Work is underway to bury the radioactive remains of Britain’s experiment with fast reactors at Dounreay.
Construction started on a series of underground concrete vaults that will receive up to 240,000 tonnes of low-level radioactive waste from the site’s demolition.
The Nuclear Decommissioning Authority is investing £100 million to clear the redundant site of low-level waste and dispose of it beneath adjacent land.
The new facility is the first of its type to built in Scotland since the 1950s and the first ever to be granted planning permission.
Site closure contractor Dounreay Site Restoration Ltd engaged construction company GRAHAM Construction to design and build the first two of up to six vaults.
GRAHAM Construction is expected to take two years to develop the first phase of the site under a contract valued at £13m. Up to 100 construction jobs are being created.
Subject to regulatory clearance, waste disposal is due to begin in 2014.
Rob Gibson, MSP for Caithness, Sutherland and Ross, cut the first turf today.
He said: "I am very pleased to welcome this next phase of decommissioning Dounreay. Looking after low level waste in this way – near the site and near the surface – is a practical approach.
"It does highlight however the choices to be made to keep within budget which is emphasised by the newly announced contract won by Babcock. Caithness residents deserve to share in the work to build this facility and in all future phases of decommissioning Dounreay."
Nigel Lowe, NDA’s director for Dounreay, said: "Dounreay was at the forefront of the country’s reactor programme when it was first built. Today, as the site opens a new chapter in its history, it is again at the forefront as exemplified by this low level waste construction project. This facility will ensure the material is safely and securely looked after well into the future, utilising modern standards and technologies."
Audrey Cooper, senior project manager at Dounreay Site Restoration Ltd, said: “Cleaning out and knocking down a redundant site like Dounreay generates significant quantities of radioactive waste. This facility provides us with a safe disposal route for much of that waste.
"It is the culmination of a decade of work to identify the best option for looking after this type of waste and obtain the necessary planning consents.
“Nuclear decommissioning worldwide is a huge potential market for British expertise. The profile of this project provides UK companies with a platform to showcase how sound engineering combined with competitive pricing is delivering real benefits for nuclear clean-up in this country.”
Leo Martin, Director at GRAHAM, said: "The decommissioning of Dounreay is a massive undertaking and we are tremendously proud to be playing our part in making it safe for future generations.
"GRAHAM has gained a wealth of civil engineering experience during its long history and we will be bringing all of this knowledge to bear on this project to construct the underground vaults at Dounreay.
"We look forward to delivering this project in a way which benefits both the client and the local community."
Low-level waste typically consists of debris such as metal, plastics and rags that have been contaminated during the clean-out and demolition of facilities where radioactive materials were handled.
By volume, low level waste represents more than 80 per cent of all the radioactive waste generated by Dounreay’s demolition. By radiological hazard, it represents less than 0.01 per cent.
The decommissioning waste is collected in 200-litre drums that are processed on site. Each drum is currently compressed to a fifth of its site and placed inside half-height shipping containers. These containers will be filled with grout to make them ready for disposal.
Each vault covers an area the size of a football pitch and is 20 metres deep. An agricultural-style building will be built over each vault to provide cover during its operation, before each is finally backfilled with grout and capped.
Subject to regulatory consent, the first boxes of waste will be moved into the vaults in 2014 and grouted in place. The last disposals are expected to occur sometime in the next decade. After capping, it will monitored for 300 years, by when 95 per cent of the radioactivity will have decayed.
Radioactive materials at Dounreay – leaflet