New UK waste facilities completed
Two new radioactive waste facilities have opened in the UK. The first two vaults for the disposal of low-level waste have been completed at Dounreay, while the first intermediate-level waste (ILW) has been put into a new interim storage facility at Berkeley.
A ceremony was held yesterday to mark the handover of the first two underground disposal vaults from contractor Graham Construction to site manager Cavendish Dounreay Partnership and site licence holder Dounreay Site Restoration Ltd (Image: Cavendish Dounreay Partnership)
A total of 243,000 cubic metres of rock were excavated since construction of the two vaults began in November 2011. Some 7600 cubic metres of concrete, 1330 tonnes of reinforcement and 260 tonnes of structural steel were used during their construction.
Subject to regulatory and other approvals, the first containers of waste are due to be moved off the Dounreay site later this year, filled with grout and placed in the vaults. Once each vault is full, it will be back-filled with grout to create a monolithic block. Up to six such vaults are planned at the site.
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 at the site. 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 0.01%, 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.
The first two vaults and ancillary plant were developed at a cost of some £20 million ($34 million). The total cost of managing the LLW through the closure program is expected to be around £110 million ($185 million).
Chairman of Cavendish Dounreay Partnership Roger Hardy commented, “Without these new facilities, we could not complete the clean-up and closure of the site, so today’s handover is a major step forward in our work to decommission this site and return it to the Nuclear Decommissioning Authority (NDA) in a condition that is safe for future generations.”
Meanwhile, the first container holding intermediate-level waste (ILW) has been placed inside a newly-constructed interim storage facility at the Berkeley nuclear power plant, whose two Magnox units were shut down in the late 1980s. ILW comprises a range of material including debris from the fuel elements, resins, sludges and graphite.
In 2010, after 21 years of decommissioning work, the units became the first to be sealed up and placed in ‘safestor’, a passive state in which the defuelled and extensively decommissioned units will be monitored and maintained until the site is completely cleared in about 65 years’ time.
The NDA’s head of programs Brian Burnett said, “The focus now is on retrieving, packaging and storing the waste on site to enable Berkeley to enter ‘care and maintenance.’ This is an important step on that path.” Berkeley is expected to enter the care and maintenance phase, when key hazards have been reduced, in 2021.
Once decommissioning at Berkeley is completed, the ILW storage facility will hold some 850 waste packages where they will be kept until a national disposal facility becomes available.
Source: World Nuclear News