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Understanding Radiological Threats

  • Understanding the Radiological Threat

    The existence of thousands of poorly secured commercial radioactive sources globally poses an ongoing challenge to international security. Radiological dispersal devices (RDDs), in which conventional explosives are used to spread radioactive materials, do not pose the same high expertise and materials barriers as nuclear weapons. The acquisition and use of RDDs by terrorists is therefore a high probability threat. While a radiological attack would be unlikely to cause large numbers of casualties, it could incite mass panic, damage economic commerce in affected areas, and require expensive radioactive decontamination procedures. Effective response procedures and public education campaigns have the potential to mitigate public reactions in the event of an attack. Additionally, the international community can work to prevent an attack by continuing to secure vulnerable radioactive sources globally.

  • Balancing Legitimate Commercial Uses with the Threat of “Loose” Radiological Materials

    Radioactive sources have hundreds of legitimate medical, scientific, industrial and agricultural uses. These include food sterilization, radiotherapy, radiography, oil exploration, and industrial irradiation. State-owned facilities produce the majority of commercial radiological sources, and over one million radioactive sources exist worldwide. However, only a fraction of these have high enough levels of activity (or number of radioactive decays occurring per unit time), to raise security concerns.[1] Keeping track of the thousands of radiological sources worldwide throughout their life cycle remains an ongoing challenge. Poorly planned chain of custody procedures and a lack of regulatory controls in many countries have led to the loss of control over thousands of radiological sources. Even with regulatory controls, high disposal costs and a lack of depositories have led some end-users to abandon radioactive sources at the end of their life-cycle (disused sources).  Abandoned or orphaned sources present both a safety risk and a potentially high security risk.

  • Effects of Ionizing Radiation on the Human Body

    Radioactive material consists of unstable atoms in the process of naturally decaying and releasing energy. This type of material is found everywhere, including in soil, in bananas, and in the human body. However, a large enough quantity of specific materials that release certain types of radiation could be combined and dispersed by someone with malicious intent to perpetrate a radiological attack. Many of the same radioactive sources used to benefit humanity in the medical and industrial fields could pose serious human health risks in the wrong hands. Some of the radioactive sources used in these fields, such as strontium-90, cobalt-60, cesium-137 and iridium-192, often emit high-energy beta particles or gammas (high-energy photons).[2] While human skin provides a natural shield against alpha particles, both beta particles and gamma rays can penetrate human skin and potentially cause cell damage. Most beta particles can be stopped by a layer of clothing, but much more extensive shielding, such as concrete or lead, is required to protect the human body from gamma rays. Although alpha particles are the easiest type of ionizing radiation to shield against, they can cause more extensive damage inside the human body (if, for example, ingested or inhaled), than do beta particles or gamma rays. The effects of ionizing radiation on the human body depend not only on the type of radiation, but also on the source’s strength, the distance of the source from the individual, the material and amount of shielding between the source and the individual, the energy per particle or photon, and characteristics of the affected individual including age and health.[3]

  • The Threat of Radiological Terrorism

    The threat of a radiological attack by a non-state actor or terrorist organization remains an ongoing concern. A potential attacker might acquire radioactive material by locating an orphaned source, stealing a source from a licensed user, or illicitly purchasing a source. The attacker would be looking for a source that was highly radioactive, portable, and easy to disperse.[4] There are several ways terrorists could maliciously spread illegally obtained radioactive materials. The possible use of conventional explosives to scatter radioactive material in a radiological dispersal device (RDD) has gained widespread media attention. An RDD or “dirty bomb” would require only minimal technological expertise.[5] The effectiveness of an RDD would depend on the type of radioactive material, the size of the particles and how easily they disperse, the amount of material and explosives, and weather conditions.[6] An RDD would be unlikely to cause many casualties, and most if not all casualties would be caused by the conventional explosives rather than the radioactive material itself.[7] It would be likely, however, to cause widespread public panic and significant economic losses. This is why RDDs are sometimes referred to as “weapons of mass disruption.” Terrorists could also carry out a radiological attack without using explosives. Radiation emission devices (REDs) emit high-levels of radioactivity from a stationary radioactive source. Terrorists might also attempt to contaminate the food or water supply with alpha emitters, such as Polonium-210, though this technique has only so far been used in targeted assassinations. In November 2006, Po-210 was used to murder former KGB agent Alexander Litvinenko, who died three weeks after ingesting a fatal dose of the radioisotope.[8]

  • How is the International Community Working to Decrease the Radiological Threat?

    Many countries have taken measures individually and collectively to decrease the threat of radiological terrorism by securing commercial radiological sources. One of the most well-known initiatives in this area is the U.S.-led Global Threat Reduction Initiative, which has completed physical protection upgrades at over 960 radiological sites globally since 2004.[9] Other important preventative programs, for example the Second Line of Defense Program implemented by the U.S. National Nuclear Security Administration, include measures such as regulatory controls on radiological source transfers and radiation detectors at borders. Notable multilateral efforts include United Nations Security Council Resolution 1540 and the Nuclear Terrorism Convention. Also, the IAEA has established a Code of Conduct on the Safety and Security of Radioactive Sources. Over the long-term, the development and implementation of a “secure life cycle for radiological materials” would help minimize the risks of legitimate commercial applications.[10]

  • Reducing the Consequences of a Radiological Incident Through Public Preparedness

    Past radiological incidents have demonstrated that mass panic in response to an isolated radiological incident can cause serious disruptions to the social order and have lasting economic consequences. History suggests that public preparedness programs might help to minimize the consequences of any radiological incident—whether accidental or malicious. In Goiania, Brazil in 1987, looters stole a metal canister from a radiotherapy machine containing 1,375 curies of Cesium-137. The thieves opened the source and inadvertently spread the radioactive Cs-137 chloride powder within. More than two-hundred people were contaminated, while thousands more had to be monitored for radiation poisoning. Environmental clean-up operations alone cost approximately $20 million dollars. Hysteria led citizens to flee the area, crippling the tourism and agricultural industries. Had public education programs about radiological risks and well-planned emergency response procedures been in place, local authorities might have had greater success in managing the effects of the incident. The United States and other governments have worked to develop comprehensive response plans in the hopes of establishing organized capabilities to respond to radiological emergencies.[11]

  • Sources (Part 1)

    [1] “Inadequate Control of World’s Radioactive Sources,” IAEA Press Release, 24 June 2002, www.iaea.org.
    [2] Charles D. Ferguson, “Psychologically Immunizing the Public against Radiological Terrorism: Facts Can Free Their Minds,” in Social and Psychological Effects of Radiological Terrorism, eds. I. Khripunov et al. (Amsterdam: IOS Press, 2007), p. 11.
    [3] Jonathan Medalia, “Terrorist ‘Dirty Bombs’: A Brief Primer,” Congressional Research Service, Updated 1 April 2004, opencrs.com.
    [4] Charles D. Ferguson, Tahseen Kazi, and Judith Perera, Commercial Radioactive Sources: Surveying the Security Risks (Monterey, CA: Monterey Institute of International Studies, 2003), p. 14.
    [5] Chad Brown, “Transcendental Terrorism and Dirty Bombs: Radiological Weapons Threat Revisited,” Center for Strategy and Technology, February 2006.

  • Sources (Part 2)

    [6] Jonathan Medalia, “Terrorist ‘Dirty Bombs’: A Brief Primer,” Congressional Research Service, Updated 1 April 2004, opencrs.com.
    [7] Fred Burton, “Dirty Bombs: Weapons of Mass Disruption,” Stratfor, 5 October 2006.
    [8] Robin B. McFee and Jerrold B. Leikin, “Death by Polonium-210,” Response Guide for Chemical and Radiological Threats, www.nacct.org, accessed 24 August 2011.
    [9] “GTRI: Reducing Nuclear Threats,” National Nuclear Security Administration, 1 February 2011, nnsa.energy.gov.
    [10] Leroy E. Leonard, “Responding to Radiological Threats,” in Nuclear Safeguards, Security, and Nonproliferation: Achieving Security with Technology and Policy, ed. James E. Doyle (Burlington, MA: Elsevier, 2008), p. 488.
    [11] Federal Emergency Management Agency, “United States Federal Radiological Emergency Response Plan,” Federal Register, 8 May 1996, pp. 20944-20970.

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