Installation of the outer containment dome at Akkuyu NPP’s first unit completed

On 23 September 2024, the containment dome was successfully installed on the first reactor at Akkuyu NPP in Turkey’s Mersin Province. The dome is the final component of the reactor’s outer containment structure.

The dome is being built in several stages: manufacturing composite elements from layers of metal, installing them and then gradually pouring concrete.

The dome weighs 147.6 tonnes and has a diameter of 34.7 metres. It took 6 hours to install this heavy metal structure in its designed position, using the world’s most powerful self-propelled crawler crane. Thirty specialists from Akkuyu NPP took part in the installation. The containment is one of the physical barriers in the nuclear power plant’s multi-layered protection system.

Safety functions of the dome

The outer containment dome was positioned at a height of +57.1 to +65.4 metres above the building’s reference level. The robust steel structure can withstand extreme external impacts and combinations of them. The next step will be to encase the metal dome structure in high-strength concrete, with a wall thickness of 1.5 metres. The installation of the equipment for the heat removal system can then begin.

The outer containment is made of reinforced concrete and is designed to withstand earthquakes with an intensity of up to 9 on the MSK-64 scale, hurricanes with wind speeds of up to 60 m/s, tsunamis and subsequent waves up to 10 metres high.

VVER-1200 reactor

Modern Russian power units with VVER-1200 reactors are equipped with a double containment system (outer and inner), which ensures a high level of safety at the nuclear power plant and adds strength to the reactor building. In addition to the outer containment, there is also an inner containment, which ensures the reactor building is airtight and serves as a supporting structure for the pipes and the polar crane, used to maintain the nuclear reactor during the power plant’s operational phase.

Akkuyu NPP is the first nuclear power plant being built in Turkey. The Akkuyu NPP project comprises four power units equipped with Russian Generation III+ VVER reactors. Each unit will have an installed capacity of 1200 MWe. Akkuyu NPP is the first nuclear power plant project globally to be implemented under the Build-Own-Operate model.