The construction of the first industrial nuclear reactor started in the Southern Urals – its location was determined to be between the towns of Kasli and Kyshtym. There, at Base-10, Chelyabmetallurgstroy NKVD of the USSR built a plant and a settlement, which would later be called Chelyabinsk-40 and Ozersk, within the shortest time. On that memorable summer day in 1948, under the leadership and in the presence of the scientific leader of the Soviet nuclear project, Igor Vasilyevich Kurchatov, A-1 or “Annushka” – the first nuclear weapon reactor in the USSR and Europe – was put into operation. A year later the first Soviet atomic bomb, the RDS-1 that used Chelyabinsk plutonium, was successfully tested.