Leningrad

The RBMK-1000 is a water-cooled and graphite-moderated reactor that uses thermal neutrons. RBMK is an abbreviation of Reactor bolshoj moshchnostij kanalnij (high power channel reactor). It is thought to be the most unsafe in the world, both because of technical weaknesses and because the graphite in the reactor is combustible. The reactor is 7 metres high and has a diameter or 11.8 metres. Each reactor has 1,661 fuel assemblies that consist of 18 fuel pins with an enrichment of 2.4 percent 235U.