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SMF Sellafield
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Dragon Shield Doors
Cairnhill was contracted to design, fabricate, test, and deliver five Dragon Shield Doors for the DRAGON nuclear decommissioning site in Dorset. The project required specialist equipment, bespoke lifting solutions, and precise installation to safely handle heavy shield blocks. Cairnhill overcame design challenges to deliver high-precision, fully tested doors within a 20-week contract, valued at £1m with an additional award for £600k for onsite installation.
Cairnhill was appointed to supply of five dragon shield doors for the Dragon decommissioning site in Winfrith, Dorset. The scope of work included the fabrication, testing, and delivery of the doors, with a contract value of £1m. Following the successful completion of the manufacturing phase, Cairnhill was awarded the installation works onsite, valued at an additional £600,000.
The DRAGON facility, a research reactor constructed in the 1950s and decommissioned in 1975, has undergone progressive decommissioning, including the removal of radioactively-contaminated equipment located outside the reactor core.
The following phase of this contract involved the remote decommissioning of the reactor core itself to enable safe disposal.
Cairnhill supported this phase through the design, fabrication, and installation of specialist shield door systems within the reactor facility. Manufacturing the shield doors and undertaking a comprehensive FAT testing, this included acceptance trials of the screw jack assemblies, installation of the Hepco track system, and the precise installation of running rails to meet stringent bearing tolerances. The doors were subsequently installed onsite.
The project presented technical challenges due to incomplete design information at the outset, particularly in relation to testing and final execution. Tasked with designing bespoke lifting brackets to facilitate the installation of the shield blocks, and further developing a testing process to verify the door’s capacity to safely lift the required loads, this was a crucial step for both testing and installation phases.
During the FAT phase, Cairnhill provided valuable, technical input into the support steelwork setup and screw jack installation, contributing to a safe and successful onsite delivery.
