Significant progress continues on construction work at the Sellafield Separation Area Ventilation (SAV) project. A number of project milestones have been achieved including the successful dismantling of the slipform rig at 122 metres – what was considered the most hazardous aspect of the stack construction in terms of working at height and risk of dropped loads.
Ian Hudson, NDA Head of Programme for Sellafield said: “This project is a prime example of the interdependencies and complexities of the site. We’re completing a major construction project in order to accelerate the decommissioning of legacy facilities.”
Steve Slater, head of decommissioning and demolition projects, said: “The project team and main contractor Doosan Babcock are really pulling together to deliver this important project which will provide a ventilation capability for the remaining life of Separation Area plants.”
Following the successful completion of the ventilation stack concrete windshield, the construction teams moved to dismantling the slipform rig.
Every aspect of safety was considered before the methodology was approved. The rig was then safely dismantled over a six week period. Completion of this element of work allowed the windshield steel and concrete roof section to be installed.
With the external civil works complete, the fit out of the stack internals could start. The first phase was the installation of the steel support platforms.
There are 19 floors each weighing approximately 3.8 tonnes – which are fabricated off site. Once assembled on site, the floor is winched into position and secured to the concrete windshield.
Monitoring room structure
July saw the monitoring room structure steelwork complete, involving 80 tonnes of steelwork in the construction process. Work has progressed to include the first floor concrete pour and the building external cladding support steelwork. The next phase to make the monitoring room building weather proof started mid August.
Since completion of the plant room steelwork, cladding has been installed to the building structure, making it watertight and allowing the installation of the Heating Ventilation and Air Conditioning (HVAC) plant and equipment and the control, electrical and instruction systems (CE&I) to begin.
HVAC installations have commenced within fan rooms 1, 2 and 3, with the main header ducts installed. These fan rooms are forecast for completion by the end of the calendar year.
CE&I installation has started on the ground and first floors, with the installation of the primary power distribution cable being installed. The plant room switchgear has been manufactured and undergone factory acceptance tests, and is ready for delivery to site.