The United States performed nuclear weapons tests from 1945 to 1992 as part of the nuclear arms race. By official count, there were 1,054 nuclear tests conducted, including 215 atmospheric and underwater tests.Discrepancies between the below table and the official report include 28 tests actually carried out by the United Kingdom at the NTS; four aborted tests in Operation Fishbowl; one test, Anvil/Peninsula, that jammed during lowering in its shaft and was abandoned; and five salvo tests listed as two enumerated tests each because they were treated that way when eventually described to the public, rather than standing on the treaty definition of a salvo test.
Most of the tests took place at the Nevada Test Site (NNSS/NTS), the Pacific Proving Grounds in the Marshall Islands or off Kiritimati Island in the Pacific, plus three in the Atlantic Ocean. Ten other tests took place at various locations in the United States, including Alaska, Nevada (outside of the NNSS/NTS), Colorado, Mississippi, and New Mexico.
United States nuclear tests
+ Summary of US nuclear testing series Series or years Years covered TestsIncludes all tests with potential for nuclear fission or fusion explosion, including combat use, singleton tests, salvo tests, zero yield fails, safety experiments, and bombs incapacitated by accidents but still intended to be fired. It does not include hydronuclear and subcritical tests, and misfires of a device which was subsequently fired successfully. Devices fired Devices with unknown yield Peaceful use tests Non-PTBT testsNumber of tests which would have been in violation of the Partial Test Ban Treaty of 1963, such as atmospheric, space or underwater tests. Some "peaceful use" cratering tests which should have been violations were protested, and later quietly dropped. Yield range (kilotons)"Small" refers to a value greater than zero but less than 0.5 kt. Total yield (kilotons)Some yields are described like "< 20 kt"; such are scored at one half of the numeric amount, i.e., yield of 10k in this example. "Unknown yield" adds nothing to the total. Notes Trinity 1945
21
First nuclear weapons test, conducted as part of the Manhattan Project. Tested the Mark 3 Fat Man design. Crossroads 1946
21
First postwar test series Sandstone 1948
18 to 49
The first use of "levitated" cores made of oralloy. Tested components for Mark 4 design. Ranger 1951
1 to 22
First tests at the Nevada Test Site. Operation originally named "Operation Faust". Greenhouse 1951
46 to 225
George shot was the first thermonuclear device, an unweaponized physics experiment; Item shot was first boosted fission weapon. Buster-Jangle 1951
small to 31
The first series in which troop maneuvers (Desert Rock exercises) were performed Tumbler-Snapper 1952
1 to 31
First boosted fission weapon tests in the continental United States Ivy 1952
500 to 10,400
Mike shot was the first multi-megaton thermonuclear weapon, first death related to nuclear testing, of sampler pilot. King shot remains largest fission weapon to not attempt boosting. Upshot-Knothole 1953
small to 61
First thermonuclear weapon tests in the continental US. 18,000 men exposed in Desert Rock V up to 26.6 REM. 84 exceeded current yearly limits of 5 REM/yr. Castle 1954
110 to 15,000
Bravo shot inspired secret Project 4.1 to study fallout victims. It over-produced by 250% of expected yield, causing fallout over a wide area. Teapot 1955
1 to 43
Wigwam 1955
30
underwater Project 56 1955–1956
0 to 0
Redwing 1956
small to 5,000
Cherokee was first US airdrop of thermonuclear weapon, Zuni was first US test of three-stage thermonuclear weapon. First use of the "materials substitution method", a lead tamper instead of a natural uranium one. First series to set with "yield budget" of 20 Mt, and fission yield (effectively fallout) budget, ultimately releasing 10 Mt. Competition between UCRL and LASL over budget allocation was high. Project 57 1957
0
The first safety test, asking whether an improperly ignited bomb (as in a plane crash) would cause a nuclear blast. Plumbbob 1957
0 to 74
Included the largest atmospheric test in continental US, shot Hood Project 58+58A 1957
small to 1
Four more safety tests Hardtack I 1958
0 to 9,300
A series in the Pacific Proving Ground, including three rocket boosted high altitude tests called Operation Newsreel Argus 1958
2
Also known as Operation Floral before becoming Argus for security reasons. Tested three weapons in the South Atlantic, trying to create an artificial energy belt in the magnetosphere. Hardtack II 1958
0 to 22
Meant to squeeze all possible testing into the time before Eisenhower's test ban started on 30 October 1958. Planned as "Operation Millrace", changed to HT II when a science panel recommended to "stop testing after the Hardtack series." Nougat 1961–1962
small to 67
First all-underground test series. Included first Operation Plowshare shot "Gnome" in Carlsbad, New Mexico, which was detonated in an underground salt dome. Sunbeam 1962
small to 2
Aka Operation Dominic II. Test of small tactical warheads, including the man-portable "Davy Crockett". Last atmospheric test series over CONUS. The Army's part of Sunbeam was Operation Ivy Flats. Dominic 1962–1963
2 to 9,960
Frigate Bird was the only test of a live warhead on a strategic missile system, the UGM-27 Polaris. Series also included three high-altitude tests known as Operation Fishbowl, separated out in this text. Fishbowl 1962
400 to 1,400
The high altitude rocket part of Operation Dominic. Included several failed tests as the rockets failed for various reasons. Starfish Prime was the largest ever test in outer space. Storax 1962–1963
1 to 115
Roller Coaster 1963
0
Storage-transportation safety experiments; measured plutonium dispersal risk. Niblick 1963–1964
small to 249
Whetstone 1964–1965
small to 51
Flintlock 1965–1966
small to 365
Latchkey 1966–1967
small to 870
Crosstie 1967–1968
small to 1,300
Bowline 1968–1969
small to 1,150
Mandrel 1969–70
small to 1,900
Mandrel was largest underground test at Nevada Test Site. Emery 1970–1971
small to 220
Grommet 1971–1972
small to 4,800
Included Cannikin, the largest underground explosion ever at 5 Mt, fired under the Aleutian island Amchitka. Toggle 1972–1973
small to 250
Arbor 1973–1974
small to 150
Bedrock 1974–1975
small to 750
Anvil 1975–1976
0 to 1,000
Fulcrum 1976–1977
small to 140
Cresset 1977–1978
0 to 150
Quicksilver 1978–1979
1 to 140
Tinderbox 1979–1980
1 to 140
Guardian 1980–1981
1 to 140
Praetorian 1981–1982
1 to 140
Phalanx 1982–1983
1 to 143
Fusileer 1983–1984
small to 150
Grenadier 1984–1985
3 to 150
Charioteer 1985–1986
small to 140
Musketeer 1986–1987
3 to 150
Touchstone 1987–1988
2 to 150
Cornerstone 1988–1989
1 to 150
Aqueduct 1989–1990
small to 150
Sculpin 1990–1991
2 to 140
Julin 1991–1992
small to 100
The last test series, cut off by the negotiation of the Comprehensive Test Ban Treaty Totals 1945-Jul-16 to 1992-Sep-23 1032 1132 12 27 231 0 to 15,000 196,552 Total country yield is 36.3% of all nuclear testing.
Timeline Graphical timeline of United States atmospheric nuclear weapons tests
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