At the Akkuyu NPP construction site, the installation of the reactor pressure vessel of the 1st power unit, which is one of the main stages of the assembly of the main equipment, has been completed. In the 1st power unit, the assembly of the core holder was completed, the supporting and bearing beams were concreted, and the dry armoring and thermal insulation works of the cylindrical part of the reactor vessel were completed. Just prior to the completion of the reactor vessel's installation, a supporting ring was mounted to support the vessel's main weight load.
This assembly process required special preparation of the field paths to move the reactor vessel within the radius of the 1st power unit. For this purpose, filling and leveling operations were carried out on the roads along the route. The special wheeled platform carrying the reactor vessel passed smoothly from the temporary storage area to the construction site of the 1st power unit after these operations.
The reactor vessel, which has a weight of 330 tons, a diameter of 4.5 meters and a height of 12 meters, was moved from horizontal to vertical using a Liebherr LR 3 type mobile crawler crane with a lifting capacity of up to 13000 thousand tons. After the equipment was placed in a vertical position, it was lifted above the reactor chamber and placed in its place in the reactor shaft.
Making a statement on the subject, AKKUYU NÜKLEER A.Ş. Sergei Butckikh, First Deputy Director General and Director of NGS Construction, said, “The assembly of the reactor vessel of the first power unit is one of the most important works on the field this year. The mounting of the supporting ring, on which the reactor vessel was installed, was done on 21 April. This is an element of the reactor plant construction designed to fix the vessel and prevent its horizontal and vertical movements when subjected to loads. The reactor vessel has now been moved to its designed position. I would like to draw attention to the flawless work of the assembly crew and lifting equipment operators. Installation of the container requires almost surgical precision, since the maximum permissible horizontal deviation does not exceed one-tenth of a millimeter. "Completing the installation of the reactor vessel will allow us to continue work on the construction of the reactor shaft," he said.
The assembly process was followed by the Nuclear Regulatory Authority (NDK), the French engineering group Assystem, an independent building inspection body, OKB “Gidropress”, the designer of the reactor facility at Akkuyu NPP, and AEM-Technology, the manufacturer of the reactor pressure vessel. scrutinized by its representatives.
The assembly of the reactor vessel was carried out using Open Top technology, which envisages installation from the open top of the cylindrical part of the reactor building. This technology, which has successfully proven itself in many projects related to the construction of nuclear power plants in China, Japan, Bulgaria and Russia, including the construction of the power units of the Leningrad NGS-1200 with a VVER-2 reactor, allows the construction and assembly to be carried out simultaneously and in an optimal way. It offers the opportunity to start the assembly of equipment and pipelines before the concrete pouring process on the floors is completed. The assembly of steam generators, pressure compensators, main circulation pumps and other main technological equipment in reactor buildings in Akkuyu NPP power units is also planned using Open Top technology.
Akkuyu NPP site workers will continue to pour concrete into the reactor shaft after the reactor vessel is assembled. Employees will also install supports for components of the main circulation pipeline and steam generators. After the installation of the steam generators and the vessels of the main circulation pumping unit, the welding work of the main circulation pipeline connecting the main equipment of the first cycle of the NPP can be started.
The reactor vessel of the 1st power unit was transported to the Akkuyu NPP construction site by sea in November 2020. The reactor vessel was transported to the site for storage after the vessel that brought it was unloaded at the Eastern Cargo Terminal, and had undergone an access control procedure there that verified the vessel's integrity and high quality fabrication.