There is a huge range of possible dirty bomb designs. Different explosive materials, applied in different quantities, would generate explosions of varying sizes, and different types and quantities of radioactive material would contaminate an area to different degrees. Some designs include:
- A small bomb, consisting of one stick of dynamite and a very small amount of radioactive material
- A medium-size bomb, such as a backpack or small car filled with explosives and a greater amount of radioactive material
- A large bomb, such as a truck filled with explosives and a good amount of radioactive material
The builders of these bombs wouldn't have much trouble getting their hands on high explosives -- dynamite is readily available, and TNT isn't too hard to come by. The main limitation on the bomb would be the available radioactive material.
It's not nearly as accessible as explosive material, but there are a number of sources for radioactive material around the world. For example:
- Hospitals use small quantities of radioactive material, such as cesium-137, in nuclear medicine.
- Universities use similar materials to conduct scientific research.
- Food irradiation plants use radiation from cobalt-60 to kill harmful bacteria on food. (See CDC: Frequently Asked Questions about Food Irradiation for more information.)
- Natural radioactive uranium isotopes are mined for use in nuclear energy. Terrorists could conceivably acquire uranium from various mines in Africa.
- There are a number of abandoned "nuclear batteries" scattered around the former Soviet Union. These portable thermoelectric generators contain a sizable amount of strontium-90, a highly potent radioactive isotope. (Check out Makings of a 'Dirty Bomb' for more information.)
- People could also collect spent radioactive fuel from Russian reactors, which have been abandoned in old nuclear submarines, among other places.
- They could also put something together using various low-level radioactive materials available to anybody, such as the radioactive material in smoke alarms. Tale of the Radioactive Boy Scout is good evidence that this is a very real possibility.
The big question, of course, is what would actually happen if someone set off a bomb containing any of this material. As it turns out, there isn't a clear answer. Ask 10 different experts and you'll probably get 10 slightly different answers. In the next section, we'll explore the various possible scenarios.