The Soviet Union claimed their RBMK reactor — developed by the secretive Ministry of Medium Machine Building — was unmatched in both productivity and safety. By 1986, the Chernobyl Nuclear Power Plant operated four, with two more on the way. But behind this veneer of success and prosperity lurked a dangerous secret. The Ministry knew the RBMK had already caused one near catastrophe, and the drive for more power would soon lead to nuclear catastrophe.