Rosatom has installed the main circulation pumping units (GTsNA (Glavnikh Tsirkulyatsionnikh Nasosnikh Agregatov)) in the reactor compartment of unit 2 at the Akkuyu NPP under construction in Türkiye. GTsNA enable forced circulation of the coolant in the primary circuit through the active zone of the reactor.
The last of the four spherical components was mounted in position using a self-propelled caterpillar crane. Installation of equipment was carried out using Open Top technology, whereby equipment is delivered through the open top of the cylindrical part of the reactor building. Before installation, the equipment was delivered from the warehouse to a special site next to the reactor unit building, where specialists enlarged the unit by connecting it to the lower spacer, the suspension element, and the biological protection ring.
“Having completed the installation of the main circulation pumps, we have completed the installation of the main equipment of the unit 2 reactor,” said Sergey Butskikh, General Director of project company Akkuyu Nukleer. “The reactor vessel, steam generators, and hydraulic components of the safety systems are already in place, and soon we will begin welding the main circulation pipeline to connect all these components.”
The GTsNA is a first-class safety product. This means that the strictest requirements are placed on the quality of its manufacture. During the operation of the NPP it will operate at a pressure of about 160 atmospheres and at a temperature of 300 degrees, circulating the coolant in the primary circuit. The equipment for VVER-1200 reactor units includes four GTsNAs.
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 expected to begin operation in 2025. In July 2024 Akkuyu NPP reported that some 70% of the equipment and systems installed at unit 1 had already undergone commissioning.
Meanwhile, Russia’s Atommash plant (part Rosatom’s Engineering Division) has completed a key stage in the manufacture of the nuclear reactor vessel for Akkuyu unit 4, completing the closing weld, which connects the individual parts of the product into a single VVER–1200 reactor vessel. This stage of the work is considered one of the most time-consuming.
Welding lasted for 10 days with continuous heating of the seam area in the range from 170-280 degrees Celsius. More than 1.2 tonnes of flux and tonnes of wire were consumed. After welding, the reactor vessel will undergo a heat treatment process, and then the full range of control measures will be carried out in the weld areas: X-ray flaw detection, ultrasound and capillary controls. The quality of the welded joints of reactor equipment is a critically important factor ensuring the safety and reliability of NPP operation for at least 60 years.
“The completion of welding of the Akkuyu 4 reactor vessel indicates that Atommash has completed one of the most labour-intensive and long-cycle operations for the manufacture of reactor equipment for Türkiye’s first NPP,” said Maxim Zhidkov, head of the Atommash plant. “The plant manufactures a wide range of equipment for the nuclear island and the engine room for the project: internal devices, steam generators, pipe system modules, passive reactor protection systems, pressure compensators. A total of 8,000 tonnes of equipment were produced. And this figure will grow to 11,000 tonnes,”.
To increase the reliability and efficiency of NPP operation, the enterprises of Rosatom’s Mechanical Engineering Division continuously improves structural materials and welding technologies, increasing radiation resistance and reducing the number of welds required. This has already made it possible to increase the service life of generation 3+ reactors to 60-80 years. In the future, the use of new materials will make it possible to increase this further to 100 years.
