RDS-4

RDS-4 was a Soviet nuclear bomb that was first tested at Semipalatinsk Test Site, on August 23, 1953. The device weighed approximately. The device was approximately one-third the size of the RDS-3. The bomb was dropped from an IL-28 aircraft at an altitude of and exploded at, with a yield of 28 kt.
The Soviet Union's first mass-produced tactical [nuclear weapon] was based on the RDS-4 and remained in service until 1966.It used a composite core of Pu-239 and 90% enriched U-235 and had a nominal yield of 30 kilotons. RDS-4 "Tatyana" turned out to be very compact - its weight and dimensions were four times less than that of RDS-1, which allowed the new bomb to be taken into service not only by long-range aviation, but also front-line. A tactical weapon based on the RDS-4 was also used on September 14, 1954 during Snowball military exercise at the Totsky range, when the bomb was dropped by the Tu-4 bomber. The purpose of this exercise was not to test the bomb itself, but the ability of using it while breaking through enemy defenses. After the explosion Soviet jet fighters were sent to fly through the mushroom cloud while tanks and infantry were forced to move through ground zero.