HOME
        TheInfoList






A cobalt bomb is a type of "salted bomb": a nuclear weapon designed to produce enhanced amounts of radioactive fallout, intended to contaminate a large area with radioactive material. The concept of a cobalt bomb was originally described in a radio program by physicist Leó Szilárd on February 26, 1950.[1] His intent was not to propose that such a weapon be built, but to show that nuclear weapon technology would soon reach the point where it could end human life on Earth, a doomsday device.[2][3] Such "salted" weapons were requested by the U.S. Air Force and seriously investigated, but not deployed.[citation needed] In the 1964 edition of the U.S. Department of Defense book The Effects of Nuclear Weapons, a new section titled radiological warfare clarified the "Doomsday device" issue.[4]

The Russian Federation has allegedly developed cobalt warheads for use with their Status-6 Oceanic Multipurpose System nuclear torpedoes.[5][6][7] However many commentators doubt that this is a real project, and see it as more likely to be a staged leak to intimidate the United States. Amongst other comments on it, Edward Moore Geist wrote a paper in which he says that "Russian decision makers would have little confidence that these areas would be in the intended locations"[8] and Russian military experts are cited as saying that "robotic torpedoes could have other purposes, such as delivering deep-sea equipment or installing surveillance devices."[9]

The Operation Antler/Round 1 test by the British at the Tadje site in the Maralinga range in Australia on September 14, 1957, tested a bomb using cobalt pellets as a radiochemical tracer for estimating yield. This was considered a failure and the experiment was not repeated.[10] In Russia, the triple "taiga" nuclear salvo test, as part of the preliminary March 1971 Pechora–Kama Canal project, produced relatively high amounts of cobalt-60 (60Co or Co-60) from the steel that surrounded the Taiga devices, with this fusion generated neutron activation product being responsible for about half of the gamma dose now (2011) at the test site. This high percentage contribution is largely because the devices did not rely much at all on fission reactions and thus the quantity of gamma emitting caesium-137 fallout is therefore comparatively low. Photosynthesizing vegetation exists all around the lake that was formed.[11][12]

Mechanism

A cobalt bomb could be made by placing a quantity of ordinary cobalt metal (59Co) around a thermonuclear bomb. When the bomb explodes, the neutrons produced by the fusion reaction in the secondary stage of the thermonuclear bomb's explosion would transmute the cobalt to the radioactive cobalt-60, which would be vaporized by the explosion. The cobalt would then condense and fall back to Earth with the dust and debris from the explosion, contaminating the ground.

The deposited cobalt-60 would have a half-life of 5.27 years, decaying into 60Ni and emitting two gamma rays with energies of 1.17 and 1.33 MeV, hence the overall nuclear equation of the reaction is:

59
27
Co
+ n → 60
27
Co
60
28
Ni
+ e + gamma rays.

Nickel-60 is a stable isotope and undergoes no further decays after emitting the gamma rays.

The 5.27 year half life of the 60Co is long enough to allow it to settle out before significant decay has occurred, and to render it impractical to wait in shelters for it to decay, yet short enough that intense radiation is produced.[10] Many isotopes are more radioactive (gold-198, tantalum-182, zinc-65, sodium-24, and many more), but they would decay faster, possibly allowing some population to survive in shelters.

Fallout from cobalt bombs vs. other nuclear weapons

Fission products are more deadly than neutron-activated cobalt in the first few weeks following detonation. After one to six months, the fission products from even a large-yield thermonuclear weapon decay to levels tolerable by humans. The large-yield two-stage (a fission trigger/primary with a fusion–fission secondary) thermonuclear weapon is thus automatically a weapon of radiological warfare, but its fallout decays much more rapidly than that of a cobalt bomb. A cobalt bomb's fallout on the other hand would render affected areas effectively stuck in this interim state for decades: habitable, but not safe for constant habitation.

Initially, gamma radiation from the fission products of an equivalent size fission-fusion-fission bomb are much more intense than Co-60: 15,000 times more intense at 1 hour; 35 times more intense at 1 week; 5 times more intense at 1 month; and about equal at 6 months. Thereafter fission product fallout radiation levels drop off rapidly, so that Co-60 fallout is 8 times more intense than fission at 1 year and 150 times more intense at 5 years. The very long-lived isotopes produced by fission would overtake the 60Co again after about 75 years.[13]

Theoretically, a device containing 510 metric tons of Co-59 can spread 1 g of the material to each square km of the Earth's surface (510,000,000 km2). If one assumes that all of the material is converted to Co-60 at 100 percent efficiency and if it is spread evenly across the Earth's surface, it is possible for a single bomb to kill every person on Earth. However, in fact, complete 100% conversion into Co-60 is unlikely; a 1957 British experiment at Maralinga showed that Co-59's neutron absorption ability was much lower than predicted, resulting in a very limited formation of Co-60 isotope in practice.

In addition, another important point in considering the effects o

A cobalt bomb is a type of "salted bomb": a nuclear weapon designed to produce enhanced amounts of radioactive fallout, intended to contaminate a large area with radioactive material. The concept of a cobalt bomb was originally described in a radio program by physicist Leó Szilárd on February 26, 1950.[1] His intent was not to propose that such a weapon be built, but to show that nuclear weapon technology would soon reach the point where it could end human life on Earth, a doomsday device.[2][3] Such "salted" weapons were requested by the U.S. Air Force and seriously investigated, but not deployed.[citation needed] In the 1964 edition of the U.S. Department of Defense book The Effects of Nuclear Weapons, a new section titled radiological warfare clarified the "Doomsday device" issue.[4]

The Russian Federation has allegedly developed cobalt warheads for use with their Status-6 Oceanic Multipurpose System nuclear torpedoes.[5][6][7] However many commentators doubt that this is a real project, and see it as more likely to be a staged leak to intimidate the United States. Amongst other comments on it, Edward Moore Geist wrote a paper in which he says that "Russian decision makers would have little confidence that these areas would be in the intended locations"[8] and Russian military experts are cited as saying that "robotic torpedoes could have other purposes, such as delivering deep-sea equipment or installing surveillance devices."[9]

The Operation Antler/Round 1 test by the British at the Tadje site in the Maralinga range in Australia on September 14, 1957, tested a bomb using cobalt pellets as a radiochemical tracer for estimating yield. This was considered a failure and the experiment was not repeated.[10] In Russia, the triple "taiga" nuclear salvo test, as part of the preliminary March 1971 Pechora–Kama Canal project, produced relatively high amounts of cobalt-60 (60Co or Co-60) from the steel that surrounded the Taiga devices, with this fusion generated neutron activation product being responsible for about half of the gamma dose now (2011) at the test site. This high percentage contribution is largely because the devices did not rely much at all on fission reactions and thus the quantity of gamma emitting caesium-137 fallout is therefore comparatively low. Photosynthesizing vegetation exists all around the lake that was formed.[11][12]

A cobalt bomb could be made by placing a quantity of ordinary cobalt metal (59Co) around a thermonuclear bomb. When the bomb explodes, the neutrons produced by the fusion reaction in the secondary stage of the thermonuclear bomb's explosion would transmute the cobalt to the radioactive cobalt-60, which would be vaporized by the explosion. The cobalt would then condense and fall back to Earth with the dust and debris from the explosion, contaminating the ground.

The deposited cobalt-60 would have a half-life of 5.27 years, decaying into 60Ni and emitting two gamma rays with energies of 1.17 and 1.33 MeV, hence the overall nuclear equation of the reaction is:

59
27
Co
+ n → 60
27
Co
half-life of 5.27 years, decaying into 60Ni and emitting two gamma rays with energies of 1.17 and 1.33 MeV, hence the overall nuclear equation of the reaction is:

59
27
Co
+ n → 60
27
Co
60
28
Ni
+ e + gamma rays.

Nickel-60 is a stable isotope and undergoes no further decays after emitting the gamma rays.

The 5.27 year half life of the 60Co is long enough to allow it to settle out before significant decay has occurred, and to render it impractical to wait in shelters for it to decay, yet short enough that intense radiation is produced.[10] Many isotopes are more radioactive (gold-198, tantalum-182, zinc-65, sodium-24, and many more), but they would decay faster, possibly allowing some population to survive in shelters.

Fission products are more deadly than neutron-activated cobalt in the first few weeks following detonation. After one to six months, the fission products from even a large-yield thermonuclear weapon decay to levels tolerable by humans. The large-yield two-stage (a fission trigger/primary with a fusion–fission secondary) thermonuclear weapon is thus automatically a weapon of radiological warfare, but its fallout decays much more rapidly than that of a cobalt bomb. A cobalt bomb's fallout on the other hand would render affected areas effectively stuck in this interim state for decades: habitable, but not safe for constant habitation.

Initially, gamma radiation from the fission products of an equivalent size fission-fusion-fission bomb are much more intense than Co-60: 15,000 times more intense at 1 hour; 35 times more intense at 1 week; 5 times more intense at 1 month; and about equal at 6 months. Thereafter fission product fallout radiation levels drop off rapidly, so that Co-60 fallout is 8 times more int

Initially, gamma radiation from the fission products of an equivalent size fission-fusion-fission bomb are much more intense than Co-60: 15,000 times more intense at 1 hour; 35 times more intense at 1 week; 5 times more intense at 1 month; and about equal at 6 months. Thereafter fission product fallout radiation levels drop off rapidly, so that Co-60 fallout is 8 times more intense than fission at 1 year and 150 times more intense at 5 years. The very long-lived isotopes produced by fission would overtake the 60Co again after about 75 years.[13]

Theoretically, a device containing 510 metric tons of Co-59 can spread 1 g of the material to each square km of the Earth's surface (510,000,000 km2). If one assumes that all of the material is converted to Co-60 at 100 percent efficiency and if it is spread evenly across the Earth's surface, it is possible for a single bomb to kill every person on Earth. However, in fact, complete 100% conversion into Co-60 is unlikely; a 1957 British experiment at Maralinga showed that Co-59's neutron absorption ability was much lower than predicted, resulting in a very limited formation of Co-60 isotope in practice.

In addition, another important point in considering the effects of cobalt bombs is that deposition of fallout is not even throughout the path downwind from a detonation, so that there are going to be areas relatively unaffected by fallout and places where there is unusually intense fallout, so that the Earth would not be universally rendered lifeless by a cobalt bomb.[14] The fallout and devastation following a nuclear detonation does not scale upwards linearly with the explosive yield (equivalent to tons of TNT). As a result, the concept of "overkill"—the idea that one can simply estimate the destruction and fallout created by a thermonuclear weapon of the size postulated by Leo Szilard's "cobalt bomb" thought experiment by extrapolating from the effects of thermonuclear weapons of smaller yields—is fallacious.[15][dubious ]

Assume a cobalt bomb deposits intense fallout causing a dose rate of 10 sieverts (Sv) per hour. At this dose rate, any unsheltered person exposed to the fallout would receive a lethal dose in about 30 minutes (assuming a median lethal dose of 5 Sv). People in well-built shelters would be safe due to radiation shielding.