On 29 August 1949, the Soviet Union secretly conducted its first successful weapon test (First Lightning, based on the American "Fat Man" design) at the Semipalatinsk-21 in Kazakhstan. Stalin alongside Soviet political officials and scientists were elated at the successful test.

Underwater Wahoo atomic bomb explosion of 1958

Information Country United States Test series Operation Castle Test site Bikini Atoll Date May 5, 1954 Test type Atmospheric Yield 13.5 Mt

RDS-37 Soviet hydrogen bomb test (1955)

Time-lapse map of the 2053 nuclear explosions which have taken place between 1945 and 1998, beginning with the Manhattan Project's "Trinity" test near Los Alamos and concluding with Pakistan’s nuclear test Since then there has been 3 by North Korea A nuclear explosion is an explosion that occurs as a result of the rapid release of energy from a high-speed nuclear reaction. The driving reaction may be nuclear fission or nuclear fusion or a multi-stage cascading combination of the two, though to date all fusion-based weapons have used a fission device to initiate fusion, and a pure fusion weapon remains a hypothetical device. Nuclear explosions are used in nuclear weapons and nuclear testing. Nuclear weapons tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing nuclear weapons offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength. Many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status through a nuclear test

Castle Bravo was the first in a series of high-yield thermonuclear weapon design tests conducted by the United States at Bikini Atoll, Marshall Islands, as part of Operation Castle. Detonated on March 1, 1954, the device was the most powerful nuclear device detonated by the United States and its first lithium deuteride fueled thermonuclear weapon. Castle Bravo's yield was 15 megatons of TNT, 2.5 times the predicted 6.0 megatons, due to unforeseen additional reactions involving lithium-7,which led to the unexpected radioactive contamination of areas to the east of Bikini Atoll. At the time, it was the most powerful artificial explosion in history. Nuclear weapon tests are experiments carried out to determine the performance, yield, and effects of nuclear weapons. Testing a nuclear weapon offers practical information about how the weapons function, how detonations are affected by different conditions, and how personnel, structures, and equipment are affected when subjected to nuclear explosions. However, nuclear testing has often been used as an indicator of scientific and military strength. Many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status through a nuclear test A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions (thermonuclear bomb), producing a nuclear explosion. Both bomb types release large quantities of energy from relatively small amounts of matter.

The test (code name: Wahoo), took place on May 16, 1958. The detonation point was the open ocean near Enewetak Atoll in the Marshall Islands. According to the Nuclear Weapons Archive, the Wahoo device was detonated at a depth of 500 feet in 3,200 feet of water.

Atom bomb "Fat Man" destroys Nagasaki as viewed from a B-29 Superfortress accompanying the Bockscar flown by Major Charles W

Los Alamos and Dept of Defense nuclear weapons explosion shallow depth underwater shot (150 ft.), June 8, 1958, at Enewetak with a yield of 8 kilotons