A Radiological Dispersion Device (RDD) combines a conventional explosive device with radioactive material. Use of an RDD or “dirty bomb” is considered to be more likely used by terrorists rather than nuclear explosive devices. RDDs require limited technical knowledge to build and deploy compared to a nuclear device.
The size of the affected area and the level of destruction caused by an RDD depends on the level of sophistication and size of the conventional bomb, type of radioactive material used, quality and quantity of the radioactive material, local meteorological conditions (primarily wind and precipitation) and speed at which the area of the RDD detonation was evacuated. The area affected could be placed off-limits to the public for several months during cleanup efforts.
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