Latest news
Clean up milestone reached at Sellafield
A major milestone in radiological risk reduction and nuclear clean up has been reached on the Sellafield site.
Over 2,300 cubic metres of historic medium active (MA) solvent has now been transferred and processed through Sellafield’s Solvent Treatment Plant (STP), representing over ten years work by the teams involved.
STP was built to treat both the historic MA solvent inventory and future Low Active (LA) arisings from both the Magnox and Thorp plants, respectively.
The effluent produced as part of Sellafield’s reprocessing cycle comprises a mixture of tributyl phosphate (TBP) in diluent odourless kerosene (OK). Traditionally stored in tanks within the site’s MA tank farm, STP was brought online to provide a treatment process for this particular waste stream.
STP removes the radioactivity from the solvent and treats it so that the OK can be combusted and the TBP converted into an aqueous form, suitable for discharge to sea (via the Segregated Effluent Treatment Plant) within the agreed limits set by our regulators. Alternatively, if the material requires further treatment it is sent to the Enhanced Actinide Removal Plant (EARP) where the bulk of the activity is then sent for encapsulation in the Waste Packaging and Encapsulation Plant.
In reaching this target, STP has fulfilled a large proportion of what it was designed and built for; the legacy of historic solvent currently held in storage tanks on the site has been removed. STP will now continue to provide buffer storage for future solvent arisings from current reprocessing operations.
The plant began treating the historical stocks in 2000 and is managed by a shift team of 41 employees, also responsible for operating EARP and Effluent Plant Services building.
Head of the Effluent and Encapsulation Plants, John Butler said: “For at least the last quarter century the MA tank farms have stored backlog long-term liquors awaiting processing. EARP and STP provided the treatment route for these legacy liquors, and the successful operation of these plants has enabled a very significant environmental and radiological hazard to be reduced.”
Shortly before the final batch of solvent was processed in STP, two of the plant’s longest serving employees, Andrea Routledge and Dave Mellor commented on the achievement:
“It has been an honour and privilege for us to work on such a unique and successful project and to finally achieve the historic solvent target after 10 years of hard work. We have excellent operations and engineering teams who have made this possible.”
Paul Bailey, manufacturing manager for both EARP and STP said: “The Solvent Treatment Plant is a unique facility which has faced its own unique challenges along the way. Despite this, the plant has been very successful in its operations over the last 10 years.
“I have had the pleasure of working with very dedicated teams - initially in engineering during the commissioning phase and now in operations as the manufacturing manger of the plant.”
Congratulating the team on behalf of the directorate, Mike Johnson, Waste and Effluent Disposition Director said: “It’s been a privilege to work with this dedicated team as they successfully dispositioned this legacy waste.
“Their achievement represents the focus of the Waste and Effluent Disposition directorate: to reduce hazard and risk by dispositioning waste to either final disposal or to a safe form awaiting final disposal. Well done to the team.”
