at the Sellafield site have cut the sixth and final hole in the Pile Fuel Cladding Silo, a locked vault that was never designed to be opened.

The holes will allow radioactive waste to be removed from one of the site's most hazardous buildings.

Six giant steel doors now provide a safe barrier between the outside world and the waste inside the silo, until it starts to be removed by a ‘grabbing’ machine.

The Pile Fuel Cladding Silo was built in the 1950s when the site's purpose was to make material for nuclear weapons.

Sellafield Ltd said getting access to the waste inside was one of the most complex engineering challenges in the site’s history.

Steven Carroll, head of the PFCS programme, said: “It’s an early Christmas present to complete the work three months early and under budget.

"We can now say ‘the silo is ready for retrievals’ for the first ever time.

“Getting access to this nuclear waste store which was built with no thought to how it would be emptied has been an incredible engineering challenge, involving years of planning and preparation, hundreds of dedicated people and many millions pounds of investment.

“It’s also involved a massive team effort with our main contractor partner Bechtel Cavendish Nuclear Solutions and businesses such as James Fisher Nuclear and Shepley Engineers.

“Reaching this landmark allows us to fully focus next year on manufacturing and installing all of the equipment which will reach in, retrieve the waste and allow it to be safely exported to the new facility for safer storage.”

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The level of challenge involved with this facility was unparalleled, a Sellafield spokesman said, due to the age of the building, the lack of historical information about the waste, the atmosphere inside the silo and its position on one of the most congested sites, anywhere in the world.

Jim Delaney, project manager for Bechtel Cavendish Nuclear Solutions, said: "To reach this major milestone significantly ahead of schedule and with a dramatic reduction of overall costs is a testament to the excellent teamwork on this critical project."

Each section of concrete has been cut away in a single piece and withdrawn into a containment bag. Six containment doors are then lowered over the apertures and closed.

To remove the waste, a crane will extend through the cut holes, a grabber will then drop down to scoop the waste up, lifting it out of the container and back through the hole.

It will then be dropped into a specially designed metal box, for safe and secure storage in a modern facility.