In the 1st power unit of the Akkuyu Nuclear Power Plant (NGS), the third layer of the reactor section interior protection building was installed. It took about one day to assemble the cylindrical structure, which weighs 322 tons.
The third layer of the interior protection building, a welded metal structure, consists of 11,5 sections, each 5,8 m high, 13,4 m wide and weighing 24 tons. The sections were combined into a single block with a circle length of 138 meters. The assembly process of the structure was carried out next to the reactor section of the 1st power unit. Upon completion of assembly, the quality of all welded joints was ultrasonically tested.
The assembly of the third layer of the interior protection building was carried out by one of the most powerful crawler cranes in the world, using a specially developed technology that requires the preservation of geometric parameters during installation. The allowable deviation from the specified diameter did not exceed 5 mm.
After the installation of the third layer, the height of the reactor building increased by 11.6 meters and reached +28.55 meters. With the completion of this stage, the experts will begin the process of combining the second and third layers, strengthening and concreting the protection building. After pouring the concrete, the walls will be 1,2 meters thick. The interior protection building will consist of a total of 4 layers and 1 dome. The building will also undergo a leak test after the assembly of all its components is completed.
Making a statement on the subject, AKKUYU NÜKLEER A.Ş. Sergei Butckikh, First Deputy Director General and Director of NGS Construction, said: “Just a week ago, we installed the reactor pressure vessel of the first power unit and have now passed another important phase of construction. The third tier of the interior protection building was installed at its projected location. We had a good pace in terms of completing the main construction phases. The next switch installations will take place on the 2nd power unit this summer. These will include the installation of the reinforced concrete beam of the reactor shaft, the second layer of the interior containment building and the support beam. We have completed the concreting of the turbine building foundation plate in the 3rd unit and the foundation plate of the reactor building will be ready soon.”
The reactor buildings of the Akkuyu NPP project will be equipped with two-layer protection buildings. The outer protection building, made of reinforced concrete, was designed to withstand all kinds of extraordinary external effects. The interior protection building, on the other hand, is made of special concrete with a steel coating that ensures the sealing of the reactor section. The internal protection building, which is a safety system that localizes the nuclear power plant, not only ensures the stability of the reactor compartment, but also serves as a pole crane support where nuclear reactor maintenance operations are carried out during the pipelines and NPP operation phase.