At unit 3 of the Akkuyu NPP under construction in Türkiye, the fifth tier of the internal containment shell VZO – Vnutrennei Zatsitnoi Obolochki) has been installed. The ring-shaped welded metal structure weighing 396 tonnes and 6.5 metres high, was assembled at a special site next to unit 3 and was moved to its regular location by a crawler crane.
The fifth tier is a connecting element between the cylindrical and dome parts of the containment shell. It consists of 12 reinforced concrete blocks (sections). The blocks began to be put together long before the installation operation. They were joined and welded together into a single ring structure weighing about 115 tonnes. Then special consoles were welded to the reinforced concrete blocks, on which a rail track was installed for the operation of a circular overhead crane (polar crane). As a result, the weight of the structure increased to 396 tonnes. The hook suspension of the crane weighed another 50 tonnes – a mechanism for reliably hanging a load on a hook. The total weight of the cargo moved by the crawler crane was almost 450 tonnes.
“We completed the enlarged assembly of the fifth tier of the containment shell at the end of 2023,” said Sergei Butskikh, General Director of project company Akkuyu Nukleer. “The installation of the consoles to which the polar crane track is attached is usually carried out at height, after the tier has been installed. In order to optimise the timing of further construction and installation work, we decided to mount the consoles while the tier was still on the ground, and then mount the already assembled structure in the design position. Russian and Turkish specialists – installers, crane operators, slingers – again demonstrated the highest level of professional skill and successfully installed a multi-ton structure.”
Akkuyu, Türkiye’s first NPP, will eventually host four Russian-designed VVER-1200 reactors. The pouring of first concrete for unit 1 took place in April 2018, for unit 2 in June 2020, for unit 3 in March 2021, and for unit 4 in July 2022. Rosatom is constructing the reactors according to a build-own-operate model. Unit 1 is expected to begin operation in 2025. In July Akkuyu NPP reported that some 70% of the equipment and systems installed at unit 1 had already undergone commissioning.
