By Chris Healey
Radioisotopes can be used to construct radiological weapons. The United Nations reported 140 cases of missing or illegally-used radioisotopes in 2013. Each instance represents a potential threat to safety and security.
Radiological dispersal devices, or dirty bombs, are mundane. They do not deserve the mystique commonly associated with the term. Dirty bombs require little technical expertise to assemble and detonate. Radioisotopes, the defining component in dirty bombs, are abundant. A radioisotope is any unstable element that releases matter or energy. They can be found in common occupational tools such as well-logging and medical diagnostic equipment, and in household items such as smoke detectors.
Components required to create dirty bombs consist of conventional explosives, detonation apparatuses, and radioactive isotopes. Design simplicity makes dirty bombs accessible to those with little or no technical knowledge. In contrast, biological and chemical agents require expertise to create viable weapons. Complexity serves to complicate production processes, thereby limiting creation success rates.
Simple construction and abundant components make dirty bombs an attractive attack method. Surprisingly, they are rare. According to data from the Radiological and Nuclear Non-State Adversaries Database, dirty bombs, and other radiological weapons, have only been used 19 times by non-state actors.
Radiological and nuclear weapons are often conflated. Nuclear weapons employ physical processes of fusion or fission to release massive amounts of energy. Fission is the process of splitting an atom. That process yields smaller atoms, neutrons, and energy. Fusion is the process of combining two atoms to create one, yielding energy. Both processes require extraordinary and precise conditions for realization. Fusion and fission expel devastating amounts of energy, tantamount to the detonation of thousands to millions of tons of TNT. Furthermore, both fission and fusion require rare radioactive isotopes, profound scientific expertise, and expensive equipment. The cost and technical nature associated with fusion or fission make device creation insurmountably difficult. Conditions to create fusion and fission contrast sharply with dirty bomb detonation requirements.
Conventional explosives spread radioisotopes upon detonation. Radioisotopes retain radioactivity after blasts, contaminating surrounding areas with radiation. Conventional explosives are incapable of producing fusion and fission reactions. Nuclear weapons and dirty bombs share only the ability to spread radioactive material. However, destructive abilities of the two weapons cannot be compared; dirty bombs are exceedingly insignificant in comparison to nuclear weapons.
Other than the conventional explosive blast, inhalation of dispersed radioactive debris is the greatest health threat of dirty bombs. In almost all cases, radiation dispelled by dirty bombs will be stochastic instead of deterministic. Stochastic radiation damage does not immediately harm the individual, but may lead to carcinogenesis months to years later. In other words, the health effects of dirty bomb debris will manifest long after an attack. Deterministic damage, often associated with nuclear weapons, causes harm hours to weeks after radiation exposure. It is associated with deterioration of radiation-damaged organ tissue, not cancer.
Dirty bomb non-use cannot be explained. However, every effort must be made to improve radioisotope accountability. Restricting unauthorized radioisotope access will decrease radiological attack opportunities.