Cobalt bomb A cobalt bomb is a theoretical 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 . He suggested that an arsenal of cobalt bombs would be capable of destroying all human life on Earth ( though his conclusions are disputed ) . As far as is publicly known , no cobalt bombs have ever been built . 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 . Mechanism . A cobalt bomb could be made by placing a quantity of ordinary cobalt metal ( Co ) inside a nuclear bomb . When the bomb explodes , the neutrons produced by the explosion would transmute the cobalt to the radioactive isotope cobalt - 60 ( Co ) , 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 Ni . The nickel nucleus is activated , and emits two gamma rays with energies of 1 . 17 and 1 . 33 MeV , hence the overall nuclear equation of the reaction is : Nickel - 60 is a stable isotope and undergoes no further decays after emitting the gamma rays . The 5 . 27 year half life of the Co is long enough to allow it to settle out before significant decay has occurred , and for it to be impractical to wait in shelters for it to decay , yet short enough that intense radiation is produced . 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 . In a fission bomb , it has been suggested , the weapon ' s tamper could be made of cobalt . In a fusion bomb the radiation case around the weapon , normally made of U , could be made of cobalt . These changes would reduce the explosive power ( yield ) of the weapon somewhat . Example of radiation levels vs . time . Assume a cobalt bomb deposits intense fallout causing a dose rate of 10 sievert s ( 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 . After one half - life of 5 . 27 years , only half of the Cobalt - 60 will have decayed , and the dose rate in the affected area would be 5 Sv / hour . At this dose rate , a person exposed to the radiation would receive a lethal dose in 1 hour . After 10 half - lives ( about 53 years ) , the dose rate would have decayed to around 10 mSv / hour . At this point , a healthy person could spend 1 to 4 days exposed to the fallout with no immediate effects . After 20 half - lives ( about 105 years ) , the dose rate would have decayed to around 10 μSv / hour . At this stage , humans could remain unsheltered full - time since their yearly radiation dose would be about 80 mSv . However , this yearly dose rate is on the order of 30 times greater than the peacetime exposure rate of 2 . 5 mSv / year . As a result , the rate of cancer incidence in the survivor population would likely increase . After 27 half - lives ( about 142 years ) , the dose rate from Cobalt - 60 would have decayed to less than 1 mSv / year and could be considered negligible . Cultural references . The concept of cobalt bombs has been used in a number of works of apocalyptic fiction . The 1954 science fiction short story " Exhibit Piece " by Philip K . Dick ends with the newspaper headline " RUSSIA REVEALS COBALT BOMB ; TOTAL WORLD DESTRUCTION AHEAD " . In the 1957 novel " On the Beach " by Nevil Shute ( and the films based on it ) , the death of all humanity is brought about by the detonation of cobalt bombs in the Northern Hemisphere . In the 1964 film " Dr . Strangelove " , the Soviet Union had established a secret nuclear deterrent comprising 50 buried cobalt bombs . The concept was also used in some other works of fiction at well . A cobalt and iodine " atomic device " is supplied by the Chinese Communist government to Auric Goldfinger in the 1964 James Bond film " Goldfinger " , where he intends to detonate the bomb inside Fort Knox , rendering the USA ' s gold bullion reserves radioactive for 58 years . Paul Erdman ' s 1976 novel " The Crash of ' 79 " includes Iran using cobalt bombs to attack Middle East oilfields , rendering them " totally inaccessible for at least twenty - five years " . The mutant human New Yorkers in " Beneath the Planet of the Apes " pray to an " alpha - omega " bomb , which Colonel Taylor explains to Brent is a doomsday weapon with a cobalt casing ; Taylor detonates the bomb at the end of the film , after which a narrator states that the planet ' is now dead ' . Two millennia earlier , in " Battle for the Planet of the Apes " , Governor Kolp had ordered Méndez to detonate the bomb if he and his troops failed to return from their mission to destroy the ape village ; instead , Méndez created a religion around the bomb .