Cantilever truss, an important component of the core catcher (CC), has been installed beneath the reactor cavity in the reactor compartment of Akkuyu NPP Unit 3.
The structure is made of special carbon steel, weights 180 tons, has 9.5-m diameter, and is 2.3-m high. The cantilever's installation took one shift, while its pre-assembly took 17 days. Its service life is not less than 60 years.
The main designated use of the cantilever truss is arranging the following utilities: water supply, steam removal, ventilation, and equipment of passages for instrumentation and core catcher inspection. The gas removal pipelines, which are installed in the truss, ensure circulation of the saturated gas and prevent the pressure inside the reactor cavity from exceeding permissible values.
The cantilever truss also serves as support for subsequent structural components, namely guide plate and dry reactor shielding. During examinations or repair works in the reactor building, it will ensure the possibility of accessing the air supply header, cooling of dry shielding and guide plate, as well as access to the maintenance site through the CC.
"The cantilever truss has been installed within the deadlines established by the Construction Plan, and then the lower plate, another large component of the core catcher, will start. Works are being performed by experienced specialists in a regular mode. The same equipment was installed at the first and the second power units," commented Sergei Butckikh, First Deputy Chief Executive Officer – Director of the NPP under Construction.
Construction and installation works at the Akkuyu NPP Site are being performed in all construction areas of the main and auxiliary facilities, namely: four power units, on-shore hydraulic engineering structures, power output system, administrative buildings, training center and physical protection facilities of the future NPP. All construction stages are thoroughly monitored by independent inspection organizations and the Nuclear Regulatory Agency of Türkiye (NDK), the national regulatory authority.
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Akkuyu NPP is the first nuclear power plant being built in the Republic of Türkiye. The Akkuyu NPP project includes four power units equipped with Generation 3+ VVER reactors of Russian design. The capacity of each NPP power unit will be 1200 MW. Currently, the project is entirely financed by the Russian side. At the same time, Rosatom State Corporation is entitled to sell its stake in the project of up to 49% to other investors. Akkuyu NPP is the first project in the global nuclear industry being implemented in accordance with the Build-Own-Operate model. According to the terms and conditions of the Inter-Governmental Agreement between the Russian Federation and the Republic of Türkiye, the NPP's first power unit is supposed to be commissioned within 7 years after obtaining all unit-construction permits and licenses. Given that the construction license for Unit 1 was obtained in 2018, the deadline is 2025. At the same time, the project stakeholders are making their best efforts to achieve the milestone "Delivery of fresh nuclear fuel to the Akkuyu NPP Site" in 2023, when the 100th anniversary of the Republic of Türkiye is celebrated.