The RDS-1 was the Soviet Union's first nuclear weapon test. In the west, it was code-named Joe-1, in reference to Joseph Stalin. It was test-exploded on 29 August 1949, at Semipalatinsk, Kazakh SSR, after a top-secret R&D project. The weapon was designed at the Kurchatov Institute—at the time officially known as "Laboratory № 2," but designated as the "office" or "base" in internal documents—starting in April 1946. A uranium-235 plant was built near Chelyabinsk in 1948. The RD… (More on Joe-1)