Dirty bomb or radiological dispersal device
Conventional explosives may be used as a “dirty bomb” by putting the isotope, such as 137Cs, within a conventional weapon, detonating it, and spreading radioactive particles. The purpose of the weapon is to contaminate the area with radioactive material, serving primarily as an area denial device against civilians.
Attempts of radiological terror using dirty bomb
November 1995. Group of Chechen separatists buried a 137Cs source wrapped in explosives at the Izmaylovsky Park in Moscow.
December 1998. Security service discovered a container filled with radioactive materials attached to an explosive mine. The bomb was hidden near a railway line ten miles east of the Chechen capital of Grozny.(Link)
According to Australian intelligence sources, the militant group in Syria and Iraq have seized enough radioactive material to effectively build a “dirty” nuclear bomb.
Most of radioactive isotopes that might be released at CBRN incidents (e.g., 241Am, 60Co, 238Pu, 90Sr, etc.) are metals able to form insoluble products at reactions with many chemical compounds and materials. Thus, the remediation technologies developed for decontamination of soils and water from heavy metals are also applicable for uptake of these isotopes. In contrast, caesium is an alkali metal and most of its properties (including high solubility of almost all salts) are similar to other alkali metals such as sodium and potassium. It makes uptake of 137Cs from contaminated sites very difficult.