The inner containment dome has been placed in its
design position at Akkuyu NPP Unit 2 (being built by Rosatom in Türkiye). This operation marked one of the key events in the construction of the
reactor building, allowing the completion of the internal containment of the
power unit.
The dome was lifted using a heavy-duty crawler crane. From the start of the lift to the placement in the design position, the operation took approximately seven hours. Around 40 specialists were involved in the operation, handling rigging, securing, and balancing the load, as well as guiding and fixing the metal structure.
The inner containment dome has a hemispherical shape and consists of 15 assembly sections made of special structural steel. The pre-assembly of the dome near the power unit building took about four months. A special lifting beam, designed considering the dome's geometry and weight, was used for the lift.
"The installation of the inner containment dome is one of the most technically complex and critical operations in the construction of a reactor building. The construction and installation team prepares for it over several months. A great deal of work has been accomplished: the manufacturing and delivery of the inner containment sections to the site by road and sea, the pre-assembly of the structure, welding of its components, and preparation for the lift. The successful completion of this operation is the result of the efforts of hundreds of professionals – engineers, assemblers, welders, riggers, crane operators, and many others", Akkuyu Nuclear JSC Chief Executive Officer Sergei Butсkikh noted.
Following the installation, construction workers will perform welding of the dome and the cylindrical part of the inner containment, which will form the leak‑tight volume of the reactor compartment, and will continue reinforcement and concreting on the containment.
Reactor buildings of the Akkuyu NPP power units are
equipped with a double containment. The inner containment
consists of a steel lining, ensuring the leak-tightness of the reactor
compartment, and special concrete. The inner containment is the nuclear power
plant's localization safety system, ensuring the stability of the reactor
compartment and supporting pipeline penetrations and the polar crane. The outer
containment is made of reinforced concrete and is designed to withstand any
extreme external impacts.
The inner containment of the Akkuyu NPP reactor buildings is being installed stage by stage, in tiers. The first tier is assembled section by section directly within the reactor building. The second and subsequent tiers are assembled section by section near the building of the power unit under construction on special jigs (stands), and after that they are assembled within the reactor building using a heavy-duty crawler crane. The inner containments of the Akkuyu NPP reactor buildings consists of seven such tiers. The seventh tier (dome) of the inner containment weighs about 215 tons, and the total mass of the structure during the lift, including the welded service platforms for the current leads and sprinkler system, exceeds 250 tons. The securing, lifting, and movement of the load are carried out using a special spreader lifting weighing 66 tons which allows for high-precision adjustment of the position of the structure attached to the crane.
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 power unit is 1200 MW. Akkuyu NPP is the first project in the global nuclear industry being implemented according to the Build-Own-Operate business model.
