RBMK

The RBMK (Reaktor Bolshoy Moshchnosti Kanalniy, "High Power Channel-type Reactor") (Russian: Реактор Большой Мощности Канальный) is a class of graphite-moderated nuclear power reactor designed and built by the Soviet Union.

The RBMK is an early Generation II reactor and the oldest commercial reactor design still in wide operation; it features a number of design and safety flaws (such as graphite-tipped control rods, a dangerous positive void coefficient and instability at low power levels) that have since been rectified in newer designs. The reactor's flaws contributed to the 1986 Chernobyl disaster in which an RBMK exploded during an unsafe test and spread radioactivity over a large portion of Eastern Europe. The disaster prompted worldwide calls for the reactors to be completely decommissioned, although there is still considerable reliance on RBMK facilities for power in Russia and the post-Soviet republics; the last RBMK at Chernobyl was not shut down until 2000, and as of 2012 there were still at least 11 RBMK reactors operating in Russia.

Read more about RBMK:  History, Design Flaws and Safety Issues, Further Development, Closures, Status