Dounreay Site Restoration Ltd has awarded GRAHAM Construction a £4.3 million contract to design and build a plant for the disposal of low-level radioactive waste from the clean-up and demolition of the site.

GRAHAM Construction will design and build a plant to encapsulate waste in grout inside containers before the containers are placed in a series of underground disposal vaults currently under construction.

“Workers who are dismantling the site collect much of the low-level radioactive waste in drums,” explained Stewart Henderson, project manager at DSRL.

“The drums are checked, compacted and the ‘pucks’ stacked inside metal containers. These containers are stored on the site at present. In 2014 we intend to begin emplacing the containers in the ground in a series of vaults now under construction.

“This plant will grout up the inside of each container to fill the void spaces between the pucks before the container is moved into the vault.

“As the vault fills up, we’ll grout the spaces in between each container as well, before the whole area is covered in concrete.

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“It’s all about getting the waste into a condition that is safe for future generations and this plant is a key part of that.”

Items small enough to be drummed will fill an estimated 7000 containers, each weighing some 40 tonnes after grouting. Currently, the site has 750 containers in store ready for grouting and disposal.

Work on the design of the plant gets underway this week and construction is due to begin next summer. It is expected to take five months to complete.

The contract – issued on behalf of the Nuclear Decommissioning Authority - was tendered through the Official Journal of the European Union.

GRAHAM Construction is also the main contractor for the construction of the first two disposal vaults.

GRAHAM has maximised the use of local labour, equipment and materials since commencing work on the project last year and is seeking to utilise the skills and experience of local companies wherever possible on the latest contract.

Leo Martin, Director at GRAHAM said: “This latest contract award is a real endorsement of the work GRAHAM has already undertaken on the site at Dounreay.

“We are already making significant progress on the construction of the two sub-surface vaults for the disposal of solid low-level radioactive waste from the site clean-up.

“The restoration of Dounreay is a massive undertaking and the work we have undertaken gives us a tremendous platform for attracting further work in the nuclear industry both in Scotland and across the UK.”

The disposal of waste from the site’s decommissioning is expected to begin in 2014 and will continue until the site has been cleared by 2022-25.

It’s estimated the clean-up and demolition of the site will generate up to 175,000 cubic metres of low-level radioactive waste.

The site has planning permission for up to six underground vaults but is working to reduce the number needed through a vigorous waste minimisation programme.

(GK)