The Role Of Nuclear Weapons
The proposed design supposed the use of sub-critical pieces of Uranium-235, separated by Cadmium plates which were to be destroyed by conventional explosive at the moment of the device's "ignition". Simultaneously Maslov and Shpinel along with F.Lange presented to OI KA draft design of gas centrifuge, for which OI KA issued the Patent Number 6359s (which was also classified "Secret"). Along with Leningrad Physical-technical Institute KhFTI was the leading Soviet research center in the field of nuclear physics in the 1930s.
In November 1941 physicist Georgiy Flyorov wrote to the State Defense Committee (GKO) Sergey Kaftanov who supervised scientific researches in the military field with proposal to launch the atomic bomb project. Flyorov's background made him perfectly suited for such the proposal - he was one of the authors of the discovery of Uranium spontaneous fission (Konstantin Petrzhak was the another author) and discovered in collaboration with Leonid Rusinov that Uranium nuclei emitted more than two neutrons in an act of fission what was critically important for the possibility of sustained chain reaction in Uranium. Flyorov warned Kaftanov about the fact that the country which would be the first who obtain the Bomb would obtain through that possibility to dictate its will to the rest of the world. (16)
In a month (on December 21, 1941) Flyorov wrote one more letter with draft design of a fission explosive device of the gun-assembly type. (17) In April 1942 Flyorov wrote the letter with the same proposals directly to Stalin.
Regardless of all scientists proposals the Soviet leadership did not pay attention to the nuclear weapons development problem. But in early Spring 1942 the 56th Army reconnaissance team captured near Taganrog on the Azov Sea shore a Nazi officer's notebook with what turned to be calculations related with chain reaction in Uranium. (Supposedly that officer could be Werner Heizenberg's assistant - Echler - who was conscripted in late 1941 and was stated "lost in action" during the Spring 1942 campaign near Azov Sea.) (18)
The captured document was delivered to Kaftanov and that information about the German Uranium Project became the last drop which forced the Soviet leadership to take seriously all the voluminous intelligence information and Soviet scientists' warnings on importance of work in the field of nuclear bomb. In late 1942 the GKO ordered the Academy of Sciences to begin feasibility study in the field of military use of nuclear energy. (19) Next winter, on February 15, 1943 the GKO issued the order to establish the single research unit responsible for coordination of all researches in the military nuclear field. (20) So-called Laboratory No 2 headed by Professor Igor Kurchatov became that unit.
Meanwhile the nuclear weapons researches continued to stay low key for the Soviet leadership. The fact is illustrative that the Laboratory No 2 personnel numbered just 83 by end-April 1944 including only 25 scientists (21) - almost four-fold less than at weapons design-oriented American Los-Alamos at its very first days a year and a one-half a year before that. Even the U.S. Trinity test on July 16, 1945 did not change Stalin's leadership attitude towards the atomic bomb. After being informed (in indirect words) by President Truman about the United States obtaining the new extremely powerful weapon Stalin ordered to inform Kurchatov to speed the work up.
It was only the Hiroshima and Nagasaki bombardments which forced the Stalin's leadership to change its mood. One of the reasons for that change was that it turned impossible to hide the word about Hiroshima and Nagasaki from the Soviet people and that news gave birth to nervousness among the Soviet population. (22) It turned that General Groves was right when concerned about the low impression the [basically technical] Trinity test could have for the Soviet leaders and on that ground proposed the combat bombardment of real targets. Indeed, the information from the Soviet military observers invited by the U.S. authorities to visit Hiroshima and Nagasaki to evaluate the level of destructions produced by the August bombardment was met in the Kremlin with the great attention. (23)
In two weeks after Hiroshima - on August 20, 1945 - the GKO issued the resolution No 9887ss/op (classified "Top secret. Special File" - the highest level of classification in the Soviet practice) to establish the State Special Committee responsible for urgent launch of full-scale work aimed to development and production of Soviet nuclear weapons. That at last became the real beginning of the Soviet nuclear program. Late December the same year the Soviet of People's Commissars (SNK - the Soviet Government, in 1946 re-named into Council of Ministers) issued the resolution on establishment and urgent beginning of works on creation of the atomic industry. (24) And it was only February 1946 when the resolution to establish the Laboratory No 2 branch to design and manufacture a nuclear device per se - so-called Design Bureau No 11 (KB-11, later on the All-Union (now - All-Russian) Scientific-Research Institute of Experimental Physics (VNIIEF), widely known by the latest coded name of its location as Arzamas-16). At first the size of the KB-11's personnel was defined on the level of just 70 (seventy) scientists, engineers and workers. (25)
At that stage of the Soviet nuclear project the Soviet Union attempted hard to play down the importance of the role the nuclear weapons could have in the international relations. (26) The famous Molotov's statement of December 1947 that there was not any more the secret of atomic weapons for the Soviet Union was one of those attempts.
At the same time all efforts were aimed to producing the first nuclear device as quick as possible. All improvements of the "American" design were prohibited if they could postpone the test. (27) It was also officially ordered not to work upon original designs or their units but rapidly repeat the American one supplied by the spy sources and twice (in Alamogordo and Nagasaki) successfully tested to ensure high probability of success.
The latter was the reason for cancelation at that stage of the development work upon the RDS-2 ("Article 601") atomic device with Zababakhin's design of explosive lenses. The decision to stop the work upon the RDS-2 device was the more important that it provided the yield/weight ration three-fold higher than that of the Fat Man-type design. (The work upon RDS-2 was resumed in early 1950 after the successful test of the first nuclear device.)
In such the conditions the test of RDS-1 nuclear device which was the analog of the U.S. Fat Man-type device (not the exact copy - for instance, one of its the most critical component - "implosion belt" - consisted of 32 explosive segments instead of 96 as in the U.S. Fat Man) was prepared by Summer 1949. Regardless of a hurry with the first test the Soviet leadership was concerned about the possible U.S. reaction on its loosing of nuclear monopoly and ordered at that stage to slow down the work on preparation of the test itself and to speed up the accumulation of Plutonium for the second charge to have a hedge for the case of American decision to attack in response of the Soviet nuclear test. (28)
After the successful test of August 29, 1949 at the Test Range Number 2 of the Ministry of Defense in Kazakhstan (military unit 52605, also known as Semipalatinsk Test Range) five pre-production design RDS-1 bombs ("Article 501 Index "O"") were assembled during 1950 in KB-11 and stored in the laboratory's explosive tests zone as the State Emergency Reserve Stock.
The construction of the Plant No 551 to assemble annually 20 production RDS-1 bombs ("Article 501 Index "S"") in the zone adjacent to the territory occupied by the KB-11 was ordered on February 14, 1950 by the Council of Ministers' resolution and the Order No 43ss of the First Chief Directorate (PGU - the body which, under the Special Committee's supervision, administered all the work related with the atomic bomb design and production. The Second Chief Directorate administered work on supply of Uranium to the nuclear weapons program.)
Meanwhile it was only in 1953 when the 40 kt RDS-3T "Tatyana" first production free-fall atomic bomb for strategic bombers began entering service with the Soviet Army Air Force. The next year - which was the ninth year since the beginning of the Soviet military nuclear project - the RDS-4 bomb for tactical bombers entered the service. It is noteworthy that RDS-4 had the same yield-to-weight ratio as the Mk-5 first U.S. light-weight tactical gravity bomb that entered the service in 1952 - on the tenth year of the U.S. military nuclear program. (29)
As early as in Spring 1948 the Soviet Government made the decision to establish the special research group to study the basic principles of thermo-nuclear explosive device. Such the group headed by Igor Tamm was established that Summer in the Physical Institute of Academy of Sciences (FIAN) in Moscow. (30)
While the Tamm's group originally began with the same idea as Edward Teller did in Los-Alamos in 1946 (i.e. the Super spherical design with thermo-nuclear component encircling the atomic trigger) later Summer 1948 Andrey Sakharov who was the member of the group and (in that time) Tamm's post-graduate student proposed the new idea. As it becomes clear from the recently declassified files of the VNIIEF the Sakharov's idea supposed the physical separation of the trigger and the thermo-nuclear secondary as the basic principle for the RDS-6S "super-article" design. (It is noteworthy that even in the top-secret hand-written document Sakharov called the atomic bomb (trigger) an "article", hence the whole design was given by him the "super-article" title.)
By February 1950 the Sakharov's idea was accepted and its putting into the life was considered necessary. Sakharov with Igor Tamm and Yury Romanov came on March 17, 1950 to Arzamas-16 and the next day the development of the two-stage thermo-nuclear device was launched in practical terms. (31)
It seems that the word about President Truman's January 31, 1950 decision to launch officially the H-bomb development was the most important single factor which gave the push to the Soviet thermo-nuclear weapons designing. No doubts the Soviet intelligence informed the USSR top leadership not only about the decision itself but about the arguments the U.S. H-bomb supporters used to prove the idea for Truman. Those were that possession by the USA of the H-bomb offered a return to nuclear supremacy over the Soviet Union and possibility to dictate the United States' will. (32)
Later on the "yield race" of hydrogen warheads took place in major part due to the Soviet leadership's urge for proving of absence of the U.S. supremacy. (33)