The decommissioning of the former Atomic Energy Research Establishment at Winfrith in Dorset is being carried out by the nuclear site licence holder United Kingdom Atomic Energy Authority
(UKAEA). Following recent government changes, the United Kingdom's Nuclear Decommissioning Authority (NDA) has now set up contracts with UKAEA for delivery of the site clean-up programme
but UKAEA retain responsibility for the direction and control of the work and all safety matters.

In July 2000, NUKEM Limited was contracted to design, build and commission a sludge conditioning and treatment plant to deal with the active sludge stored in External Active Sludge Tanks (EAST)
at Winfrith. The sludge was generated during the operational lifetime of the Steam Generating Heavy Water Reactor, currently in the early stages of final decommissioning. The purpose of the plant is
to treat the radioactive sludge by encapsulation into a cement matrix, inside 500litre steel drums. After completion, drums are moved in an overpack to a dedicated store within the Winfrith site.
The article describes the operation of each area of the process and will reflect on operational experience obtained to date from the first privately operated waste encapsulation facility in the UK
treating radioactive sludge. The scope of the contract includes the recovery and processing of all sludge as well as ultimate decontamination and demolition of both the EAST facility and WETP.