Sedan (nuclear test)
Encyclopedia
Storax Sedan was a shallow underground nuclear test
conducted in Area 10 of Yucca Flat
at the Nevada National Security Site on 6 July 1962 as part of Operation Plowshare
, a program to investigate the use of nuclear weapon
s for mining, cratering, and other civilian purposes. The radioactive fallout from the test contaminated more US residents than any other nuclear test, and the Sedan Crater
is the largest man-made crater in the United States, and is listed on the National Register of Historic Places
.
Sedan was a thermonuclear device with a fission yield less than 30% and a fusion yield about 70%. The timing of the test put it within the Operation Storax
fiscal year, but Sedan was functionally part of Operation Plowshare, and the test protocol was sponsored and conducted by Lawrence Livermore National Laboratory
with minimal involvement by the United States Department of Defense
. The explosive device was lowered into a shaft drilled into the desert alluvium 194 m (636.5 ft) deep. The fusion-fission blast had a yield equivalent to 104 kilotons of TNT
(435 terajoules) and lifted a dome of earth 290 feet (90 m) above the desert floor before it vented at three seconds after detonation, exploding upward and outward displacing more than 11000000 t (10,826,238.9 LT) of soil. The resulting crater is 100 m (328.1 ft) deep with a diameter of about 390 m (1,279.5 ft). 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
. The blast caused seismic waves equivalent to an earthquake of 4.75 on the Richter scale
. The radiation level on the crater lip at 1 hour after burst was 500 R
per hour (130 mC/(kg·h)).
was dropped along the way, narrowly dispersed in a relatively small number of United States counties. Detected radioactivity was especially high in eight counties in Iowa and one county each in Nebraska, South Dakota and Illinois. Most heavily affected counties were Howard
, Mitchell
and Worth
counties in Iowa, as well as Washabaugh County in South Dakota, an area that has since been incorporated into Jackson County
and is wholly within Pine Ridge Indian Reservation
. These four counties measured maximum levels higher than 6,000 microcurie
s per square meter (220 MBq/m2).
Of all the nuclear tests conducted in the USA, Sedan ranked highest in overall activity of radionuclide
s in fallout. The test released 880,000 curie
s (33 PBq) of radioactive iodine-131
, 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's fallout contamination contributed a little under 7% to the total amount of radiation which fell on the U.S. population during all of the nuclear tests at NTS. Sedan's effects were similar to shot "George" of Operation Tumbler-Snapper
, 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 was the most; George is listed as being the highest exposure and Sedan second highest by the United States Department of Health and Human Services
, Centers for Disease Control and Prevention
, and the National Cancer Institute
.
.
, a Californian
Democratic member of the U.S. House of Representatives
, used Sedan as an example of a test which produced a considerable amount of radioactive fallout
while giving congressional testimony on the containment of debris from nuclear testing. However the word Sedan was incorrectly transcribed as the country Sudan
in the Congressional Record
.
Within days of the error, the international community took notice. Sudanese officials responded to the mistake by stating that "the Sudanese government takes this issue seriously and with extreme importance". The Xinhua General News Service in China
even published an article claiming that the Sudanese government blamed the U.S. for raising cancer
rates among the Sudanese people. Despite the U.S. embassy in Khartoum 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.
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...
conducted in Area 10 of Yucca Flat
Yucca Flat
Yucca Flat is a closed desert drainage basin, one of four major nuclear test regions within the Nevada Test Site , 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, about ten miles north of Frenchman Flat, and from Las...
at the Nevada National Security Site on 6 July 1962 as part of Operation Plowshare
Operation Plowshare
Project Plowshare was the overall United States term for the development of techniques to use nuclear explosives for peaceful construction purposes...
, a program to investigate the use of nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...
s for mining, cratering, and other civilian purposes. The radioactive fallout from the test contaminated more US residents than any other nuclear test, and the Sedan Crater
Sedan Crater
Sedan Crater is the result of the Sedan nuclear test and is located within the Nevada Test Site. The crater was listed on the National Register of Historic Places on March 21, 1994. The crater is a man-made object that can be seen from earth orbit with the unaided eye.The crater is the result of...
is the largest man-made crater in the United States, and is listed on the National Register of Historic Places
National Register of Historic Places
The National Register of Historic Places is the United States government's official list of districts, sites, buildings, structures, and objects deemed worthy of preservation...
.
Effects
Operation Storax
Operation Storax was a series of 48 American nuclear tests which took place in 1962 and 1963, including the Sedan blast, which was part of the Plowshare program.The individual blasts were: NameDateSize SEDAN July 6 104 kilotons...
fiscal year, but Sedan was functionally part of Operation Plowshare, and the test protocol was sponsored and conducted by Lawrence Livermore National Laboratory
Lawrence Livermore National Laboratory
The Lawrence Livermore National Laboratory , just outside Livermore, California, is a Federally Funded Research and Development Center founded by the University of California in 1952...
with minimal involvement by the United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
. The explosive device was lowered into a shaft drilled into the desert alluvium 194 m (636.5 ft) deep. The fusion-fission blast had a yield equivalent to 104 kilotons of TNT
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...
(435 terajoules) and lifted a dome of earth 290 feet (90 m) above the desert floor before it vented at three seconds after detonation, exploding upward and outward displacing more than 11000000 t (10,826,238.9 LT) of soil. The resulting crater is 100 m (328.1 ft) deep with a diameter of about 390 m (1,279.5 ft). 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
Pyroclastic surge
A pyroclastic surge is a fluidized mass of turbulent gas and rock fragments which is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher proportion of gas to rock ratio, which makes it more turbulent and allows it to rise...
. The blast caused seismic waves equivalent to an earthquake of 4.75 on the Richter scale
Richter magnitude scale
The expression Richter magnitude scale refers to a number of ways to assign a single number to quantify the energy contained in an earthquake....
. The radiation level on the crater lip at 1 hour after burst was 500 R
Röntgen
The roentgen is a unit of measurement for exposure to ionizing radiation , and is named after the German physicist Wilhelm Röntgen...
per hour (130 mC/(kg·h)).
Fallout
The Sedan shot resulted in a radioactive cloud that separated into two plumes, rising to 3.0 km and 4.9 km (10,000 ft and 16,000 ft). The two plumes headed northeast and then east in roughly parallel paths towards the Atlantic Ocean. A large amount of nuclear falloutNuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...
was dropped along the way, narrowly dispersed in a relatively small number of United States counties. Detected radioactivity was especially high in eight counties in Iowa and one county each in Nebraska, South Dakota and Illinois. Most heavily affected counties were Howard
Howard County, Iowa
-2010 census:The 2010 census recorded a population of 9,566 in the county, with a population density of . There were 4,367 housing units, of which 3,944 were occupied.-2000 census:...
, Mitchell
Mitchell County, Iowa
-2010 census:The 2010 census recorded a population of 10,776 in the county, with a population density of . There were 4,850 housing units, of which 4,395 were occupied.-2000 census:According to the U.S...
and Worth
Worth County, Iowa
-2010 census:The 2010 census recorded a population of 7,598 in the county, with a population density of . There were 3,548 housing units, of which 3,172 were occupied.-2000 census:...
counties in Iowa, as well as Washabaugh County in South Dakota, an area that has since been incorporated into Jackson County
Jackson County, South Dakota
As of the census of 2000, there were 2,930 people, 945 households, and 675 families residing in the county. The population density was 2 people per square mile . There were 1,173 housing units at an average density of 1 per square mile...
and is wholly within Pine Ridge Indian Reservation
Pine Ridge Indian Reservation
The Pine Ridge Indian Reservation is an Oglala Sioux Native American reservation located in the U.S. state of South Dakota. Originally included within the territory of the Great Sioux Reservation, Pine Ridge was established in 1889 in the southwest corner of South Dakota on the Nebraska border...
. These four counties measured maximum levels higher than 6,000 microcurie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
s per square meter (220 MBq/m2).
Of all the nuclear tests conducted in the USA, Sedan ranked highest in overall activity of radionuclide
Radionuclide
A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma...
s in fallout. The test released 880,000 curie
Curie
The curie is a unit of radioactivity, defined asThis is roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers of radiology, Marie and Pierre Curie, for whom the unit was named. In addition to the curie, activity can be measured using an SI derived unit,...
s (33 PBq) of radioactive iodine-131
Iodine-131
Iodine-131 , also called radioiodine , is an important radioisotope of iodine. It has a radioactive decay half-life of about eight days. Its uses are mostly medical and pharmaceutical...
, an agent of thyroid disease, into the atmosphere. Sedan ranked first in percentages of these particular radionuclides detected in fallout: 198Au
Isotopes of gold
Gold has one stable isotope, 197Au, and 36 radioisotopes with 195Au being the most stable with a half-life of 186 days.Gold is currently considered the heaviest Monoisotopic element .Gold has been proposed as a material for creating a salted nuclear weapon Gold (Au) has one stable isotope, 197Au,...
, 199Au
Isotopes of gold
Gold has one stable isotope, 197Au, and 36 radioisotopes with 195Au being the most stable with a half-life of 186 days.Gold is currently considered the heaviest Monoisotopic element .Gold has been proposed as a material for creating a salted nuclear weapon Gold (Au) has one stable isotope, 197Au,...
, 7Be
Isotopes of beryllium
Although beryllium has 12 known isotopes, only one of these isotopes is stable and a primordial nuclide. As such, it is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low...
, 99Mo
Isotopes of molybdenum
There are 33 known isotopes of molybdenum ranging in atomic mass from 83 to 115, as well as four metastable nuclear isomers. Seven isotopes occur naturally, with atomic masses of 92, 94, 95, 96, 97, 98, and 100. Of these naturally occurring isotopes, six have never been observed to decay, but all...
, 147Nd
Isotopes of neodymium
Naturally occurring neodymium is composed of 5 stable isotopes, 142Nd, 143Nd, 145Nd, 146Nd and 148Nd, with 142Nd being the most abundant , and 2 radioisotopes, 144Nd and 150Nd...
, 203Pb
Isotopes of lead
Lead has four stable isotopes: 204Pb, 206Pb, 207Pb, 208Pb. Lead-204 is entirely a primordial nuclide and is not a radiogenic nuclide. The three isotopes lead-206, lead-207, and lead-208 represent the ends of three decay chains called the uranium series , the actinium series, and the thorium...
, 181W
Isotopes of tungsten
Naturally occurring tungsten consists of four stable isotopes and one isotope, 180W, with an extremely long half-life of 1.8 ± 0.2 Ea...
, 185W
Isotopes of tungsten
Naturally occurring tungsten consists of four stable isotopes and one isotope, 180W, with an extremely long half-life of 1.8 ± 0.2 Ea...
and 188W
Isotopes of tungsten
Naturally occurring tungsten consists of four stable isotopes and one isotope, 180W, with an extremely long half-life of 1.8 ± 0.2 Ea...
. Sedan ranked second in these radionuclides in fallout: 57Co
Isotopes of cobalt
Naturally occurring cobalt is composed of 1 stable isotope, 59Co. 28 radioisotopes have been characterized with the most stable being 60Co with a half-life of 5.2714 years, 57Co with a half-life of 271.79 days, 56Co with a half-life of 77.27 days, and 58Co with a half-life of 70.86 days...
, 60Co
Cobalt-60
Cobalt-60, , is a synthetic radioactive isotope of cobalt. Due to its half-life of 5.27 years, is not found in nature. It is produced artificially by neutron activation of . decays by beta decay to the stable isotope nickel-60...
and 54Mn
Isotopes of manganese
Naturally occurring manganese is composed of 1 stable isotope; 55Mn. 25 radioisotopes have been characterized with the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days...
. Sedan ranked third in the detected amount of 24Na
Isotopes of sodium
There are twenty recognized isotopes of sodium ranging from 18Na to 37Na and two isomers . 23Na is the only stable isotope. As such, it is considered a monoisotopic element and it has a standard atomic mass: 22.98976928 u. Sodium has two radioactive cosmogenic isotopes...
in fallout. In countrywide deposition of radionuclides, Sedan was highest in the amount of 7Be
Isotopes of beryllium
Although beryllium has 12 known isotopes, only one of these isotopes is stable and a primordial nuclide. As such, it is considered a monoisotopic element. It is also a mononuclidic element, because its other isotopes are short-lived that none are primordial and their abundance is very low...
, 54Mn
Isotopes of manganese
Naturally occurring manganese is composed of 1 stable isotope; 55Mn. 25 radioisotopes have been characterized with the most stable being 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.3 days, and 52Mn with a half-life of 5.591 days...
, 106Ru
Isotopes of ruthenium
Naturally occurring ruthenium is composed of seven stable isotopes. Additionally, 27 radioactive isotopes have been discovered. Of these radioisotopes, the most stable are 106Ru with a half-life of 373.59 days, 103Ru with a half-life of 39.26 days and 97Ru with a half-life of 2.9 days.Twenty-four...
and 242Cm
Isotopes of curium
Curium is an artificial element, and thus a standard atomic mass cannot be given. Like all artificial elements, it has no stable isotopes. The first isotope synthesized was 242Cm in 1944....
, and second highest in the amount of deposited 127mTe
Isotopes of tellurium
There are 38 known isotopes and 17 nuclear isomers of tellurium with atomic masses that range from 105 to 142. These are listed in the table below.Naturally occurring tellurium on Earth consists of eight isotopes...
.
Sedan's fallout contamination contributed a little under 7% to the total amount of radiation which fell on the U.S. population during all of the nuclear tests at NTS. Sedan's effects were similar to shot "George" of Operation Tumbler-Snapper
Operation Tumbler-Snapper
Operation Tumbler-Snapper was a series of atomic 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 Ivy....
, 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 was the most; George is listed as being the highest exposure and Sedan second highest by the United States Department of Health and Human Services
United States Department of Health and Human Services
The United States Department of Health and Human Services is a Cabinet department of the United States government with the goal of protecting the health of all Americans and providing essential human services. Its motto is "Improving the health, safety, and well-being of America"...
, Centers for Disease Control and Prevention
Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention are a United States federal agency under the Department of Health and Human Services headquartered in Druid Hills, unincorporated DeKalb County, Georgia, in Greater Atlanta...
, and the National Cancer Institute
National Cancer Institute
The National Cancer Institute is part of the National Institutes of Health , which is one of 11 agencies that are part of the U.S. Department of Health and Human Services. The NCI coordinates the U.S...
.
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 dirt 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 US, though the Soviet Union continued to pursue the concept through their program Nuclear Explosions for the National EconomyNuclear Explosions for the National Economy
Nuclear Explosions for the National Economy , was a Soviet program to investigate peaceful nuclear explosions . It was analogous to the US program Operation Plowshare....
.
Diplomatic issue with Sudan
On March 2, 2005 Ellen TauscherEllen Tauscher
Ellen O'Kane Tauscher is an American politician and Under Secretary of State for Arms Control and International Security Affairs...
, a Californian
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
Democratic member of the U.S. House of Representatives
United States House of Representatives
The United States House of Representatives is one of the two Houses of the United States Congress, the bicameral legislature which also includes the Senate.The composition and powers of the House are established in Article One of the Constitution...
, used Sedan as an example of a test which produced a considerable amount of radioactive fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...
while giving congressional testimony on the containment of debris from nuclear testing. However the word Sedan was incorrectly transcribed as the country Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
in the Congressional Record
Congressional Record
The Congressional Record is the official record of the proceedings and debates of the United States Congress. It is published by the United States Government Printing Office, and is issued daily when the United States Congress is in session. Indexes are issued approximately every two weeks...
.
Within days of the error, the international community took notice. Sudanese officials responded to the mistake by stating that "the Sudanese government takes this issue seriously and with extreme importance". The Xinhua General News Service in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
even published an article claiming that the Sudanese government blamed the U.S. for raising cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
rates among the Sudanese people. Despite the U.S. embassy in Khartoum 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.
External links
- US government movie about the Sedan test
- Sedan Underground Nuclear Test video
- Virtual-Reality tour of Sedan Site
- Sedan Crater at the Online Nevada Encyclopedia