On October 18, 1951, at the Semipalatinsk test site, a probable discharge of an atomic bomb RDS-3 with a capacity of 42 kilotons was carried out for a conventional purpose. This was the first real dropping of an atomic bomb from the bomber in the USSR. Tests showed that when an aerial explosion at an altitude of several hundred meters, the level of radioactive contamination of the terrain is more than 100 times less than when ground-based.
The peculiarity and difference of RDS-3 from previous models was the use of a combined core filling in the ratio 1: 3 (25% of plutonium to 75% of uranium), which allowed to save scarce plutonium and increase the number of atomic bombs produced in the Soviet Union.
RDS-3, also known as "Mariya", is the code name of a nuclear warhead created by the Soviet Union. It was the third nuclear device tested by the Soviets. The first experiment was conducted on October 18, 1951, at the Semipalatinsk Test Site. The RDS-3 was a nuclear device of intensified fission of implosion type, which had a composite nuclear levitating charge, with a "heart" of plutonium-239 and a "helmet" or "shell" of uranium-235. The design was realized from the experience obtained from the test of the RDS-1 on August 29, 1949 together with the RDS-2, of which it differed only in the composition of the nuclear charge. Both devices used the levitating charge design.
The RDS-3 pump was developed in the early 50's in KB Arzamas-16 simultaneously with atomic bombs type: RDS-2, RDS-4 and RDS-5. Its design is similar to the RDS-2, except for one important difference - the filling core is combined consists of 239 Pu and 235 U in the ratio of 1: 3 (25% plutonium and 75% uranium), in contrast to the RDS-2 that was totally plutonium. The idea of the combined filling was proposed after the shortage of plutonium and enough uranium-235. But the idea was initially skeptical because the arguments summed up in the fact that the state of critical mass of uranium-235 is much higher than that of plutonium-239, which in turn could lead to incomplete or blasting, not provoke a chain reaction of fission. Against this idea, Yu B. Chariton and Y. Zeldovich argued. However, the theoretical calculations E. Zababakhin and DA Frank-Kamenetsky showed that the gas-dynamic characteristics of a new cargo design created all the necessary conditions for a chain reaction. The RDS-3 test load showed important opportunities for scarce plutonium savings for the development of new nuclear weapons models.
One of the fundamental questions that have arisen before the tests was the question of how to test: on a tower like RDS-1 , or by dropping a bomb from an airplane? At the meeting of the scientific and technical council, where the issue of testing at the Semipalatinsk test site was discussed, opinions were divided. The developers of charges led by Yu.B. Khariton believed that the tests should be carried out on the tower (similar to RDS-1) , in order to more accurately determine the power and obtain more reliable information on the development of the chain reaction.
The leaders of the atomic project, headed by I.V. Kurchatov voted for conducting flight tests of the atomic bomb with bombing it from the aircraft for the purpose. In this case, in addition to determining the effectiveness of the explosion, the first time in the USSR would be a test of a combat atomic bomb. The final decision was transferred to the First Main Directorate. At this level, they decided to conduct a combat test with the bombing of a TU-4 aircraft.
However, as a result of further discussions, a "solomon solution" was adopted: RDS-2 with a plutonium fill is tested on the tower, and RDS-3 with a combined nuclear filling is bombed from the aircraft. This is what happened : RDS-2 was blown up on a tower 30 m high (E = 38 kt) , RDS-3 was dropped on the target from a height of 10 km and blown up at an altitude of 400 m above ground level (E = 42 kt) . Thus, on October 18, 1951, an atomic bomb was first tested in the USSR by bombing against a target.
The principal differences between RDS-2 and RDS-3 from RDS-1 , incorporated in the scheme and design of charges, formed the basis for the development of domestic nuclear weapons. Nuclear munitions RDS-2 and RDS-3 were transferred to mass production.
Bomb RDS-3 was dropped from a Tu-4 bomber from a height of 380 m, the energy was 42 kilotons. As shown by the studies of the atmosphere and the soil, as well as the sampling of the trajectory of movement of the clouds, the air after the explosion of radioactivity was 109 times less than that of terrestrial explosion. It was the first air and third nuclear test in the USSR.
|42 kilotons (25% Plutonium and 75% Uranium 235)|
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