In order to reduce hazards at the Sellafield site, Intermediate Level Waste (ILW) are moved from the Legacy Magnox Swarf Storage Silos (the ‘Wet’ Silos) to modern safe storage by utilizing the existing SDP facility, modified to treat and package the waste to a quality suitable for interim safe storage.
The existing Drypac facility was constructed in the 1990s and was originally designed to treat ILW from the ‘Wet’ Silos and clino/pond sludge from the effluent treatment plant on the Sellafield Site.
During the construction of the original plant, changes resulting from improved knowledge of waste feeds and the significant challenges in satisfying the acceptance criteria for the UK Radioactive Waste Management Directorate were amongst the drivers which led British Nuclear Fuels Ltd. (BNFL) to carry out a major review into the strategy of remediation at Sellafield. The treatment and packaging of this ‘Wet’ Silo waste will take place within the existing SDP building with the additional requirement for one main annex, wrapped full length on the east side of the existing building with a partial return on the north elevation.
Working as part of an integrated target cost, design and construct project team, Halcrow’s role was to provide Civil, Structural and Architectural detail design and Building Services (Mechanical, Electrical, C&I). Halcrow was responsible for design of all civil engineering modifications, new building structures and all building services to support the new process, including HVAC. Drawing from Halcrow's unique expertise in seismic engineering, the process and structures were all seismically qualified.
The first stage of the contract is complete, with two further stages to follow. Work on the project was completed up to scheme design for the process (up to prototyping) and detailed design for the structural and building services modification (the scope of which was provided by Halcrow).