Editing Soviet atomic bomb project (section)

== Espionage ==

===Soviet atomic ring===
{{Main|Nuclear espionage|Atomic spies}}
[[File:Cross-section Sketch of Atomic Bomb - NARA - 278753.jpg|thumb|right|250px|{{small|The 1945 sketch of circular shaped implosion-type passed by the American spies for the Soviet Union. This schematic was part of the development of [[RDS-1]], test fired in [[Kazakh Soviet Socialist Republic|Kazakhstan]] in [[:Category:1949 in the Kazakh Soviet Socialist Republic|1949]].}}]]The [[Nuclear espionage|nuclear]] and [[Industrial espionage|industrial]] [[espionage]]s in the [[United States]] by American sympathisers of communism who were controlled by their ''[[rezident]]'' Russian officials in [[North America]] greatly aided the speed of the Soviet nuclear program from [[History of the United States (1945–64)|1942–54]].<ref name="Harvard University press">{{cite journal|last1=Schwartz|first1=Michael I.|title=The Russian–A(merican) Bomb: The Role of Espionage in the Soviet Atomic Bomb Project|journal=J. Undgrad.Sci|date=1996|volume=3|page=108|url=http://www.hcs.harvard.edu/~jus/0302/schwartz.pdf|access-date=20 June 2017|publisher=Harvard University press|location=Harvard University|language=en|quote={{small|''There was no "Russian" atomic bomb. There only was an American one, masterfully discovered by Soviet spies."''}}|archive-date=29 October 2019|archive-url=https://web.archive.org/web/20191029164858/http://www.hcs.harvard.edu/~jus/0302/schwartz.pdf|url-status=dead}}</ref>{{rp|105–106}}<ref name="Yale University Press, Haynes">{{cite book|last1=Haynes|first1=John Earl|title=Venona: Decoding Soviet Espionage in America|date=2000|publisher=Yale University Press|location=|isbn=978-0300129878|page=400|chapter-url=https://books.google.com/books?id=M8p00bTFvRkC&q=Soviet+nuclear+espionage|access-date=20 June 2017|ref=Yale University Press, Haynes|language=en|chapter-format=googlebooks|chapter=Industrial and Atomic Espionage}}</ref>{{rp|287–305}} The willingness in sharing classified information to the Soviet Union by recruited American communist sympathizers increased when the [[USSR|Soviet Union]] faced possible defeat during the [[German invasion of Russia|German invasion]] in [[World War II]].<ref name="Yale University Press, Haynes"/>{{rp|287–289}} The Russian intelligence network in the [[United Kingdom]] also played a vital role in setting up the spy rings in the United States when the [[State Defense Committee]] approved resolution 2352<ref name=":1">{{Cite web |last=Moscow |first=Kremlin |date=28 September 1942 |title=Decree No. 2352 cc of Ukrainian State Committee of Defence |url=https://digitalarchive.wilsoncenter.org/document/decree-no-2352-cc-ukrainian-state-committee-defence |access-date=9 May 2024 |website=wilsoncenter.org}}</ref> in September 1942.<ref name="Harvard University press"/>{{rp|105–106}} This resolution instructed the Academy of Sciences of [[Ukrainian Soviet Socialist Republic|Ukrainian SSR]] to renew research efforts on nuclear energy and uranium nuclear fission and also directed the academy to report on the possibilities of a bomb or fuel source by April 1 of the following year.<ref name=":1" />

For this purpose, the spy [[Harry Gold]], controlled by [[Semyon Semyonov]], was used for a wide range of espionage that included industrial espionage in the American [[chemical industry]] and obtaining sensitive atomic information that was handed over to him by the British physicist [[Klaus Fuchs]].<ref name="Yale University Press, Haynes"/>{{rp|289–290}} Knowledge and further technical information that were passed by the American [[Theodore Hall]], a theoretical physicist, and Klaus Fuchs had a significant impact on the direction of Russian development of nuclear weapons.<ref name="Harvard University press"/>{{rp|105}}

[[Leonid Kvasnikov]], a Russian engineer turned [[KGB]] officer, was assigned for this special purpose and moved to [[New York City]] to coordinate such activities.<ref name="Regnery Publishing, Romerstein">{{cite book|last1=Romerstein|first1=Herbert|last2=Breindel|first2=Eric|title=The Venona secrets exposing Soviet espionage and America's traitors|date=2000|publisher=Regnery Pub.|location=Washington, DC|isbn=978-1596987326|url=https://books.google.com/books?id=TrlRaHFHspsC&q=soviet+espionage|access-date=21 June 2017|language=en}}</ref> [[Anatoli Yatskov|Anatoli Yatzkov]], another NKVD official in New York, was also involved in obtaining sensitive information gathered by [[Sergey Nikolaevich Kurnakov|Sergei Kournakov]] from [[Saville Sax]].<ref name="Regnery Publishing, Romerstein"/>

The existence of Russian spies was exposed by the [[United States Army|U.S. Army]]'s secretive [[Venona project]] in 1943.<ref name="Yale University Press, Powers">{{cite book|last1=Powers|first1=Daniel Patrick Moynihan|editor1-last=Gid|editor1-first=Richard|title=Secrecy : the American experience.|date=1999|publisher=Yale University Press|location=New Haven|isbn=978-0300080797|edition=New preface|url-access=registration|url=https://archive.org/details/secrecyamericane00moyn}}</ref>{{rp|54}}

In 1943, Molotov shared with Kurchatov the intelligence data accumulated through NKVD espionage. Kurchatov told Molotov, "The materials are magnificent. They add exactly what we have been missing." According to [[Richard Rhodes]], "...Kurchatov learned enough, to transform the Soviet program...information that would accelerate the Soviet program by a full two years." This included an alternative to the problem of uranium isotope separation in making a bomb. Instead, [[Plutonium-239]] could be used, which could be produced in a uranium-graphite pile through the absorption of neutrons by [[Uranium-238]]. Additionally, according to Kurchatov, the espionage material "made us include [[gaseous diffusion|diffusion]] experiments in our plans along with centrifuge."<ref name="rr">{{cite book |last1=Rhodes |first1=Richard |title=Dark Sun |date=2005 |publisher=Simon & Schuster Paperbacks |location=New York |isbn=9780684824147 |pages=71–82}}</ref>

===Soviet intelligence management in the Manhattan Project===
{{Main|History of Soviet and Russian espionage in the United States|History of Soviet espionage}}
In 1945, the Soviet intelligence obtained rough blueprints of the first U.S. atomic device.<ref>{{Cite web| title=The Russian-A(merican) Bomb: The Role of Espionage in the Soviet Atomic Bomb Project| url=http://www.hcs.harvard.edu/~jus/0302/schwartz.pdf|archiveurl=https://web.archive.org/web/20191029164858/http://www.hcs.harvard.edu/~jus/0302/schwartz.pdf|url-status=dead|archivedate=October 29, 2019|website=www.hcs.harvard.edu}}</ref><ref>The Rise and Fall of the Soviet Union
 by Martin Mccauley</ref>{{full citation needed|date=February 2025}} Alexei Kojevnikov has estimated that the primary way in which the espionage may have sped up the Soviet project was that it allowed Khariton to avoid dangerous tests to determine the size of the critical mass.{{Sfn|Kojevnikov|2004}} These tests in the U.S., known as "tickling the dragon's tail", consumed a good deal of time and claimed at least two lives; see [[Harry Daghlian]] and [[Louis Slotin]].

The published [[Smyth Report]] of 1945 on the Manhattan Project was translated into Russian, and the translators noted that a sentence on the effect of "poisoning" of Plutonium-239 in the first (lithograph) edition had been deleted from the next (Princeton) edition by [[Leslie Groves|Groves]]. This change was noted by the Russian translators, and alerted the Soviet Union to the problem (which had meant that reactor-bred plutonium could not be used in a simple gun-type bomb like the proposed [[Thin Man (nuclear bomb)|Thin Man]]).

One of the key pieces of information, which Soviet intelligence obtained from Fuchs, was a cross-section for [[Nuclear fusion|D-T fusion]]. This data was available to top Soviet officials roughly three years before it was openly published in the ''Physical Review'' in 1949. However, this data was not forwarded to [[Vitaly Ginzburg]] or [[Andrei Sakharov]] until very late, practically months before publication.{{Citation needed|date=March 2013}} Initially both Ginzburg and Sakharov estimated such a cross-section to be similar to the D-D reaction. Once the actual cross-section become known to Ginzburg and Sakharov, the Sloika design become a priority, which resulted in a successful test in 1953.

Comparing the timelines of H-bomb development, some researchers{{Who|date=August 2023}} came to the conclusion that the Soviets had a gap in access to classified information regarding the H-bomb at least between late 1950 and some time in 1953. Earlier, e.g., in 1948, Fuchs gave the Soviets a detailed update of the classical super<ref>{{cite web |title=The Classical Super is Born |url=https://www.atomicarchive.com/history/hydrogen-bomb/page-3.html |website=atomicarchive.com: Exploring the History, Science, and Consequences of the Atomic Bomb |publisher=AJ Software & Multimedia. |access-date=21 July 2023}}</ref> progress, including an idea to use lithium, but did not explain it was specifically lithium-6. By 1951 Teller accepted the fact that the "classical super" scheme wasn't feasible, following results obtained by various researchers (including [[Stanislaw Ulam]]) and calculations performed by [[John von Neumann]] in late 1950.

Yet the research for the Soviet analogue of "classical super" continued until December 1953, when the researchers were reallocated to a new project working on what later became a true H-bomb design, based on radiation implosion. This remains an open topic for research, whether the Soviet intelligence was able to obtain any specific data on Teller–Ulam design in 1953 or early 1954. Yet, Soviet officials directed the scientists to work on a new scheme, and the entire process took less than two years, commencing around January 1954 and producing a successful test in November 1955. It also took just several months before the idea of radiation implosion was conceived, and there is no documented evidence claiming priority. It is also possible that Soviets were able to obtain a document lost by [[John Archibald Wheeler|John Wheeler]] on a train in 1953, which reportedly contained key information about thermonuclear weapon design.