PONI Debates the Issues Blog

Nuclear Semantics

Hot off the heels of the 2016 Nuclear Security Summit, the international community is once again abuzz with plans to secure nuclear materials and thwart the efforts of terrorists to acquire these materials. Chief among these efforts is securing nuclear and radiological materials. Are these efforts the same, though? The answer is a resounding “No.” Those in the nonproliferation and nuclear security fields understand the radiological “disruption” versus nuclear “destruction” paradigm and are familiar with the ubiquity of radiological materials versus the relative rarity of fissile materials. For most, however, this distinction may not be as clear.

One need look no further than October 2015 when the media reported a thwarted smuggling attempt in Moldova. Smugglers tried to sell a cache of cesium-135, an isotope nowhere near as radioactive as cesium-137, to ISIS. Almost exclusively, outlets reported that “nuclear smugglers” or “nuclear smuggling” were selling “nuclear materials.” These headlines were not limited to the fringes, but came from major news outlets such as BBC, CNN, and the Huffington Post. To nuclear professionals, this indicated that these smugglers had uranium-235 or plutonium-239, both of which are among the IAEA-designated “nuclear materials.”. It was something of a relief to find out it was only cesium-135. This was a difference between a few dozen casualties and the contamination of a city block and the possibility of thousands of casualties and the destruction of a city center.

Some may see this as quibbling over semantics and that the point is largely the same – smugglers had been caught with destructive radioactive materials, so who cares whether we call it nuclear or radiological? The difference is a meaningful one, unfortunately. By indiscriminately referring to radiological material as nuclear, it conflates not just the proper naming conventions but the effects of the materials and the weapons they make up. The greatest threat posed by a radiological dispersal device, or dirty bomb, is that it will cause mass panic and chaos, even if damage and contamination are minimal. If we continue to refer to dirty bomb materials as “nuclear,” then if one ever goes off, the reports will conjure images of mushroom clouds and mass destruction, making the chaos and mass disruption much worse.

That leaves nuclear professionals with an important task: to make clear to the public the distinction between radiological and nuclear materials. By clarifying that these are different materials with different properties and effects, you can help mitigate the chaos and confusion that would ensue should a dirty bomb go off. The next time you hear someone refer to cesium as nuclear, correct them and do your part to help change the narrative around radiological weapons.


Evan Thompson is a research associate with Octant Associates where he supports the Defense Threat Reduction Agency's Cooperative Threat Reduction program. He has also supported the Department of State's Chemical Security Program through CRDF Global and worked in the Department of State’s Office of Export Control Cooperation. Prior to his work at State, Evan conducted research in export controls as a Security Leadership Fellow with the Center for International Trade and Security and later as a Leonard M. Rieser Fellow with the Bulletin of the Atomic Scientists. He graduated with a B.A. in international affairs from the University of Georgia and an M.A. in security studies from Georgetown University

The views expressed above are his own and do not necessarily reflect those of the Center for Strategic and International Studies, the Project on Nuclear Issues, the U.S. government or any of its agencies.

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The views expressed above are the author’s and do not necessarily reflect those of the Center for Strategic and International Studies or the Project on Nuclear Issues. The content of this web site does not constitute an endorsement by or opinion of the Department of Defense or any sponsor of the Project on Nuclear Issues.