1 March 2021, Büyükeceli, Mersin Province, Turkey. The cantilever truss, second large-sized structure of the core catcher is installed in the reactor building of Akkuyu NPP Unit 2.


The structure made of carbon steel with the mass of 176 tons, the diameter of 9.35 m and the height of 2.2 m was installed in the design location under the reactor shaft of the Power Unit 2 using the Terex Demag CC6800 crawler crane located between the construction sites of the Akkuyu NPP Units 2 and 3. The installation was preceded by the assembly of the cantilever truss on a special jig, which took about a month and a half.


The installation of the cantilever truss was commented on by the First Deputy General Director - Director of the Akkuyu NPP under construction Sergei Butсkikh: “Core catcher device consists of three parts: the vessel, cantilever truss and guide plate. Earlier, in December 2020, the vessel of core catcher was installed at the bottom of the reactor shaft, over which the cantilever truss is now mounted to protect the vessel and communications of the core catcher. This complex engineering facility is an important component of the plant's safety system, one of several components ensuring the reactor meets the most advanced international safety requirements. The installation of the cantilever truss is the first milestone we have completed this year”.


Acceptance of the cantilever truss installation works was carried out by a special commission, whose members performed visual, measuring and other types of control and confirmed the readiness of the structure for the subsequent operations. Later on nozzless and operating galleries will be welded to the truss in the assembly process. Then the assembly and concreting of the dry shielding, the assembly of the supporting truss will be started, and the construction of the reactor shaft will be continued. AKKUYU NUCLEAR JSC young specialists, graduates of NRNU MEPhI, leading specialist in physical calculations of the nuclear safety unit Abdullah Safa Duman and leading specialist in accounting and control of nuclear material Ebru Adıgüzel were involved in the work of the acceptance commission.


The primary purpose of the cantilever truss is to organize communications: water supply, vapour disposal, ventilation, arrangement of penetrations for measuring instrumentation and inspection of the core catcher device. Gas removal pipelines, which are installed in the truss, ensure the circulation of saturated vapour and do not allow the pressure in the reactor shaft to exceed the admissible values. The truss also serves as a support for the subsequent structural components - the guide plate and the reactor dry shielding.