14 December 2020, Büyükeceli, Mersin Province, Turkey - Installation of the core catcher vessel into design position has been completed in the Reactor Building of Power Unit 2 of the Akkuyu NPP.
The height of the core catcher shell is 5.8 metres, diameter - 6.1 metres, weight – 169 tonnes. The vessel being the main part of the core catcher is a tank, which, in case of an emergency, will securely hold core melt within the sealed volume of the Reactor Building and prevent it from leaking in the environment. It is partially filled with a special material, which allows to stop chain reaction immediately and keep core melt stable.
The First Deputy Chief Executive Officer - the Director of the NPP under construction Sergei Butсkikh made the following statement upon completion of the core catcher vessel installation: "Core catcher is a unique development of Russian nuclear engineers, the key component of the passive safety system of a nuclear power unit. First the core catcher vessel was installed into design position, then the installation process was completed with precise control of the vessel position on the reactor cavity bottom. The installation was completed within the timeframe provided by the Akkuyu NPP construction schedule. Further, the so-called filler will be installed in the vessel. Core barrel will be erected around the core catcher vessel, upon completion of concreting of which we will proceed to install cantilever truss".
The next important stage in construction of Unit 2 reactor building will be installation of the first tier of inner containment into design position.
Cantilever truss shall provide protection of core catcher vessel and communications in hypothetical case of core melt-down. It is also designed for arrangement of communication lines - water supply, steam discharge, pass-through of communications for measurement instrumentation. Cantilever truss structure also provides special corridors for "catcher" inspection.
By virtue of the core catcher Akkuyu NPP shall be protected from any severe accidents. Previously, a similar "core catcher" has been installed at Akkuyu NPP Unit 1. These devices are used in modern nuclear power plants of Russian design with generation "3+" VVER-1200 nuclear reactors. The core catcher has maximum safety characteristics: increased seismic resistance, hydrodynamic and shock strength, flood protection and simplified installation technology.