Joe 4/RDS-6s
1953 - Semipalatinsk, Kazakhstan
On August 12, 1953, the USSR conducted its first thermonuclear test at the Semipalatinsk test site. The weapon used a design known as the "Sloika" model in which fission and fusion fuel were "layered". The total yield was 400 Kt and 15-20% of the energy was released by fusion.
Yield: 400 Kilotons
Location: Semipalatinsk, Kazakhstan
Date: August 12, 1953