Soviet atomic bomb project

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Soviet atomic bomb project
From top to bottom, left to right: Abram Ioffe, Abram Alikhanov, and Igor Kurchatov Model of the F-1 reactor RBMK reactor similar to Mayak plutonium production reactors Diagram of an implosion bomb passed by atomic spy David Greenglass Replica of RDS-1 US estimations of RDS-1 location, 1949 Test crater at the Semipalatinsk Test Site
Operational scope	Operational R&D
Location	Kurchatov Institute, Moscow Design Bureau 11, Arzamas-16 Semipalatinsk Test Site, Kazakhstan
Planned by	NKVD, NKGB, MGB PGU GRU
Date	1942–1949
Executed by	Soviet Union
Outcome	Successful development of a plutonium implosion weapon United States accelerates development of the hydrogen bomb

The Soviet atomic bomb project was authorized by Joseph Stalin in the Soviet Union to develop nuclear weapons during and after World War II.^[1][2]

Russian physicist Georgy Flyorov suspected that the Allied powers were secretly developing a "superweapon"^[2] since 1939. Flyorov urged Stalin to start a nuclear program in 1942.^{[3]: 78–79} Early efforts mostly consisted of research at Laboratory No. 2 in Moscow, and intelligence gathering of Soviet-sympathizing atomic spies in the US Manhattan Project.^[1] Subsequent efforts involved plutonium production at Mayak in Chelyabinsk and weapon research and assembly at KB-11 in Sarov.

After Stalin learned of the atomic bombings of Hiroshima and Nagasaki, the nuclear program was accelerated through intelligence gathering about the Manhattan Project and German nuclear weapon project.^[4] Espionage coups, especially via Klaus Fuchs and David Greenglass, included detailed descriptions of the implosion-type Fat Man bomb and plutonium production. In the final months of the war, the Soviet "Russian Alsos" task force competed against the Western Allies' Alsos Mission to capture German and Austrian nuclear scientists and material, including refined uranium and cyclotrons.^{[5]: 242–243} The Soviet project utilized East German industry for further uranium mining, refinement, and instrument manufacture. Lavrentiy Beria was placed in charge of the atomic project, and the replication of the Nagasaki plutonium weapon was prioritized.^[6]

The Manhattan Project had established a monopoly on the global uranium market. The Soviet project relied on SAG Wismut in East Germany and the development of the Taboshar mine in Tajikistan. Domestic large-scale production of high purity graphite and high purity uranium metal, to construct plutonium production reactors, was a significant challenge.

In late 1946, F-1, the first nuclear reactor outside North America, achieved criticality at Laboratory No. 2, led by Igor Kurchatov. In mid-1948, the A-1 plutonium production reactor became operational at the Mayak Production Association, and in mid-1949, the first plutonium metal was separated.^[7] The first nuclear weapon was assembled at the KB-11 design bureau, led by Yulii Khariton, in the closed city of Arzamas-16 (Sarov).^[8]

On 29 August 1949, the Soviet Union secretly and successfully conducted its first weapon test, RDS-1, at the Semipalatinsk Test Site of the Kazakh SSR.^[1] Simultaneously, project scientists had been developing conceptual thermonuclear weapons. The US detection of test, via anticipatory atmospheric fallout monitoring, led to a more rapid US program to develop thermonuclear weapons, and marked the opening of the nuclear arms race of the Cold War.

Following RDS-1, the Soviet nuclear program rapidly expanded. Boosted fission and multi-stage thermonuclear weapons were developed during the 1950s, testing expanded to Novaya Zemlya and Kapustin Yar, and fissile material production sites grew, including the invention of the gas centrifuge. The program created demand for nuclear weapons delivery, influencing the Soviet space program.