Strength and leak-tightness tests of the reactor
building containment have been successfully completed at Unit 1 of Akkuyu
Nuclear Power Plant (being built by Rosatom in Türkiye). Specialists verified
the structure’s ability to withstand the loads specified by the design and
maintain leak-tightness at possible raises of pressure at the off-nominal
situations.
The tests were carried out continuously over eight days. To verify the structure’s strength, the air pressure inside the containment was gradually increased to 0.46 MPa. This was 15% above the design pressure of 0.4 MPa, at which the structure’s leak-tightness was assessed. At peak pressure, the load on each square metre of the containment surface was equivalent to the weight of approximately 47 tons. Once the maximum pressure had been reached, it was also reduced in stages. Throughout the process, specialists monitored the condition of the containment, including stresses within the structure and changes in its shape and dimensions under load.
The programme included leak-tightness checks both at elevated pressure and at reduced pressure, below atmospheric pressure. The test results confirmed that the structure fully meets the design requirements for strength and leak-tightness and can withstand internal overpressure.
“A series of verification tests is being carried out consequently at Unit 1. Equipment, structural components and safety systems are being checked. We have successfully tested the main protective barrier of the unit. The results confirm the high quality of the containment construction work and enable us to move shortly to the next stage of pre-start-up commissioning: cold and hot functional testing of the reactor plant,” said Akkuyu Nuclear JSC Chief Executive Officer Sergei Butckikh.
Double layer containment is one of the design features
of power units with VVER-1200 reactors. The inner containment surrounds the main
reactor plant equipment and acts as a barrier preventing the release of
radioactive substances into the environment. Strength is provided by the
reinforced concrete structure with its prestressed tendons, while
leak-tightness is ensured by the internal steel liner. The outer containment is
made of reinforced concrete and is designed to withstand extreme external events,
including earthquakes with an intensity of up to 9, tsunamis, hurricanes and
combinations of these events.
Akkuyu NPP is the first nuclear power plant under construction in the Republic of Türkiye. The Akkuyu NPP project consists of four power units with Russian-designed VVER generation 3+ reactors. The capacity of each power unit will be 1,200 MW. Akkuyu NPP construction is the first project in the global nuclear industry implemented on the basis of the Build-Own-Operate business model.
