There is some confusion over the RDS-2 nomenclature. Some accounts report that the nuclear bomb on highly enriched uranium-235 was tested at the Semipalatinsk test site in 1951. It was almost twice as light as the first (plutonium) bomb, but twice as powerful. The bomb was originally designed in the design offices of Arzamas-16 (Sarov) it was supposed to be a copy of the "Little Boy", but later it was decided to focus on a better version of implosion. In the core of the bomb used 239 Pu.
After testing the first atomic bomb RDS-1, the efforts of developers were focused on improving the design of the charge and its technical characteristics. The implosion principle was improved in the direction of decreasing the mass of the charge and increasing its power. The main contribution to the development of the idea of increasing the effectiveness of implosion and its implementation was made by L.V. Altshuler, E.I. Zababakhin, Ya.B. Zeldovich, K.K. Krupnikov.
The following tests of atomic charges after RDS-1 were carried out only in the second half of 1951. The design of atomic charge was given the designations RDS-2 , RDS-3 ( they differed only in the composition of the nuclear filling). The decision to create improved versions of atomic bombs was adopted by the USSR Council of Ministers in June 1948 and was confirmed after the RDS-1 test. This decision and the appearance of the first modifications of the RDS were apparently influenced, apparently, by the information communicated by Klaus Fuchs in 1948 in London. This information was associated with ideas for strengthening implosion and the sharing of various fissile materials. One of them was the idea of ??a shell-nuclear configuration of the central part, in which the active core is located in the cavity of the main shell, accelerated by the implosion process. In the United States, this idea is called the principle of levitation.
Levitating nuclei began to be considered in the designs of the United States from July 1945, and the first charge test using levitation was scheduled for the summer of 1946. Fissile material is usually suspended inside the tempera by means of a wire (spokes or stretching) so as not to introduce significant perturbations into the implosion process.
The technique of levitation allowed the transfer of as much energy as possible to compress fissile materials and thereby increase energy release. The very method of explosive acceleration of the mass of the material after the impact of another mass on it was well known even during the Second World War. He allowed several times to increase the intensity of the shock wave. This high-speed impact resulted in a better compression of the fissioning nucleus. The fact that this scheme was not used in the first nuclear warheads of 1945 was determined by the desire to reduce the risk during the first tests (one of the risk factors was considered possible perturbation of the symmetry of implosion) .
The RDS-2 was a second generation implosion atomic bomb based on Plutonium 239, developed for the heavy strategic bombers Tu-4 and Tu-16. Period of operation - the beginning of the 1950s. Weight was about 3100 kg. The test with the RDS-2 was performed on the Semipalatinsk test site at the P-1 experimental field site at the same site where RDS-1 was flown two years earlier. This site was completely restored for the new test.
On the morning of September 24, 1951 in about 1.5 minutes before the detonation of the cargo, in a strictly calculated time, on the place of the test, at an altitude of 10 kilometers flew a Tu-4 bomber, which gave a radio signal to the command post to activate the machine. The explosive power was 38 kilotons, which is approximately 1.9-2 greater than the explosion of the RDS-1. The flash of the explosion was observed at a distance of 170 km from the epicenter of the explosion, the sound of an explosion was heard. This was the second nuclear test because of the USSR. The pump was put into production, but not in service. Also RDS-2 was used in the Totski exercises, dropping it from the Tu-4 and with a detonation at an altitude of 350 m.
In the new bomb, a number of new design and technical solutions were developed, and its power compared to RDS-1 was almost doubled. The nuclear charge was already in the hull of the air bomb this time, as in the first case, was installed on a 37-meter tower, but the signal for switching on the submachine-gun was supplied from the Tu-4 bomber flying at an altitude of 10 km.
These tests showed that the application of the principle of levitation allows approximately two-fold increase in the efficiency of the use of fissile materials, and the use of a composite scheme allows to substantially save plutonium with equal energy release. These findings were similar to those that were made in the US three years earlier by the results of the Sandstone operation tests.
It should be noted that the principle of levitation, as noted above, provides very diverse possibilities for the choice of configurations for the placement of fissile materials in nuclear charges, and many of them have been in demand and practically implemented over time. In this regard, he had a profound and effective influence on the development of the nuclear program of the USSR.
In the designs of RDS-2 and RDS-3, one of the main geometric parameters of the RDS-1 charge was retained - the outer radius of the main spherical charge of explosives and the explosive composition - a mixture of TNT and hexogen in the ratio 1: 1 - TG 50/50. Investigations of gas-dynamic processes and the development of explosive charge elements were carried out by groups of scientists and experimenters under the direction of VK. Bobolev, A.D. Zakharenkova, G.A. Tsyrkova. One of the main tasks of these studies was to determine the optimal parameters (radius , mass, thickness) of the charge layers. Numerical solution of this problem was carried out in the mathematical institute. Steklov Academy of Sciences of the USSR under the leadership of K.A. Semendyaeva.
The focusing system RDS-2 and RDS-3 was fundamentally different from the focusing system used in RDS-1. It succeeded in eliminating the drawback caused by the principle of operation of the focusing element on the difference in the speeds of the explosives used, which made it possible to significantly reduce the height and mass of the focusing layer. The design of the RDS-2 and RDS-3 atomic charges, as well as RDS-1 , for security purposes, provided for the final assembly, connected with the installation of fissile material assemblies through the channel in the charge with the help of mounting hardware and the appropriate control instrument. This operation was carried out on the ground just before the explosion of charges.
Structurally, the channel was made as follows. In the spherical charge there was a through conical hole, which in the working state of the charge was closed by a corresponding conical stopper. The outer charge shell surrounding the charge of the explosive and the focusing system and the cascade of the inner shells of the central part had corresponding dimensions of the hatches located along the axis of the plug BB and closed with covers or plugs of the same thickness and the same material as the casings themselves. The technology of final charge assembly provided for a consistent installation and appropriate control of the nuclear filling and the component parts and assemblies of the assembly channel.
The RDS-2 and RDS-3 charges were successfully tested on September 24 and October 18, 1951, respectively. Their diameter and mass, in comparison with RDS-1 , decreased, and the power increased approximately twice. To initiate a chain reaction, a neutron fuse, similar to the RDS-1 fuse, located in the center of the charge, emitting neutrons when a shock wave was applied to it, was used in them.
In total, 59 RDS-2s were collected in the USSR. Part of the bombs RDS-2 was obtained by reworking RDS-1. Another RDS-2 atomic bomb was blown up on September 14, 1954 on the Totsky test area during tactical military exercises with the real use of nuclear weapons. During the exercises, a bomb with a capacity of 32 kt from a height of 8,000 m dropped a Tu-4 bomber. The bomb exploded at an altitude of 350 m with a deviation from the aiming point of 250 m.
|38 Kilotons (Plutonium 239)|
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