RDS-2 - Wikipedia
en.wikipedia.org › wiki › RDS-2The RDS-2 (Russian: РДС-2) was the second atomic bomb developed by the Soviet Union as an improved version of the RDS-1. It included new explosive lenses along with a new core design to decrease the probability of pre-detonation or 'fizzle'. [1] The RDS-2 weighed approximately 3200 kg and had a diameter of 1.25 m.