To the reaction was more efficient, neutrons must be slowed down, or they just "fly away" from the active region. For this purpose, rods moderator (graphite) that are inserted into the reactor – sometimes (as at Chernobyl), a graphite reactor itself is masonry. There in the reactor and the other rods. First, this protection and control rods are designed to attenuate the course of the reaction, if it goes too heavily and in danger of overheating of the reactor, or vice versa, "let go" of her. To do this protection rods are inserted deeper into the channels reactor or removed from it – it can happen in an automatic, or "manual" control mode. These cores are composed of boron, which absorbs neutrons very well and is able to quickly stop the nuclear chain reaction. Second, it bars that serve as fuel cells: they were heated, turning water into steam, cooling themselves with it.
These rods are a complex combination of zirconium and uranium. Chernobyl worked on power reactors of the RBMK-1000 ("high-power channel reactor of 1,000 MW.") Actually, everything above happens in the so-called the reactor core, the rest of it – a water-filled steel tank, protective plates and additional screens – designed for safety. Unit itself, in addition, includes a circulating pump supplying water to the reactor bottom. On top of it leaves a powerful jet of steam-water mixture which separates into steam and water drum-separators. Only now clear (and very hot) steam enters the turbine. Pairs, which thus resulted in rotation of the generator rotor is not removed from the system.