RDS-6s (the "Sakharov Layer Cake") was the first Soviet thermonuclear device, successfully tested on August 12, 1953, at the Semipalatinsk Test Site. The yield was 400 kilotons of TNT equivalent, three thousand times the power of the atomic bomb dropped on Hiroshima.[2] The chief designer and direct head of the development effort was Yuliy Borisovich Khariton, a Nizhny Novgorod native; the work was carried out at KB-11 — now the Russian Federal Nuclear Center, the All-Russian Scientific Research Institute of Experimental Physics (RFNC-VNIIEF) in Sarov.[3]
History of Development
Work on the future device began in June 1946 in Moscow, at the Institute of Chemical Physics, under the leadership of Yakov Borisovich Zeldovich. Two fundamentally different physical designs were explored in parallel: Andrey Dmitrievich Sakharov's "layer cake" (RDS-6s) and Zeldovich's "pipe" (RDS-6t). In the course of the work, the "pipe" design was rejected.[2]
In 1948, the group of Igor Yevgenyevich Tamm, which included Andrey Sakharov, joined in solving the problem. In the fall of that year, Sakharov, independently of the American physicist Edward Teller, arrived at the idea of a heterogeneous design with alternating layers of deuterium and uranium-238. The underlying principle of ionization compression of the thermonuclear fuel became known as "sakharization."[3]
On May 8, 1949, Yuliy Khariton, on the instructions of Boris Vannikov, head of the First Main Directorate under the USSR Council of Ministers, prepared an assessment of Tamm's proposal, noting that Sakharov's basic idea was "extremely ingenious and physically self-evident," and he supported work on the "layer cake." Overall direction of the development was exercised by Igor Kurchatov.[3] By April 1953, all elements of the thermonuclear device had been perfected; in parallel, work proceeded on the ballistic casing and on preparing technical specifications for equipping the bomb bay of the Tu-16 long-range jet bomber.[2]
The Test
Before the test at the Semipalatinsk Test Site, 2,250 people were evacuated from the zone of possible radioactive contamination, and more than 44,000 head of livestock were removed. Igor Kurchatov directed the tests. The detonation signal was given at 7:30 a.m. on August 12, 1953.[3] It was the fourth Soviet nuclear weapons test overall.[2]
The successful test fully confirmed the physical and design principles of the device, and the TNT equivalent, within the accuracy of the measurements, matched the calculated yield of 400 kt.[3] By that time the United States had already carried out a thermonuclear explosion — on November 1, 1952, at Enewetak Atoll in the Pacific Ocean — but the American device used liquid deuterium. The Soviet "layer cake" became the first transportable thermonuclear device suitable for combat use.[2]
The work of the bomb's creators was highly praised by the Soviet government: 753 people received various awards, and ten were awarded the title of Hero of Socialist Labor.[3]
The Role of Sarov and the Nizhny Novgorod Connection
KB-11, where the main work on the RDS-6s was carried out, was located in Sarov (then a classified "Object"). Until the mid-1950s, the institution's employees and their families could not leave the zone even for vacation. The laboratories were housed in former monastery buildings of the Sarov Hermitage.[2] Yuliy Borisovich Khariton, a native of Saint Petersburg, headed KB-11 and became chief designer of the RDS-6s; his 1949 conclusion on the promise of the "Sloika" (layer cake) was the key administrative decision that opened the way for the project.[3]
In 2013, Sarov hosted the first conference of young scientists, "The Nuclear Shield and Sword of Russia," dedicated to the 60th anniversary of the RDS-6s test. About three hundred specialists from the nuclear weapons complex of Rosatom, the Ministry of Defense, and VNIIEF took part.[1] In 2023, RFNC-VNIIEF marked the 70th anniversary of the "Sakharov Sloika" with a ceremonial session of the Scientific and Technical Council; Academician Radiy Ilkaev, the center's honorary scientific director, called the RDS-6s test the moment when "the Soviet Union truly became a nuclear power."[3]
Significance
The RDS-6s test laid the foundations of nuclear deterrence and shaped the Soviet thermonuclear arsenal for decades to come. The design ideas of the "Sloika" had a lasting influence on the further development of thermonuclear weapons in the USSR.[3] Thanks to the work on the device, the country created new branches of industry and new fields of fundamental science in a short time.[3]
Sources
- NNTV — The first conference of young scientists, "The Nuclear Shield and Sword of Russia," dedicated to the sixtieth anniversary of the test of the first thermonuclear bomb RDS-6S, is taking place in Sarov
- Nizhegorodskiye Novosti — Americans Choked on the "Sloika"
- topwar.ru — The Superbomb