Over 2,300 m3 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. 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.

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 Enhanced Actinide Removal Plant (EARP) and Effluent Plant Services Building.

Speaking about the achievement, 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. The 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.”

Paul Bailey, Manufacturing Manager for both EARP and STP said: “STP 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 added:

“This achievement represents the focus of the Waste and Effluent Disposition directorate at Sellafield: to reduce hazard and risk to our employees, the public, and the environment by dispositioning waste to either final disposal or to a safe form awaiting final disposal. Well done to the team.”