Final Drum through WETP

Nuvia Limited is the only private contractor in the UK to have designed, built, commissioned and operated an intermediate level waste (ILW) treatment plant. Under contract to UKAEA (now RSRL – Research Sites Restoration Limited) the plant was built to deal with ~380m3 of ‘active’ sludge stored in four External Active Sludge Tanks (EAST) at Winfrith. The sludge was generated during the operational lifetime of the Winfrith Steam Generating Heavy Water Reactor (SGHWR).

The operational process involved the sludge being fluidised and then pumped from the tanks to the treatment plant where it was encapsulated in cement; allowed to ‘cure’ and then transported to the Treated Radwaste Store located on another part of the site.

Once in full production the drum throughput in WETP (Winfrith EAST Treatment Plant) steadily rose. At its peak it was processing one hundred 500 litre stainless steel drums a month. In 2009 the 1000th drum was produced and the project reached its most challenging point; to deal with the thickest sludge known as the ‘Heel’ which also contained other materials such as sand and gravel. Nuvia developed an innovative solution that enabled the collection of smaller quantities of sludge that were then conditioned and fluidised before being pumped to WETP. The last drum – number 1068 – left the plant at the end of April 2010. Nuvia and RSRL jointly developed safe and practical methods to deal with the sand and gravel once it had been separated from the sludge. In mid June 2010 all material, sludge, sand and gravel was finally removed from the tanks removing a significant legacy on the Winfrith site; an outstanding achievement and one to be applauded.

Plant Manager Madoc Hagan and his team not only completed the operations successfully but with an exemplary safety record.

“It has been a challenging project that has drawn on skills from across the Company – it has been fantastic teamwork within Nuvia and with RSRL. We have gained vast experience on dealing with pond sludges that we hope will not be wasted.”

Regional Director Steve Parkinson said,

“Having been involved with the project since the start I am immensely proud of the achievements of the Nuvia / RSRL team. We have demonstrated that we can deal with legacy liquid wastes safely and economically whilst being able to develop solutions for materials that were not anticipated.”

Nuvia’s MD Keith Collett said,

“The team at WETP is to be congratulated for yet another ‘first’ in a long line of unique achievements at Winfrith – it is something for Nuvia to celebrate.”

Andy Staples RSRL Operations Director commented

“The delivery of the WETP programme has helped achieve the ongoing hazard reduction work at Winfrith and is a significant milestone in the site’s eventual remediation”.

WETP has been a flagship project for Nuvia and RSRL and throughout its operations was visited by many clients, regulators and other stakeholders from the UK and overseas all of whom applauded its success. However, despite innovative attempts by Nuvia to secure WETP as a centre for other UK sludges the plant operations have now ceased and Nuvia is decommissioning WETP as safely and effectively as it was operated.

Nuvia is currently working closely with Sellafield Limited on the design and construction of the SDP (Silos Direct encapsulation Plant) and is drawing on their experience from WETP. This facility is a key enabler for the treatment of wastes from the Magnox Swarf Storage Silos. Successful completion of this project is a major milestone in achieving Sellafield Limited’s strategy towards safety and environmental improvements by risk hazard reduction.