Radioactive waste was historically consigned to the 65 metre deep shaft and the silo, an underground waste storage vault, over several decades starting in the late 1950s. Now the higher activity waste must be retrieved and repackaged, suitable for long-term storage in a safe modern facility.
Retrieving the waste from the shaft is one of the most complex decommissioning jobs that the site must complete, and innovative concept designs evaluating the techniques and equipment to be used for removing and processing the waste have been developed over the last decade.
In 2007, in a world first for Dounreay, the shaft was encircled in a boot-shaped ring of grout to isolate the radioactive waste from the environment, preventing large volumes of groundwater flowing into the shaft during waste retrieval and becoming contaminated.
Last year DSRL awarded the £7.5 million contract for the advanced transition works at the shaft and silo to Nuvia and Graham Construction. The work includes the rerouting of existing services as well as construction and demolition works, preparing the waste facility to be emptied of higher activity waste.
Project manager Kirstin Polson said:
Cleaning out the legacy waste from the shaft and silo is one of the most significant decommissioning projects at Dounreay.
We are now at the enabling phase of this major project to retrieve the waste using remote equipment in a specially designed facility, and to process it for long term safe storage.
Dounreay is Scotland’s largest nuclear decommissioning project and is widely recognised as one of Europe’s most complex nuclear closure programmes. The work is being delivered by DSRL, a wholly owned subsidiary of the Nuclear Decommissioning Authority.