First Soviet Atomic Bomb (1949): The RDS-1 Test in Kazakhstan

The first Soviet atomic bomb, known as RDS-1, was exploded on 29 August 1949 at the Semipalatinsk Test Site on the steppe of the Kazakh Soviet Socialist Republic. The test made the Soviet Union the world’s second nuclear power and ended the four-year American monopoly on atomic weapons. Its discovery shocked Washington and set off an arms race that shaped the rest of the Cold War.

Background: catching up with the Manhattan Project

Soviet physicists had studied nuclear fission since its discovery in 1938, and a small research programme began during the Second World War under the physicist Igor Kurchatov. Wartime shortages limited what it could do. Meanwhile Soviet intelligence obtained a great deal of information about the American and British effort, the Manhattan Project, from sources including the German-born British physicist Klaus Fuchs, who worked at Los Alamos.

The atomic bombing of Hiroshima in August 1945 transformed the programme. Stalin made the bomb a top state priority, and on 20 August 1945 a Special Committee was created under Lavrentiy Beria, the head of the security apparatus. Beria commanded vast resources, including prison labour from the Gulag system, to build mines, reactors and secret cities.

Building the bomb

The project faced three main tasks: finding uranium, producing fissile material and designing a weapon. Uranium came from deposits in the Soviet Union and from mines in occupied eastern Germany and Czechoslovakia. German scientists brought to the Soviet Union after the war also contributed to isotope separation and materials work.

Kurchatov’s team started the first Soviet nuclear reactor, F-1, in Moscow on 25 December 1946, the first self-sustaining chain reaction in Europe. A full-scale plutonium production reactor went into operation in June 1948 at the secret complex of Chelyabinsk-40 in the Urals, today known as Mayak. Workers there were exposed to high levels of radiation as the plant was rushed into service.

The bomb itself was designed at the secret laboratory KB-11, in the closed town later known as Arzamas-16 (Sarov), under the scientific direction of Yulii Khariton. Beria insisted that the first device should copy the proven American plutonium implosion design used at Nagasaki, to reduce the risk of failure. Soviet scientists had already worked on their own improved designs, which were tested later.

The test on 29 August 1949

The Semipalatinsk site, an area of steppe in north-eastern Kazakhstan, was chosen for its remoteness, though villages lay within range of fallout. Engineers built a tower for the device and laid out buildings, bridges, vehicles, animals and military equipment at various distances to measure the effects of the blast.

The bomb was detonated at 7 a.m. local time on 29 August 1949. Its yield was about 22 kilotons of TNT, similar to the Nagasaki bomb. Kurchatov and Beria watched from an observation post. The test was code-named First Lightning, and the device was called RDS-1, a designation of uncertain meaning that later prompted the popular backronym Rossiya delaet sama (“Russia does it herself”).

The pressure on those involved was immense. Participants later recalled that the scientific leaders understood failure might cost them their positions or worse, given Beria’s methods and Stalin’s personal interest. When the flash and the rising cloud confirmed success, the result was reported to Stalin, and leading scientists and engineers received high honours, cash bonuses, cars and dachas in a secret decree that autumn.

Myths and facts

A common belief is that the Soviet bomb was simply stolen. Espionage certainly saved time: historians generally estimate that it shortened the Soviet programme by one to two years, mainly by confirming which paths worked and by supplying the implosion design. But the Soviet Union still had to find and mine uranium, build reactors and chemical separation plants, and produce enough pure plutonium, which required tens of thousands of workers and huge industrial effort.

Another misconception is that the test was immediately public. In fact the Soviet leadership kept it secret, and the world learned of it only because American air sampling detected the fallout. Soviet citizens were told little more than the brief TASS statement for years afterwards.

Key people

• Igor Kurchatov (1903–1960), scientific director of the Soviet atomic project.
• Lavrentiy Beria (1899–1953), head of the Special Committee that ran the programme.
• Yulii Khariton (1904–1996), chief designer of the bomb at KB-11.
• Joseph Stalin, Soviet leader, who set the project’s priority and deadlines.
• Klaus Fuchs (1911–1988), physicist whose espionage gave Moscow key details of the implosion design.

Detection and announcement

The Soviet government made no announcement. In early September 1949, however, a US Air Force WB-29 weather reconnaissance flight from Japan collected radioactive debris over the North Pacific. American and British scientists analysed the samples and concluded that a plutonium bomb had been exploded in Soviet Asia. US intelligence had estimated that the Soviet Union would not have a bomb before the early to mid-1950s.

On 23 September 1949 President Harry S. Truman announced that there was evidence of a recent atomic explosion in the Soviet Union. The Soviet news agency TASS replied on 25 September, without confirming a test directly, that the Soviet Union had possessed the secret of the atomic weapon since 1947.

Consequences

The end of the American monopoly changed US policy quickly. On 31 January 1950 Truman ordered work to proceed on the hydrogen bomb. In April 1950 the policy paper NSC-68 called for a large military build-up to counter Soviet power. Klaus Fuchs confessed to British investigators and was arrested in February 1950, and the hunt for his contacts led to the arrest of Julius and Ethel Rosenberg later that year.

The Soviet Union tested its second atomic device in 1951 and its first thermonuclear-type device in August 1953. Semipalatinsk remained its main test site until 1989, hosting about 456 nuclear explosions, more than a hundred of them in the atmosphere before the Partial Nuclear Test Ban Treaty of 1963. Studies have linked the fallout to elevated rates of cancer and other illness among the region’s population, though estimates of the scale of harm vary.

Local Kazakh villagers were rarely warned or evacuated during the early atmospheric tests, and for decades official secrecy prevented open discussion of the risks. In the late 1980s a popular protest campaign, the Nevada-Semipalatinsk movement led by the poet Olzhas Suleimenov, called for an end to testing. The last Soviet test at the site took place in 1989, and two years later the newly assertive government of Kazakhstan ordered the site closed on the anniversary of the first explosion. Kazakhstan later gave up the nuclear weapons it inherited from the Soviet Union, and the United Nations chose 29 August as the International Day against Nuclear Tests.

Timeline

• 1945, 20 August: Stalin’s government creates the Special Committee on the atomic bomb under Beria.
• 1946, 25 December: The F-1 reactor in Moscow achieves a chain reaction.
• 1948, June: The plutonium production reactor at Chelyabinsk-40 begins operating.
• 1949, 29 August: RDS-1 is detonated at Semipalatinsk.
• 1949, early September: A US WB-29 flight detects radioactive debris.
• 1949, 23 September: Truman announces the Soviet explosion.
• 1950, 31 January: Truman approves the hydrogen bomb programme.
• 1991, 29 August: Kazakhstan closes the Semipalatinsk Test Site.

Why it matters

RDS-1 turned the Cold War into a confrontation between two nuclear-armed superpowers. It accelerated the arms race, deepened Western fears of espionage and left a lasting human and environmental legacy in Kazakhstan.