RDS-37 was the Soviet Union's

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 first "true" (staged) hydrogen bomb, first tested on November 22, 1955. The weapon had a nominal yield

Nuclear weapon yield

The explosive yield of a nuclear weapon is the amount of energy discharged when a nuclear weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene , either in kilotons or megatons , but sometimes also in terajoules...

 of approximately 3 megatons

TNT equivalent

TNT equivalent is a method of quantifying the energy released in explosions. The ton of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT...

. It was scaled down to 1.6 megatons for the live test.

It was a multi-stage thermonuclear device which utilized radiation implosion

Radiation implosion

The term radiation implosion describes the process behind a class of devices which use high levels of electromagnetic radiation to compress a target...

 called Sakharov

Andrei Sakharov

Andrei Dmitrievich Sakharov was a Soviet nuclear physicist, dissident and human rights activist. He earned renown as the designer of the Soviet Union's Third Idea, a codename for Soviet development of thermonuclear weapons. Sakharov was an advocate of civil liberties and civil reforms in the...

s "Third Idea" in the USSR (the Teller–Ulam design in the USA). It utilized a dry lithium deuteride fusion fuel, with some of it replaced with a "passive material" to reduce its total yield. Despite this reduction in yield, because the weapon exploded under an inversion layer

Inversion (meteorology)

In meteorology, an inversion is a deviation from the normal change of an atmospheric property with altitude. It almost always refers to a temperature inversion, i.e...

 much of its shock wave was focused backward at the ground unexpectedly, causing a site building to collapse and kill three people.

It was air-dropped at Semipalatinsk Test Site, Kazakhstan, making it the first air-dropped two-stage thermonuclear test. The RDS-6s

Joe 4

Joe 4 was an American nickname for the first Soviet test of a thermonuclear weapon on August 12, 1953. It utilized a scheme in which fission and fusion fuel were "layered", a design known as the Sloika model in the Soviet Union...

 device (Joe-4) exploded in 1953 was labeled as a "hydrogen bomb" as well but was more similar to a "boosted

Boosted fission weapon

A boosted fission weapon usually refers to a type of nuclear bomb that uses a small amount of fusion fuel to increase the rate, and thus yield, of a fission reaction. The neutrons released by the fusion reactions add to the neutrons released in the fission, as well as inducing the fission reactions...

" fission bomb than a megaton range hydrogen bomb.

See also

• RDS-1
  Joe 1
  The RDS-1 , also known as First Lightning , was the Soviet Union's first nuclear weapon test. In the west, it was code-named Joe-1, in reference to Joseph Stalin. It was test-exploded on 29 August 1949, at Semipalatinsk, Kazakh SSR, after a top-secret R&D project...
  
  
• Soviet atomic bomb project
  Soviet atomic bomb project
  The Soviet project to develop an atomic bomb , was a clandestine research and development program began during and post-World War II, in the wake of the Soviet Union's discovery of the United States' nuclear project...
  
  
• Ivy Mike
  Ivy Mike
  Ivy Mike was the codename given to the first United States test of a thermonuclear weapon, in which a major part of the explosive yield came from nuclear fusion. It was detonated on November 1, 1952 by the United States at on Enewetak, an atoll in the Pacific Ocean, as part of Operation Ivy...
  
   (first US hydrogen bomb)
• Castle Bravo
  Castle Bravo
  Castle Bravo was the code name given to the first U.S. test of a dry fuel thermonuclear hydrogen bomb device, detonated on March 1, 1954 at Bikini Atoll, Marshall Islands, as the first test of Operation Castle. Castle Bravo was the most powerful nuclear device ever detonated by the United States ,...
  
  (first US staged dry-fuel design)

External links

• Soviet and Nuclear Weapons History
• Video of the RDS-37 Nuclear Test