Two different UK projects have celebrated major milestones: the successful transfer of liquid waste from a fifty-year old storage silo at Sellafield, and the opening of a new low-level waste storage facility.
|Magnox Swarf Storage Silo
(Image: Sellafield Ltd)
The successful transfer of 14,800 litres of radioactive liquid waste from the Magnox Swarf Storage Silo at the Sellafield site marks the start of a so-called Liquor Activity Reduction (LAR) process. Magnox fuel cladding was stored underwater in 22 individual compartments inside the silo, which was built in the 1960s, and extended in the 1970s and 1980s.
The LAR process will see the transfer of the silo liquor to the SIXEP ion exchange effluent treatment plant for treatment. After each transfer, the silos will be topped up with clean water, with the process repeated on a weekly cycle, gradually reducing the activity of the silo liquor through dilution. After about 3-4 years the activity of the liquor wastes will have been reduced by about 90%, and the solid waste inventory will then be removed.
Head of program delivery Hugh Bourque described some of the challenges faced. "The active liquor has had to be pumped from the compartments and transferred across the Sellafield site in a high level shielded pipebridge. The liquor is then treated in our SIXEP facility which filters contaminated water using a special sand called clinoptilolite to remove radioactivity from the effluent," he explained. The SIXEP process captures more than 99% of the radioactive feed in a solid form.
New vault for LLW
Meanwhile, the UK's Nuclear Decommissioning Authority (NDA) has officially opened a new state-of-the-art storage vault for low level nuclear waste at its Drigg site.
The 110,000 cubic metre Vault 9 has been designed to meet stringent nuclear and environmental regulations, with the emphasis on the use of strategies such as waste minimization and recycling of metals to make the best use of the site.
NDA head of waste and nuclear materials Phil Davies described the vault's role as vital for the UK, which as well as operating nuclear plants is tackling legacy wastes dating back to the very earliest days of nuclear power. "Without Vault 9 important nuclear cleanup programs and operations would simply stall," he said.
Vault 9 has another claim to fame: a particular feature of the vault project was a decision to ensure that most of the construction materials were delivered to the site by rail, which according to NDA reduced the potential number of road deliveries by 27,500.
Researched and written
by World Nuclear News