Work has begun on building an underground tomb to store 240,000 tonnes of low-level radioactive waste from the Dounreay nuclear power plant – the low level waste includes: concrete, rags, tools, glass, paper, clothing and scrap metal registering low levels of radioactivity.
The Nuclear Decommissioning Authority (NDA) is spending £100m at the Caithness nuclear site and 100 jobs are expected to be created in the construction and maintenance of six 65ft-deep vaults to store nuclear waste at Dounreay – each vault is planned to be about the area of a football pitch in size – Graham Construction will build the first two of up to six vaults.
This is the first such site to be built in Scotland since the 1950s and the first ever to receive planning permission.
The low-level decommissioning waste is collected and processed on site, it is then packed into 200-litre drums, compressed to a fifth of their size and placed inside half-height shipping containers – these containers will be filled with grout to make them ready for burial in the vaults.
Low-level waste makes up more than 80% of the volume of all the radioactive waste generated by Dounreay’s demolition but represents a radiological hazard of less than 0.01% of Dounreay’s total.
The Dounreay low-level radioactive waste is not ostensibly considered dangerous to handle but it must be disposed of with more care than ordinary industrial waste as its radioactivity is greater than the level permitted for ordinary landfill sites – the waste is however below the level at which special precautions are required.
A protective building will be built over each vault providing cover until each vault is backfilled with grout, capped, covered with earth and landscaped before being fenced off to the public. It will require 300 years for the radioactivity to diminish to safe levels (95% less than its current level) and during these 3 centuries the waste will be monitored.
Audrey Cooper, senior project manager at Dounreay Site Restoration Ltd which is charged with the decommissioning, 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.”
This news follows the NDA confirming its controversial plans to transport 44 tonnes of highly radioactive nuclear fuel by train from Dounreay to Sellafield in Cumbria for reprocessing over the next four to five years. A number of environmental groups have already expressed concern.
A final decision has yet to be taken on another 56 tonnes of nuclear fuel at Dounreay which, if kept in Caithness, would need expensive security at all times.
Over the next three to four years, more than 150 tonnes of intermediate level radioactive waste is set to leave Dounreay and go to a storage site in Belgium. The material will be shipped by sea – the material is being collected by Belgian contractors – a vessel has already arrived to take the first of 20 shipments.
SNP MSP for Caithness, Sutherland and Ross, Rob Gibson, is due to cut the first turf at the site next to the nuclear plant, which is being demolished.