At Sellafield Nuclear Decommissioning, Reprocessing and Waste Management Site in Cumbria, Propump Engineering’s foamed concrete has been used to fill a redundant underground tank as part of a long term maintenance package delivered by Hertel.
Working on the Sellafield site for more than 20 years, industrial services contractor Hertel required a lightweight infill system for the decommissioning of a stainless steel underground tank. As the weight of traditional grout would place unnecessary loading on an adjacent safety critical structure, Propump’s foamed concrete proved the most suitable and versatile solution.
Supplied to achieve a density range of 1,000kg/m3 – 1,100 kg/m3, the foamed concrete also offered a simple application in a challenging location. Regularly used to fill underground voids, encapsulate pipes and create flat screeds, foamed concrete is pumpable, self-compacting and can mould itself to the shape of any void.
“The challenge on this project was the tank was located in a secure area with no access for placing equipment,” said Ian Vickers, Project Manager at Hertel. “This was resolved by positioning the mixer/pump outside the area, and feeding the hose through a corner of a secure fence – undone under security presence whilst the operation was carried out – and then secured on completion.”
Due to the location and sensitive nature of the works, the application had to be carried out in three pours. This was due to the tank being 2.5 metres deep – the recommended depth to prevent hydrostatic pressure depleting the air entrainment – and the risk that heat from hydration could affect the tank’s integrity.
“David Aldridge of Propump attended site to train the Operatives involved in the use of the Propump equipment and foam chemicals on the day of the first pour,” he added. “The training was delivered in an interactive manner which the Operatives could easily understand, detailing each step from mixing and pumping to cleaning the equipment on completion.”
With the application completed in three stages, the first pour was witnessed by Propump and the Sellafield Senior Concrete Quality Controller (SCQC), with test cubes confirming the correct density had been achieved. The final two pours were then completed to an equally high standard by the site operatives and with the Sellafield SCQC in attendance.
Thanks to the fast and reliable installation of Propump’s lightweight foamed concrete, Hertel’s programme of works was completed on time and on schedule.« Foamed concrete gives brownfield sites the green light