Reactor core and circulation circuit

The core is enclosed in the reactor cavity, formed by the top and bottom plates and a cylindrical barrel (KZh in Fig. 1) hermetically welded to the plates. 

Fuel assemblies installed in their channels consist of two subassemblies connected in series. The container type fuel rods are filled with pellets of low enrichment uranium dioxide with the addition of a burnable absorber (erbium). Fuel claddings are made of zirconium alloy (Zr 1% Nb), and channel tubes inside the core are fabricated from another zirconium alloy (Zr 2.5% Nb). Corrosion resistant steel is employed for the inlet and outlet pipelines of the channels outside the core. 

The circulation circuit of the reactor is divided into two loops, each including a group of the main circulation pumps (MCPs), the suction, pressure and distribution group headers (DGHs), drum separators, as well as the downcomers between the drum separators and the MCP suction header. Each of the two circuit loops has half of the fuel channels connected to it. 

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