Sellafield is seeking permission to store extra nuclear waste in a specialised facility on the site for up to 100 years.

An application has been lodged with the county council to built two extra plant rooms in the existing Self Shielded Box Storage (SSBS) facility.

The facility itself was granted permission three years ago and completed earlier this year.

It is designed solely for the interim storage of boxes of waste from the Magnox storage pond which ceased operations 25 years ago.

The waste would be stored in the facility as an interim measure until a long term disposal solution – such as a geological waste facility which the Government is currently consulting on – was created.

A Sellafield spokeswoman said: "Our mission is to safely clean-up the Sellafield site.

"This involves removing nuclear materials from old facilities and transferring it to modern, safer stores.

"This year we completed the construction of a new store which will hold hundreds of self-shielded boxes – these are specially built 30-tonne metal containers which safely hold radioactive waste and provide the necessary shielding from the waste inside them.

"We have already worked with our nuclear regulators and local authorities to ensure the planning permission is in place for the store to hold these boxes, but want to be able to speed up the hazard and risk reduction in the future by having the flexibility to store additional types of nuclear material if necessary.

"This will help us to continue reducing the hazards posed by these legacy plants."

As well as creating the extra plant rooms, the security fence needs to be raised by four-metres.

The application has been lodged with the county council as it is the authority which deals with minerals and waste matters, but Copeland Council has been consulted on the plans.

At a meeting earlier this week, Copeland planning officer Heather Morrison said: "In the absence of any long-term disposal options being available for this material, interim storage solutions are required."

The council raised no objections to the application.