July 1, 2020, Büyükeceli, Mersin Province, Turkey. - The installation of the second tier of the reactor building's internal containment has been completed at the Power Unit 1 of Akkuyu NPP. Internal containment is one of the critical components of power unit's safety systems, which prevent release of radioactive materials to the environment.
"The installation of the containment's second tier brings us one step closer to the completion of construction of the Power Unit 1" - said Sergei Butskikh, the first deputy CEO and director of the NPP construction. "The containment's second tier is one of the largest structural components of the reactor building, and for that reason successful completion of its lifting and installation is a very important milestone for us. At the next stage the installed structure will be additionally reinforced, followed by formwork installation, and then we will proceed with concrete pouring ".
After the installation work performed by using Liebherr LR 13000 crane the height of the reactor building increased in by 12-meters, from the level of +4.95 meters to +16.95 meters. The total weight of the installed structure is 411 tons and its diameter exceeds 20 meters. The internal containment will comprise three tiers and dome. Once the installation of the internal containment is completed, it will undergo to pressurized leakage test.
In addition to the reactor building's internal containment, the construction project for the innovative Russian power units equipped with Generation III+ VVER-1200 reactors includes external containment. It is required to protect the reactor, steam generators and other equipment from extreme external hazards. 
For reference:
The double containment of the reactor building is a feature of the innovative power units of Russian design based on Gen III+ VVER-1200 reactors, a backbone of the Akkuyu NPP Project. Such sealed containment structure is highly reliable and is a new step towards the improvement of safety of nuclear power plants. The Russian-designed power units equipped with VVER-1200 reactors are being constructed not only in Turkey, but also in other countries including Belarus, China, Egypt, etc. Important to note that three power units equipped with VVER-1200 reactors are being successfully operated in Russia. 
Source: Press Service of AKKUYU NUCLEAR JSC