Storax Sedan was a shallow underground

nuclear test Nuclear weapons tests are experiments carried out to determine the performance of nuclear weapons and the effects of their explosion. Nuclear testing is a sensitive political issue. Governments have often performed tests to signal strength. Bec ...

conducted in Area 10 of

Yucca Flat Yucca Flat is a closed desert drainage basin, one of four major nuclear test regions within the Nevada Test Site (NTS), and is divided into nine test sections: Areas 1 through 4 and 6 through 10. Yucca Flat is located at the eastern edge of NTS ...

at the

Nevada National Security Site The Nevada National Security Sites (N2S2 or NNSS), popularized as the Nevada Test Site (NTS) until 2010, is a reservation of the United States Department of Energy located in the southeastern portion of Nye County, Nevada, about northwest of ...

on July 6, 1962, as part of

Operation Plowshare Project Plowshare was the overall United States program for the development of techniques to use nuclear explosives for peaceful construction purposes. The program was organized in June 1957 as part of the worldwide Atoms for Peace efforts. A ...

, a program to investigate the use of

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear exp ...

s for mining, cratering, and other civilian purposes. The radioactive fallout from the test contaminated more US residents than any other nuclear test. The Sedan Crater is the largest human-made crater in the United States and is listed on the

National Register of Historic Places The National Register of Historic Places (NRHP) is the Federal government of the United States, United States federal government's official United States National Register of Historic Places listings, list of sites, buildings, structures, Hist ...

Effects

Sedan was a

thermonuclear device A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lowe ...

with a fission yield less than 30% and a fusion yield about 70%.Information sign at the crater: Nevada Test Site - Sedan Crater - 4

''United States Nuclear Tests''; July 1945 through September 1992, DOE/NV--209-REV 15 December 2000, p. xv. According to Carey Sublette, the design of the Sedan device was similar to that used in the Bluestone and Swanee tests of

Operation Dominic Operation Dominic was a series of 31 nuclear test explosions ("shots") with a total yield conducted in 1962 by the United States in the Pacific. This test series was scheduled quickly, in order to respond in kind to the Soviet resumption of t ...

conducted days and months prior to Sedan respectively, and was therefore not unlike the W56 high yield

Minuteman I The LGM-30 Minuteman is an American land-based intercontinental ballistic missile (ICBM) in service with the Air Force Global Strike Command. , the LGM-30G (Version 3) is the only land-based ICBM in service in the United States and represents th ...

missile warhead. The device had a diameter of , a length of , and a weight of . The timing of the test put it within the

Operation Storax Operation Storax was a series of 47 nuclear tests conducted by the United States in 1962–1963 at the Nevada Test Site. These tests followed the ''Operation Fishbowl'' series and preceded the ''Operation Roller Coaster'' series. British test ...

fiscal year, but Sedan was functionally part of

, and the test protocol was sponsored and conducted by

Lawrence Livermore National Laboratory Lawrence Livermore National Laboratory (LLNL) is a Federally funded research and development centers, federally funded research and development center in Livermore, California, United States. Originally established in 1952, the laboratory now i ...

with minimal involvement by the

United States Department of Defense The United States Department of Defense (DoD, USDOD, or DOD) is an United States federal executive departments, executive department of the federal government of the United States, U.S. federal government charged with coordinating and superv ...

. The explosive device was lowered into a shaft drilled into the desert

alluvium Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...

deep. The fusion-fission blast had a yield equivalent to 104

kiloton TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. A ton of TNT equivalent is a unit of energy defined by convention to be (). It is the approximate energy released in the det ...

s of

TNT Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps ...

(435

terajoule The joule ( , or ; symbol: J) is the unit of energy in the International System of Units (SI). In terms of SI base units, one joule corresponds to one kilogram- metre squared per second squared One joule is equal to the amount of work done ...

s) and lifted a dome of earth above the desert floor before it vented at three seconds after detonation, exploding upward and outward displacing of soil.

Sedan Crater

The resulting crater is deep with a diameter of about . A circular area of the desert floor five miles across was obscured by fast-expanding dust clouds moving out horizontally from the base surge, akin to

pyroclastic surge A pyroclastic surge is a fluidised mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes i ...

. The blast caused seismic waves equivalent to an earthquake of 4.75 on the

Richter scale The Richter scale (), also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and pr ...

. The radiation level on the crater lip at 1 hour after the burst was 500 R per hour (130 mC/(kg·h)),Information sign at the crater: Nevada Test Site - Sedan Crater - 1

but it dropped to 500 mR per hour after 27 days. Within 7 months (~210 days) of the excavation, the bottom of the crater could be safely walked upon with no protective clothing, with radiation levels at 35 mR per hour after 167 days. Over 10,000 people per yearNevada Test Site History. ''Sedan Crater''
visit the crater through free monthly tours offered by the

U.S. Department of Energy The United States Department of Energy (DOE) is an executive department of the U.S. federal government that oversees U.S. national energy policy and energy production, the research and development of nuclear power, the military's nuclear we ...

National Nuclear Security Administration The National Nuclear Security Administration (NNSA) is a United States federal agency responsible for safeguarding national security through the military application of nuclear science. NNSA maintains and enhances the safety, security, and ef ...

Nevada Site Office. The crater was listed on the

on March 21, 1994.

Salsola tragus ''Salsola tragus'', often known by its synonym is a species of flowering plant in the family Amaranthaceae. It is known by various Common name, common names such as prickly Russian thistle, windwitch, or common saltwort. It is widely known simp ...

, also known as tumbleweed, is the primary plant species growing in the crater along with some grasses. Analysis in 1993 observed that the original perennial shrubs once living there had shown no recovery.

Statistics

* Maximum depthNevada Test Site History. ''Sedan Crater''
* Maximum diameter * VolumeProject Sedan, On-Site Radiological Safety Report
/ref> * Weight of material lifted * Maximum lip height * Minimum lip height

Fallout

The explosion caused two plumes of radioactive cloud, rising to 3.0 km and 4.9 km (10,000 ft and 16,000 ft). The plumes headed northeast and then east in roughly parallel paths towards the Atlantic Ocean.

Nuclear fallout Nuclear fallout is residual radioactive material that is created by the reactions producing a nuclear explosion. It is initially present in the mushroom cloud, radioactive cloud created by the explosion, and "falls out" of the cloud as it is ...

was dropped through several counties. Detected radioactivity was especially high in eight counties in Iowa and one county each in Nebraska, South Dakota and Illinois. The most heavily affected counties were

Howard Howard is a masculine given name derived from the English surname Howard. ''The Oxford Dictionary of English Christian Names'' notes that "the use of this surname as a christian name is quite recent and there seems to be no particular reason for ...

, Mitchell and Worth counties in Iowa as well as Washabaugh County in South Dakota. The average estimated fallout from Sedan on Howard, Mitchell and Worth counties was 950 microcuries each, while Washabaugh County received an estimated average of 860 microcuries of fallout. The explosion created fallout that affected more US residents than any other nuclear test, exposing more than 13 million people to radiation. Of all the nuclear tests conducted in the United States, Sedan ranked highest in overall activity of

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ...

s in fallout. The test released 880,000

curie Curie may refer to: *Curie family, a family of distinguished scientists: :* Jacques Curie (1856–1941), French physicist, Pierre's brother :* Pierre Curie (1859–1906), French physicist and Nobel Prize winner, Marie's husband :* Marie Curi ...

s (33 PBq) of radioactive

iodine-131 Iodine-131 (131I, I-131) is an important radioisotope of iodine discovered by Glenn Seaborg and John Livingood in 1938 at the University of California, Berkeley. It has a radioactive decay half-life of about eight days. It is associated with nu ...

, an agent of thyroid disease, into the atmosphere. Sedan ranked first in percentages of these particular radionuclides detected in fallout: ¹⁹⁸Au, ¹⁹⁹Au, ⁷Be, ⁹⁹Mo, ¹⁴⁷Nd, ²⁰³Pb, ¹⁸¹W, ¹⁸⁵W and ¹⁸⁸W. Sedan ranked second in these radionuclides in fallout: ⁵⁷Co, ⁶⁰Co and ⁵⁴Mn. Sedan ranked third in the detected amount of ²⁴Na in fallout. In countrywide deposition of radionuclides, Sedan was highest in the amount of ⁷Be, ⁵⁴Mn, ¹⁰⁶Ru and ²⁴²Cm, and second highest in the amount of deposited ^127mTe. Sedan ranks highest in percentages of ¹⁹⁸Au detected. Sedan's fallout contamination contributed a little under 7% to the total amount of radiation which fell on the US population during all of the nuclear tests at NTS. Sedan's effects were similar to shot "George" of

Operation Tumbler–Snapper Operation Tumbler–Snapper was a series of nuclear weapons tests conducted by the United States in early 1952 at the Nevada Test Site. The ''Tumbler–Snapper'' series of tests followed ''Operation Buster–Jangle'' and preceded ''Operation Iv ...

, detonated on June 1, 1952, which also contributed about 7% to the total radioactive fallout. Uncertainty regarding exact amounts of exposure prevents knowing which of the two nuclear tests caused the most; George is listed as being the highest exposure and Sedan second highest by the

United States Department of Health and Human Services The United States Department of Health and Human Services (HHS) is a cabinet-level executive branch department of the US federal government created to protect the health of the US people and providing essential human services. Its motto is ...

Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...

, and the

National Cancer Institute The National Cancer Institute (NCI) coordinates the United States National Cancer Program and is part of the National Institutes of Health (NIH), which is one of eleven agencies that are part of the U.S. Department of Health and Human Services. ...

. Had this test been conducted after 1965 when improvements in device design were realized, achieving a 100-fold reduction in radiation release is considered feasible.

Conclusions

The Plowshare project developed the Sedan test in order to determine the feasibility of using nuclear detonations to quickly and economically excavate large amounts of earth and rock. Proposed applications included the creation of harbors, canals, open pit mines, railroad and highway cuts through mountainous terrain and the construction of dams. Assessment of the full effects of the Sedan shot showed that the radioactive fallout from such uses would be extensive. Public concerns about the health effects and a lack of political support eventually led to abandonment of the concept. No such nuclear excavation has since been undertaken by the United States, though the Soviet Union continued to pursue the concept through their program

Nuclear Explosions for the National Economy Nuclear Explosions for the National Economy (; sometimes referred to as ''Program #7'') was a Soviet program to investigate peaceful nuclear explosions (''PNEs''). It was analogous to the United States program '' Operation Plowshare'', although t ...

, particularly with their 140 kiloton

Chagan (nuclear test) Chagan may refer to: Places * Chagan (closed city), an abandoned closed city in Kazakhstan, currently a ghost town * Chagan, Da'an, Jilin (叉干镇), a town in Da'an, Jilin Da'an () is a city of northwestern Jilin province in Northeast China, ...

, which created an artificial lake reservoir (see Lake Chagan).

Diplomatic issue with Sudan

On March 2, 2005,

Ellen Tauscher Ellen O'Kane Tauscher (November 15, 1951 – April 29, 2019) was an American businesswoman, diplomat, and Democratic Party politician who was the U.S. representative for California's 10th congressional district from 1997 to 2009. From 2009 to 20 ...

, a Democratic member of the

U.S. House of Representatives The United States House of Representatives is a chamber of the bicameral United States Congress; it is the lower house, with the U.S. Senate being the upper house. Together, the House and Senate have the authority under Article One of th ...

from

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, used Sedan as an example of a test which produced a considerable amount of radioactive

fallout Nuclear fallout is residual radioactive material that is created by the reactions producing a nuclear explosion. It is initially present in the radioactive cloud created by the explosion, and "falls out" of the cloud as it is moved by the ...

while giving congressional testimony on the containment of debris from nuclear testing. However, the name "Sedan" was incorrectly transcribed as "

Sudan Sudan, officially the Republic of the Sudan, is a country in Northeast Africa. It borders the Central African Republic to the southwest, Chad to the west, Libya to the northwest, Egypt to the north, the Red Sea to the east, Eritrea and Ethiopi ...

" in the ''

Congressional Record The ''Congressional Record'' is the official record of the proceedings and debates of the United States Congress, published by the United States Government Publishing Office and issued when Congress is in session. The Congressional Record Ind ...

''. Within days of the error, the international community took notice. Sudanese officials responded by stating that "the Sudanese government takes this issue seriously and with extreme importance". The Chinese Xinhua General News Service published an article claiming that the Sudanese government blamed the U.S. for raising

cancer Cancer is a group of diseases involving Cell growth#Disorders, abnormal cell growth with the potential to Invasion (cancer), invade or Metastasis, spread to other parts of the body. These contrast with benign tumors, which do not spread. Po ...

rates among the Sudanese people. Despite the U.S. embassy in

Khartoum Khartoum or Khartum is the capital city of Sudan as well as Khartoum State. With an estimated population of 7.1 million people, Greater Khartoum is the largest urban area in Sudan. Khartoum is located at the confluence of the White Nile – flo ...

issuing a statement clarifying that it was a typographic error, Mustafa Osman Ismail, the Sudanese Foreign Minister, stated his government would continue investigating the claims.

References

External links

US government movie about the Sedan test

Virtual-Reality tour of Sedan Site

Sedan Crater
at the Online Nevada Encyclopedia
Sedan Nuclear Test – Original Military Film – YouTube

Nevada National Security Site History – Sedan Crater (PDF)

The Nuclear Sedan Crater of Nevada
{{Nevada State Historic Places/Nye 1962 in military history 1962 in Nevada 1962 in the United States Diplomatic incidents Explosion craters Explosions in 1962 History of Nye County, Nevada July 1962 in the United States National Register of Historic Places in Nye County, Nevada Nevada Test Site nuclear explosive tests Nuclear history of the United States Peaceful nuclear explosions Project Plowshare nuclear tests Tourist attractions in Nye County, Nevada Underground nuclear weapons testing