Waste emplacement begins at Dounreay disposal vaults

Tuesday, 19 May 2015

The first two vaults of the new low-level waste (LLW) disposal facility at the UK's Dounreay site has begun accepting waste. Up to four additional vaults could be constructed at the facility.

The inside of one of the two vaults completed at Dounreay (Image: Graham Construction)

The Dounreay site applied to Highland Council for planning permission to build six LLW disposal vaults in July 2006. The council granted planning permission in April 2009. Graham Construction won a tender to design and build the facility and construction began in November 2011.

Completion of construction of phase one of the facility, comprising two vaults, was ceremoniously celebrated in April 2014. One of the vaults will be used for disposal of LLW arising from previous operations at Dounreay, while the other will accommodate waste generated by decommissioning operations at the site.

Active commissioning of the associated encapsulation plant began on 24 April when a container packed with LLW was filled with grout. This container has now been placed within the LLW vault, Dounreay Site Restoration Limited (DSRL) announced today. Meanwhile, packages of demolition waste have also been transferred from storage on the Dounreay site to the demolition LLW vault.

DSRL has now confirmed that phase two of the facility will also be required and will comprise a further two LLW vaults to accommodate further waste from decommissioning.

"To meet the site decommissioning requirements phase two would be required by 2020," the company said. "However, DSRL is planning to bring the construction program forward within the overall portfolio of site projects."

It added, "Work continues to assess the waste arising rates and total waste volumes and this will influence the program for construction and operation of the vaults and any requirement for phase three."

The facility will be used for the disposal of up to a maximum of 175,000 cubic metres of solid LLW, which is expected to be generated during the decommissioning of the Dounreay site, in addition to waste that will be retrieved from a series of historical LLW pits there.

LLW typically consists of debris such as metal, plastics and rags that have been contaminated during the clean-out of facilities where radioactive materials were handled. By volume, LLW represents more than 80% of all the radioactive waste generated by Dounreay's demolition. However, by radiological hazard, it represents less than 0.1%, according to DSRL.

When the UK's experimental fast reactors at Dounreay have been cleared away in 2025 the vaults will be sealed and the surface restored. The site will then be monitored for 300 years, by which time 95% of the radioactivity will have decayed.

Researched and written
by World Nuclear News