June 26, 2023, Büyükeceli, Turkiye. – Fifth tier of the, one of the key components of the nuclear power plant's safety system that protects and provides leak-tightness of the reactor compartment, was installed at Akkuyu NPP Unit 2.
The internal containment consists of steel lining and a special concrete mix that is produced directly at the Akkuyu NPP construction site. The fifth tier is a transitional component between the cylindrical and dome parts of the containment. Twelve steel sections were pre-welded together into a single ring-shaped structure weighing 129 tons. Then, using the world's most powerful crawler crane, the tier was installed to the design elevation in the reactor building.
AKKUYU NUCLEAR JSC First Deputy Chief Executive Officer, Director of Akkuyu NPP under Construction Sergei Butсkikh commented on the completion of the installation: "The installation of the fifth tier is a technologically complex process which requires careful preparation with many conditions considered. The fifth tier connects the cylindrical and dome parts of the internal containment. Many years of our experience in construction enable to save time assembling and installing containment modules. The installation of the fifth tier took only two hours. The height of Unit 2 has now increased by 6.5 meters to reach the elevation of 43.1 meters".
Concurrently with the construction of the internal containment, the erection of the outer and internal walls of the reactor building continues; the installation of the embedded parts of the equipment, personnel and standby air locks is in progress. 
For reference:
Akkuyu NPP is the first-ever nuclear power plant in Turkiye. The Akkuyu NPP project includes four power units equipped with Generation 3+ WWER reactors of Russian design. The capacity of each NPP power unit will be 1200 MW. 
Akkuyu NPP is the first project in the global nuclear industry being implemented according to the Build-Own-Operate model.
The Akkuyu NPP power units are equipped with modern and high-tech VVER-1200 reactor plants, which take into account the safety experience of many nuclear power plants. Reactors of this type have a double containment: an internal containment and an outer containment. The outer containment is formed of reinforced concrete and is capable of withstanding any extreme external impacts – earthquakes up to magnitude 9, tsunamis, hurricanes, as well as their combinations.
According to the terms and conditions of the Inter-Governmental Agreement between the Russian Federation and the Republic of Turkiye, the NPP's first power unit is supposed to be commissioned within 7 years after obtaining all construction authorizations. Given that the construction license for the Unit No. 1 was obtained in 2018, the deadline is 2025. At the same time, the project stakeholders are making their best efforts to ensure the readiness for start-up and adjustment works on the Unit No. 1 in 2023, a jubilee year for the Republic of Turkey.

Source: AKKUYU NUCLEAR JSC Communications Service