An inconspicuous building, hugging the north coast of the Dounreay site and nestling in the shadows of PFR, is the old active effluent treatment plant.
The plant was built to filter and neutralise effluent streams arising from the decontamination of components that had been in contact with the reactor’s liquid sodium metal coolant.
As time and technology progressed and the plant no longer conformed to modern regulatory standards a new £3.3m effluent treatment plant was designed and constructed back in 2005 and operation commenced the following year.
Work has now begun to dismantle the old redundant facility, starting with the hoisting of the above-ground structure which provides a protection barrier over the waste treatment tanks in the basement below.
A purpose-built weather enclosure has been constructed and will be complete once the giant slabs of concrete blockwork have been removed – consisting of twenty blocks weighing 6.5 tonnes each. This is an intricate operation because each block is currently slotted in place like a huge Tetris. Work is expected to begin later this month well ahead of schedule.
The sludge currently contained within the five subsurface tanks is due to be encapsulated in cement. The next phase of operations is to accelerate the removal of the tanks and adjoining pipework infrastructure, by utilising the newly constructed weather enclosure. This will save additional cost being incurred at a later stage and the final phase of demolition will then commence.
“We’re all very enthusiastic about this project,” explained project manager Maryrose Bailey.
"There’s been extensive participation from many areas of the site as well as PFR during the planning and development stages. Project supervisor Robbie Falconer has been working closely with our sub-contractor Doosan Babcock to address the safety aspects whilst still improving efficiency and we’re looking forward to setting to work on the sludge encapsulation process.”