Fifth Tier of The Inner Compartment Shell Installed At Akkuyu NPP Unit No. 1

January 14, 2022, Büyükeceli, Mersin Province, Turkey. – The fifth tier of the inner compartment shell (ICS), one of the main safety system components, has been installed in the reactor compartment of Akkuyu NPP Unit No. 1. IC ensures protection of the reactor compartment and acts as support for pipeline penetrations and the polar crane, which is used to carry out nuclear reaction maintenance operations.

ICS is formed of steel liner that ensures the leak-tightness of the reactor compartment and special concrete. The fifth ICS tier is a welded metal structure comprising 12 sections. Firstly, 10.75-ton sections, which are 6.45 meter high, were welded to each other on a special platform and assembled into a single 129-ton ring of 44-meter diameter in its wide (lower) part. The ready-made ring was then lifted above the ground and installed into the design position in the reactor building using a heavy crane.

Sergei Butсkikh, AKKUYU NUCLEAR JSC First Deputy Chief Executive Officer and Director of the NPP under Construction, commented on the completion of the 5th ICS tier installation as follows: "The main installation difficulty was that the 5th tier is a transitional component between the containment's cylindrical and dome parts. A thorough preparation was carried out the day before the operation to take a huge number of conditions and parameters into a count, such as load weight, load movement distance, slinging diagram, weather conditions on the installation day and many other factors. Technical operation was completed successfully, and the load was moved to the installation place with 1-millimeter precision. At the next stage, construction workers will need to install 60 cantilevers which will service as support of the polar crane's rail track. It is an important structural component of the reactor building, and they will bear the main loads caused by large-size equipment and cargo being lifted by cranes."

Upon the fifth-tier installation, the height of the Unit No. 1's reactor building increased by almost 6.5 meters and reached 43.1-meter elevation.

Installation of the ICS tier is a time-consuming process operation. The fifth tier was installed into the design position using Liebherr LR 13000, a heavy caterpillar crane, which took about 12 hours.

Alongside the inner containment construction, construction works on outer and inner walls, as well as installation of embedded parts of equipment, personnel and back-up airlocks are in progress in the reactor building. The first-storey floors at 8.4-meter elevation, as well as walls and columns are being constructed in the turbine building.

Rector buildings of Akkuyu NPP Power Units are equipped with double containment. The external containment is built of reinforced concrete and designed in a way to withstand any extreme external impacts, such as earthquakes with magnitude of up 9, tsunami, hurricanes, and their combinations.

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