It was in Kyshtym, just outside Mayak in the Ural Mountains region. The Mayak plant was built in haste between 1945 and 1948 and Soviet scantiest then knew little about nuclear technology back then! The Kyshtym (Urals Mountains) disaster is known by several names including East-Ural Radioactive Trace, Kyshtym disaster, Urals Mountains disaster, Mayak disaster and the 1957 Soviet atomic disaster.