Progress continues with the installation of the first of two Bulk Storage Tanks (BSTs) being fitted into our SIXEP Continuity Plant (SCP). Due to their enormity, the tanks can’t be delivered to the Sellafield Ltd site fully built. Instead, they are transported in ‘tier’ sections and assembled on-site – there are five tier sections and a dished head for each tank.
Back in May last year, we reported the arrival of the first section of a BST, followed by the delivery and welding of the dished head’ in July. The project team has now reached another important stage with the safe delivery of the latest tier section, which will be welded beneath the upper sections already in place.
Once fully assembled, each tank will stand an impressive 14.8 metres tall and 7.6 metres in diameter.
The assembly is being carried out by Mammoet and Altrad Motherwell Bridge using a top‑down construction method. This involves suspending the structure from above and building it downward, beginning with the top dished head. In the most recent lift, the welded dished head and Tier 5 were raised to allow Tier 4, the latest arrival, to be positioned underneath.
A video of the lift – showing the dished head and Tier 5 being raised before Tier 4 is slid into place – can be viewed by clicking here.
Dave Devine, mechanical engineer, explained the level of planning involved in getting these components to site. He said:
“Before each component leaves Bendalls in Carlisle, the deliveries are meticulously planned between Altrad Motherwell Bridge, STL Logistics Ltd, the highways agency, and police. Once they arrive at Sellafield, the responsibility then includes the Aligned Delivery Team (ADT) to ensure there are no obstructions or other works on the route to the construction site, and then Mammoet unload them.”
The BSTs will play a vital role storing intermediate‑level waste (ILW), including spent sand and ion‑exchange materials produced during the plant’s effluent treatment process which removes radioactive substances from liquid waste streams from across the Sellafield site before the treated water is safely discharged to sea.
