The foundation of the turbine unit has been concreted at unit 4 of the Akkuyu NPP under construction in in Türkiye. In preparation for concreting, specialists installed 308 tonnes of rebar, 69 tonnes of embedded parts, and installed anchoring equipment for fixing the turbine. The operation was carried out continuously for more than a day during which time the builders laid 2,241 cubic metres of concrete mix using nine concrete pumps.
Thick reinforcement, complex geometry of the foundation and a large number of embedded parts determined the technology of laying the mixture. Throughout the operation, the concrete plants at the Akkuyu NPP site ensured uninterrupted supply of the mixture, and the specialists involved in the work coordinated the pumps and the laying of concrete at different sites.
“For the project team, this is the fourth turbine unit foundation at the Akkuyu NPP. The reliability of the turbine unit is determined by the construction of its base,” said Sergey Butskikh, Director General of project company Akkuyu Nukleer. “The design must withstand not only the weight of the turbine and generator, but also the load from their operation. Special spring blocks reduce the transmission of vibrations to the machine room structures. The foundation will ensure reliable operation of the equipment, which will have to generate electricity for Turkey for decades.”
At the end of concreting, the foundation will develop its design strength over about 60 days. After that, the specialists will dismantle the formwork and carry out an inspection of the structure. The quality of the work will be checked by a commission with the participation of specialists from the Turkish Nuclear Regulatory Agency (NDK – Nükleer Düzenleme Kurumu) and an independent supervisory organisation. Following the inspections, work will begin on the installation of turbine components.
The foundation of the turbine unit is a massive reinforced concrete structure that takes on the weight of the turbine and generator, as well as distributes the loads that arise during their operation. The stable operation of the equipment largely depends on the strength of the base, the accuracy of its geometry and the location of fasteners. The design provides a vibration isolation system with special spring blocks. They reduce the transmission of vibrations from a working turbine unit to the building structures of the engine room and help to increase seismic resistance.
Akkuyu 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 currently preparing for commissioning.
