News

09.09.2020

REACTOR DRY SHIELDING INSTALLED AT AKKUYU NPP POWER UNIT 1

  Another milestone has been completed at the Akkuyu NPP construction site. The reactor pressure vessel dry shielding, a safety component providing reliable NPP operation in emergencies including earthquakes of intensity up to 9 points, has been installed at Unit 1. This component also provides for stable operation of the ionization chambers - the measurement channels, which are required for reactor power control.

 

The dry shielding surrounds the reactor pressure vessel and makes for a thick-walled, cylindrical steel structure filled with heat-resistant serpentine concrete which withstands high heat up to 500°С.

The dry shielding consists of two components, the upper and lower ones. They are welded leak-tight with one another and form a cylinder filled with concrete. The assembled structure is sent for drying at temperature of 220 degrees in order to remove excess moisture from the concrete. After drying the structure is checked for cracks inside the concrete. Neutron profiling is performed for this purpose: neutron flux is input from one side of the cylinder, and a sensor records their intensity on the outside. The examination of dry shielding for the Akkuyu NPP Unit 1 confirmed the high quality of the placed concrete.

 

The dry shielding weighing 142 tons, more than 6.5 m of outer diameter of and more than 5 meters high was installed using a special cross arm.

The dry shielding for Akkuyu NPP was manufactured by Tyazhmash plant (Syzran, Russia). On the previous day, August 26, Tyazhmash delivered another crucial safety component for the power unit No. Corium Collecting and Cooling Device ("core melt trap").