"Nuclear terrorism" refers to a number of different ways nuclear materials might be exploited as a terrorist tactic. These include attacking nuclear facilities, purchasing nuclear weapons, or building nuclear weapons or otherwise finding ways to disperse radioactive materials.
- A terrorist attack on a nuclear research facility or commercial nuclear power plant could lead to the release of nuclear material. Additionally, as explained in the British Medical Journal, in 2002, an attack on stores of spent nuclear fuels poses as much, if not more, of an attack risk:
In addition to the reactors themselves, nuclear power plants harbour enormous quantities of radioactive materials in spent fuel pools. On average these spent fuel pools contain five times as much radioactive material as the reactor core, and they are housed in simple corrugated steel buildings even more vulnerable to attack than the reactor containment buildings. The vulnerability of nuclear power plants is highlighted by reports that 47% of US nuclear power plants failed to repel mock terrorist attacks conducted by the Nuclear Regulatory Commission during the 1990s. The results of an attack on either a reactor or a spent fuel pool could equal or exceed the effects of the 1986 Chernobyl disaster, which led to 30 acute deaths from radiation sickness, at least 1800 excess cases of childhood thyroid cancer, the evacuation of 100 000 people, and the radioactive contamination of vast tracts of land in several countries.
A second way extremists could exploit radioactive materials would be by creating a "dirty bomb" by loading a conventional bomb with radioactive materials. They would disperse when the bomb exploded.
Terrorists might be able to purchase existing nuclear weapons on the black market.
Terrorist groups may soon be able to create "improvised nuclear devices" (IND). According to a February 2007 report issued by British think tank Chatham House:
"A so-called Improvised Nuclear Device (IND) could also be produced using much larger quantities of lower-grade, less enriched U-235. The device might then 'fizzle' rather than detonate its entire mass instantly and efficiently. But if the resulting explosion were to be equivalent to just one or a few kilotons of TNT rather than tens of kilotons, terrorists could still find this option attractive."
- It is possible—although so far not highly probable-- that a terrorist group could build a nuclear weapon.
For more terrorist weapons and tactics, see: Glossary of Weapons and Tactics