| The first nuclear test was conducted by
| |
| | Treaty was signed in 1963. Above are the
|
| the United States on July 16, 1945,
| |
| | per capita thyroid doses (in rads) in the
|
| during the Manhattan Project, and given
| |
| | continental United States resulting from
|
| the codename "Trinity". The test was
| |
| | all exposure routes from all atmospheric
|
| originally to confirm that the
| |
| | nuclear tests conducted at the Nevada
|
| implosion-type nuclear weapon design was
| |
| | Test Site from 1951-1962.
|
| feasible, and to give the scientists and
| |
| | Bravo was the worst U.S. nuclear
|
| military officers an idea of what the
| |
| | accident, but many of its component
|
| actual size and effects of a nuclear
| |
| | problems — unpredictably large yields,
|
| explosion would be before they were used
| |
| | changing weather patterns, unexpected
|
| in combat against Japan. While the test
| |
| | fallout contamination of populations and
|
| gave a good approximation of many of the
| |
| | the food supply — occurred during other
|
| explosion's effects, it did not give an
| |
| | atmospheric nuclear weapons tests by
|
| appreciable understanding of nuclear
| |
| | other countries as well. Concerns over
|
| fallout, which was not well understood by
| |
| | worldwide fallout rates eventually lead
|
| the project scientists until well after
| |
| | to the Partial Test Ban Treaty in 1963,
|
| the atomic bombings of Hiroshima and
| |
| | which limited signatories to only
|
| Nagasaki.
| |
| | underground testing. Not all atmospheric
|
| The United States conducted only six
| |
| | tests stopped, however, but because the
|
| nuclear tests before the Soviet Union
| |
| | United States and the Soviet Union in
|
| developed their first atomic bomb (Joe 1)
| |
| | particular stopped testing aboveground it
|
| and tested it on August 29, 1949. Neither
| |
| | cut the number of atmospheric tests down
|
| country had very many nuclear weapons to
| |
| | substantially, since around 86% of all
|
| spare at first, and so testing was
| |
| | nuclear tests were conducted by those two
|
| relatively limited (when the U.S. used
| |
| | countries. France continued atmospheric
|
| two weapons for Operation Crossroads in
| |
| | testing until 1974, and People's Republic
|
| 1946, they were detonating over 20% of
| |
| | of China until 1980.
|
| their current arsenal). However, by the
| |
| | Almost all new nuclear powers have
|
| 1950s the United States had established a
| |
| | announced their possession of nuclear
|
| dedicated test site on its own territory
| |
| | weapons with a nuclear test. The only
|
| (Nevada Test Site) and were also using a
| |
| | acknowledged nuclear power which claims
|
| site in the Marshall Islands (Pacific
| |
| | to have never conducted a test was South
|
| Proving Grounds) for extensive nuclear
| |
| | Africa (see Vela Incident), which has
|
| testing.
| |
| | since claimed to have dismantled all of
|
| The early tests were used primarily to
| |
| | its weapons. The state of Israel is
|
| discern the military effects of nuclear
| |
| | widely thought by intelligence agencies
|
| weapons (Crossroads had involved the
| |
| | to possess a sizeable nuclear arsenal,
|
| effect of nuclear weapons on a navy, and
| |
| | though it has never tested. Experts
|
| how they functioned underwater) and to
| |
| | disagree on whether states can have
|
| test new weapon designs. During the 1950s
| |
| | reliable nuclear arsenals — especially
|
| these included new hydrogen bomb designs,
| |
| | ones using advanced warhead designs, such
|
| which were tested in the Pacific, and
| |
| | as hydrogen bombs and miniaturized
|
| also new and improved fission weapon
| |
| | weapons — without testing, though all
|
| designs. The Soviet Union also began
| |
| | agree that it is very unlikely to develop
|
| testing on a limited scale, primarily in
| |
| | significant nuclear innovations without
|
| Kazakhstan. During the later phases of
| |
| | testing. One other approach is to use
|
| the Cold War, though, both countries
| |
| | supercomputers to conduct "virtual"
|
| developed accelerated testing programs,
| |
| | testing, but the value of these
|
| testing many hundreds of bombs over the
| |
| | simulations without actual test result
|
| last half of the twentieth century.
| |
| | data is thought to be slim.
|
| Nuclear tests can involve many hazards. A
| |
| | Some nuclear testing has been for
|
| number of these were best illustrated in
| |
| | "peaceful" purposes. These so-called
|
| the U.S. Castle Bravo test in 1954. The
| |
| | peaceful nuclear explosions were used to
|
| weapon design tested was a new form of
| |
| | evaluate whether nuclear explosions could
|
| hydrogen bomb, and the scientists
| |
| | be used for non-military purposes such as
|
| underestimated how vigorously some of the
| |
| | digging canals and artificial harbors, or
|
| weapon materials would react. As a
| |
| | to stimulate oil and gas fields. In most
|
| result, the explosion — with a yield of
| |
| | cases the results were too radioactive
|
| 15 Mt — was over twice what was
| |
| | for use, and the programs proved neither
|
| predicted. Aside from this problem, the
| |
| | economically sound or politically
|
| weapon also generated a large amount of
| |
| | favorable.
|
| radioactive nuclear fallout, more than
| |
| | Nuclear testing has also been used for
|
| had been anticipated, and a change in the
| |
| | clearly political purposes. The most
|
| weather pattern caused the fallout to be
| |
| | explicit example of this was the
|
| spread in a direction which had not been
| |
| | detonation of the largest nuclear bomb
|
| cleared ahead of time. The fallout plume
| |
| | ever created, the 50 megaton Tsar Bomba
|
| spread high levels of radiation for over
| |
| | (with a maximum yield of 150 Mt), by the
|
| a hundred miles, contaminating a number
| |
| | Soviet Union in 1961. This weapon was too
|
| of populated islands in nearby atoll
| |
| | large to be practically used against an
|
| formations (though they were soon
| |
| | enemy target, and it is not thought that
|
| evacuated, many of the islands'
| |
| | any were actually manufactured except the
|
| inhabitants suffered from radiation burns
| |
| | one which was detonated in the test. The
|
| and later from other effects such as
| |
| | weapon was used by the USSR as a show of
|
| increased cancer rate and birth defects),
| |
| | Soviet strength and force, rather than to
|
| as well as a Japanese fishing boat (Daigo
| |
| | be developed as an actual weapon or for
|
| Fukuryu Maru). One member of the boat's
| |
| | specifically scientific purposes.
|
| crew died from radiation sickness after
| |
| | There have been many attempts to limit
|
| returning to port, and it was feared that
| |
| | the number and size of nuclear testing;
|
| the radioactive fish they had been
| |
| | the most far-reaching was the
|
| carrying had made it into the Japanese
| |
| | Comprehensive Test Ban Treaty of 1996,
|
| food supply.
| |
| | which was not ratified by the United
|
| Because of concerns about worldwide
| |
| | States. Nuclear testing has since become
|
| fallout levels, the Partial Test Ban
| |
| | a controversial issue in the United
|
| Treaty was signed in 1963. Above are the
| |
| | States, with a number of politicians
|
| per capita thyroid doses (in rads) in the
| |
| | saying that future testing might be
|
| continental United States resulting from
| |
| | necessary to maintain the aging warheads
|
| all exposure routes from all atmospheric
| |
| | from the Cold War. Because nuclear
|
| nuclear tests conducted at the Nevada
| |
| | testing is seen as furthering nuclear
|
| Test Site from 1951-1962.
| |
| | arms development, many are also opposed
|
| Because of concerns about worldwide
| |
| | to future testing as an acceleration of
|
| fallout levels, the Partial Test Ban
| |
| | the arms race.
|
