radiation weapon or radiological weapon, a bomb or warhead that uses conventional chemical explosives to disperse radioactive material, sometimes called a "dirty bomb." Designed to produce radiation sickness in a military force or a civilian population instead of destroy a target, radiation weapons typically consist of a highly radioactive material encased in lead and surrounded by a high explosive. During the 1980s, Iraq developed and tested a radiation weapon that was intended to produce health effects that would be difficult to explain, but decided to abandoned the project because a radiation level low enough to escape detection was also insufficient to cause significant medical problems in the weeks following an attack. See also nuclear weapons.