Development of Soviet nuclear weapon - Historum

Edward · October 8th, 2012, 11:24 PM

29 August 1949 –test of the RDS-1, the first Soviet atomic bomb take place at 7 am loca time (4 am. Moscow time) at Semipalatinsk test place in today’s Kazakhstan.

RDS-1 plutonium bomb
This device was strikingly similar to “Fat Man” Nagasaki plutonium implosion bomb.

The development of this bomb is a fascinating story of great scientific effort mixed with scientific espionage which later became a trademark of KGB and GRU.

rehabnonono · October 9th, 2012, 06:12 AM

I Remember reading that the spys helped speed up the process... but that the Soviets would have eventually made one themselves.

Edward · October 9th, 2012, 07:31 PM

Basic Scientific and technical data acquired by Soviet intelligence I atomic bomb design;
1941-1942

From Great Britain -Uranium 235 is a most promising material for atomic bomb development
According to information from GB, subcritical mass of U235 was safe and stable. In mass above critical, the chain reaction will occur. idea of Gun type device was accrued with detail calculation for approach linear velocity for each half of the critical mass. (it was calculated for 6000 feet per second as a minimum for optimal explosion energy). The explosion energy was expected to be in the range 0f 1.6 kT this idea was not a novel for Russian, they proposed this solution previously by themselves but it was a good way of confirming their considerations.

1943

From GB-first data of applicability of plutonium 239 for chain reaction
According to data acquired from GB, Kurchatov noted that there will be no possibility to keep uranium 235 in supercritical mass up to the moment of explosion.
From GB-spectrum of secondary neutrons and cross section of fission of U235. It was crucial information to determine size of the bomb.
Info allowing Kurchatov to assess possibility of Plutonium production for primary atomic bomb material

1945

Data’s from US regarding design of gun-assembly principals used for uranium bomb and implosion principal proposed for Plutonium bomb. Info regarding explosion energy (higher than previously obtained from GB) as well as first data regarding thermal and radioactive effects. On this base Kurchatov decided to pursue implosion principal for their plutonium bomb.
From US-data regarding neutron reflector design made of beryllium oxide.. Crucial data for enhancing chain reaction.
Design of implosion type devices including geometry and timing of individual explosion, aluminium and uranium shell,. It was used in Soviet bomb.

There was additional data acquired by Soviet Intelligence regarding Isotope Separation and Basic Physical information (in my next post)

Edward · October 9th, 2012, 07:32 PM

Quote:

Originally Posted by rehabnonono

I Remember reading that the spys helped speed up the process... but that the Soviets would have eventually made one themselves.

Offcourse they will get it, probably 5 to 10 years later.

And many billions of rubles spent for basic development

Edward · October 9th, 2012, 11:19 PM

Basic physical data acquired by Soviet Intelligence Services.

1941-1942

From the data acquired from Great Britain, the critical mass of Uranium 235 ranged from 9 to 43 kg depending of the assumed fission cross-section. Actually, the critical mass of U235 is around 50 kg-depending of purity of the uranium isotope. Russian made an error assuming 10 kg as a critical mass and this value was presented in Beria report to Stalin. This underestimation of U235 required lead to same delay with Uranium bomb development and final decision to use plutonium for first device ( the US bomb tested in Alamogordo range as well as Nagasaki bomb were plutonium bombs, Hiroshima was an Uranium bomb)

1943

Spontaneous fission demonstration was confirmed by data acquired from GB
Correct nuclear fission cross-section for U235 was acquired fro GB. Kurchatov confirmed significance of this data for further development of the Bomb.
From GB data regarding secondary neutrons released per fission (2-3 neutrons) this data included the energy of secondary neutrons.

1944

Information received on the phenomenon of radioactive neutron capture by U235 and P239 isotopes. This information included confirmation that the slow neutrons could be used to initiate fission
Data regarding neutron-uranium –lead,-oxygen,-and –hydrogen interaction cross-sections
Data on the number of neutrons at spontaneous fission.

1945

Very accurate data for cross-section of U235 and P239 fission driven by various –energy fast neutrons was acquired including critical radi for U235 and P239
Accurate data for on number of secondary neutrons produced by fission
Data on spontaneous fission on plutonium P240
Data was received on the detonation wave propagation scheme, reflector material deformation and explosion-driven compression of objects
Data on properties of plutonium in different phases and its compressibility
Data on applicability of U235 for atomic bomb

Edward · October 10th, 2012, 11:18 PM

Isotope Separation data acquired by Soviet intelligence

1941-1942

According to document obtained from great Britain, the material for atomic bomb (Uranium U235) ,it was recommended that diffusion technicue was used for isotope separation. Uranium hehafluoride was intended to be used for separation

1943

From GB, the documents on gas diffusion were obtained. The only reasonable way to separate uranium isotope. The document included enough information to build separation facility in Soviet Union. Up to date, Soviet scientists considered diffusion method as impractical and the development went towards centrifugal gaseous separation, which was a less efficient methods (however it was practical)
From GB another document was received discussing all aspects of thermal diffusion, centrifugation and electromagnetic uranium isotope separation which helped to choose the right method without all necessary test and computations.
From USA documents was received confirming that gaseous diffusion was a most suitable method for isotope separation. Confirmation that USA already started construction of such facilities.

1944

Data was received on using fluorocarbons as lubricants in the separation facility and on method of their chemical synthesis
Data of uranium metal reduction from uranium tetra-fluoride

More info about information stolen from GB and USA by Soviet Intelligence (on reactor design) will be included in my next post. My source material is printed so I have to type the most relevant sections.

asnys · October 11th, 2012, 03:48 AM

Quote:

Originally Posted by Edward

From GB, the documents on gas diffusion were obtained. The only reasonable way to separate uranium isotope. The document included enough information to build separation facility in Soviet Union. Up to date, Soviet scientists considered diffusion method as impractical and the development went towards centrifugal gaseous separation, which was a less efficient methods (however it was practical)

Actually, centrifugal separation is more efficient than gaseous diffusion. The US and UK just thought it was impractical after our initial experiments in it failed pretty badly, due to some poor design choices. In the early 50s, the Soviets - with the aid of about 60 German and Austrian engineers, notably Gernot Zippe - developed the Zippe centrifuge, which, updated with modern materials, is the most efficient separation method used in the world today. (Although GE's SILEX process might be about to displace it.) The US and Europe didn't realize the significance of the method until the late 50s/early 60s, when Gernot Zippe was released to return to the West. A good source on this is The End of Manhattan: How the Gas Centrifuge Changed the Quest for Nuclear Weapons, by R. Scott Kemp (first page only).

**Belgarion** · October 11th, 2012, 05:00 AM

Quote:

Originally Posted by rehabnonono

I Remember reading that the spys helped speed up the process... but that the Soviets would have eventually made one themselves.

Julius and Ethel Rosenberg and their assosciates. The Rosenbergs were executed for espionage in 1953.

Edward · October 16th, 2012, 10:38 PM

Quote:

Originally Posted by asnys

Actually, centrifugal separation is more efficient than gaseous diffusion. The US and UK just thought it was impractical after our initial experiments in it failed pretty badly, due to some poor design choices. In the early 50s, the Soviets - with the aid of about 60 German and Austrian engineers, notably Gernot Zippe - developed the Zippe centrifuge, which, updated with modern materials, is the most efficient separation method used in the world today. (Although GE's SILEX process might be about to displace it.) The US and Europe didn't realize the significance of the method until the late 50s/early 60s, when Gernot Zippe was released to return to the West. A good source on this is The End of Manhattan: How the Gas Centrifuge Changed the Quest for Nuclear Weapons, by R. Scott Kemp (first page only).

My information regarding separation methods is from Russian sources. In any case they have been convinced at that time that diffusion is the most economical way of separation. As almost all early Atomic bombs in Russia were Plutonium bomb, I think that the separation of uranium isotopes was of importance to Soviet only in the very beginning.

Edward · October 16th, 2012, 11:06 PM

Information obtained by Soviet Intelligence regarding Nuclear Reactors design

1942-1943

From GB data were obtained regarding chain reaction feasibility in natural uranium oxide (or Uranium metal) mixed with heavy water.

Kurchatov as well as other soviet scientists were surprised with these data. It saved Soviets years of experimentations. Also Soviet did not posses any amount of Heavy water to start such investigation. This info was of enormous significance for Soviets.

Confirmation com from GB that there is a possibility to produce Plutonium 239 (element-94) from uranium pile by capturing neutrons by inert uranium U238 . This method was used to produce Bomb Grade Plutonium for Soviet Bombs.It also saved a lot of effort to separate isotopes of Uranium for this purpose.
From US data of Heavy Water production facility for monthly output of 250 kg.

1944

From US the data regarding reactor based on ordinary water and metallic uranium.
From US data were received on methods for uranium purification from neutron-absorbing impurities.
Cooling method for Uranium-Graphite pile by water and helium. (from US)
From US-data on uranium lattice in graphite, thermal neutron distribution and in pile process control using boron or cadmium neutron absorbing rods
Data regarding heavy water requirement for heavy water pile (3 to 4 tons)
Data obtained on the piles based on ordinary water and rods of Uranium enriched in Uranium 235