The timeline includes summaries of the major cases of seizures of diverted weapons-usable nuclear materials to date. For our purposes, weapons-useable material is defined as either plutonium 239 or uranium enriched to at least 20% U235. The RAND Corporation estimates that 5 kg of plutonium or 15 kg of 90% HEU are required to make a primitive bomb in the kiloton range. At lower levels of enrichment, far greater quantities would be necessary to build a bomb.
In addition to the nuclear material seizures listed below, the timeline also includes new information uncovered by FRONTLINE's investigation which details the behind-the-scenes activity leading up to some of the arrests. Most of these details are presented publicly for the first time on this web site.
A distinction must be made between the great variety of radioactive isotopes and fissile materials (such as uranium 235 and plutonium 239). Fissile materials have the unique property of releasing several neutrons when 1heir atom is struck by one neutron and splits. This property can fuel a chain reaction when there is enough in one place, an amount called a critical mass. Because energy is released each time the atom splits, this exponential chain reaction of energy release can quite quickly result in a nuclear explosion under the right conditions.
Radioactive materials cannot be used to cause such atomic explosions. But because they decay
over time and release particles which can damage living tissue, they pose a hazard in and of themselves. In fact, most of the black market activity over the past few years has involved various radioactive substances and not fissile materials. Those who downplay the risk of illicit trade in nuclear weapons materials argue that almost all of the hundreds of cases of nuclear contraband so far have involved radioactive junk. While factually true, this does not mean that the radioactive materials themselves are not dangerous. Moreover, as the cases listed in this timeline show, there have been enough incidents to show that it is possible for nuclear weapons materials to reach the black market as well.
Click on the timeline for more information about a particular event.
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