Installation of the containment prestressing system (CPS) has been completed in the unit 1 reactor building at the Akkuyu NPP under construction in Türkiye. This provides additional strength to the concrete structures of the reactor building by prestressing bundles of steel ropes. The CPS is an important component of the containment safety system, which is designed for extreme loads and their combinations. The containment can withstand an internal pressure of 5 kg/cm2 and external impact of a shock wave creating a pressure of 30 kPa and crash of a large aircraft.
“The prestressing system increases the safety, stability, and manufacturability of the reactor building and the NPP as a whole,” said Sergei Butskikh, First Deputy General Director of project company Akkuyu Nukleer and Director of NPP construction. “These works are particularly difficult and are executed in compliance with all technical requirements. Akkuyu NPP specialists are starting to conduct acceptance tests of all components to determine their strength. The containment prestressing system will be checked for tightness and density.”
Construction and installation work on the CPS took place from the very beginning of the construction of the reactor building. The installation of support cups and channelisers, acting as void formers, was carried out at the containment construction stage, in which high-strength reinforcing ropes were subsequently mounted and filled with a special cement mortar. Once the structure reached the design strength, the tensioning of 128 bundles of reinforcing ropes was performed. Of these, 68 were stretched horizontally and 60 stretched vertically. Hydraulic jacks were used to tighten the steel ropes. The tension force of each beam was equivalent to about a 1,200-tonne-force.
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.
