Blog Post - Nuclear Security Matters

Replacing Radioactive Sources

  • Miles A Pomper
| Feb. 04, 2015

For years, security experts have believed that the most likely form of nuclear terrorism would involve the use of radioactive sources such as “dirty bombs’. Yet, spending by governments, including the U.S. government, to secure or destroy such materials has been paltry. Far higher priority (if still not sufficient) has been accorded to efforts to remove or secure nuclear weapons useable materials, such as highly enriched uranium.

On the one hand, such prioritization is understandable. After all, nuclear weapons could kill tens, or hundreds of thousands of people, while radiological source fatalities might be in the single or double digits. And the expense and difficulty of increasing security for the enormous number of radioactive sources at thousands of civilian facilities around the world—from hospitals to oil wells and industrial sites—is significant.

Nonetheless, the economic, political, and psychological effect of a successful radiological terrorist attack would eclipse any security costs—paralyzing a major city because of the contamination of key areas and deeply wounding the global economy. It therefore make sense to take steps to reduce or eliminate this risk;  yet  at current spending rates the problem will not be seriously tackled for decades.

One approach which might resolve this dilemma is to find substitute non-radioactive materials that can serve many of the same useful civil purposes currently carried out with radioactive sources. Support for such an approach has been growing both in the United States and abroad.

Seven years ago, at the behest of Congress, the U.S. National Academy of Sciences (NAS) published a landmark report Radiation Source Use and Replacement. That study examined the feasibility of replacing high-risk radioactive sources with less risky (and most likely non-isotopic) alternatives in order to forestall an act of radiological terrorism.

Since then, a quiet behind-the-scenes battle has been waged both in the United States and overseas over how far such efforts should go. Some foreign governments, federal agencies, and U.S states have advocated for a more aggressive approach, concerned both by the threat and the short and long-term financial and practical difficulties of securing the thousands of such high-risk sources from theft or misuse. On the other hand, source manufacturers, and some U.S. government and international agencies have been more cautious, given the many positive benefits these sources provide in fields from medicine to oil and gas exploration and industry. 

Within the federal government, the ongoing locus of this fight has been the quadrennial report of the interagency Task Force on Radiation Source Protection and Security, which issued important reports in 2010 and 2014.[1] The 2010 report was a very cautious document, even expressing apprehension about how far to proceed with replacing what the NAS report has signaled out as the biggest risk—the continued use of cesium chloride (particularly in blood irradiators) whose unique characteristics make it especially susceptible to being used by terrorists.

By contrast, the 2014 report was much more aggressive in its approach to substitution and made a number of useful recommendations and has led to the formation of an interagency working group on the matter. At the same time, some members of Congress have been pushing for stronger action. Sen Dianne Feinstein (D-Calif.), then chair of the Senate Energy and Water Appropriations Subcommittee, pushed legislation through the appropriations panel endorsing a timetable for substituting out high-risk sources. After resistance from the House, however, these measures did not make it into the omnibus spending bill Congress passed last fall.

International support for replacing high-risk sources has also been growing. In its progress report to the 2014 Nuclear Security Summit (NSS), the United States says that it “intends to establish an international research effort on the feasibility of replacing high-activity radiological sources with non-isotopic replacement technologies, with the goal of producing a global alternative by 2016.” France, in its National Statement to the 2014 NSS calls for “minimizing the use of high activity sealed sources where it is technically and economically feasible,” citing its use of x-rays rather than cesium chloride in blood irradiators as an example. Other governments—from Norway to Japan—have taken similar steps when it comes to cesium chloride and are looking at other materials.

At the 2014 International Atomic Energy Agency (IAEA) General Conference, Energy Secretary Ernie Moniz announced that the United States had committed to work jointly with France, the Netherlands and Germany to establish a roadmap of action that would include support alternatives for radioactive sources.  They and other governments should bring a “gift basket” to the 2016 NSS in which they agree to take measures to substitute non-isotopic alternatives for high-risk sources in order to permanently reduce the threat of radiological terrorism.

[1] The task force is  headed by the Nuclear Regulatory Commission and includes 14 federal agencies and one State organization The 2010 and 2014 task force reports and additional information on the task force and their implementation are available at

For more information on this publication: Please contact the Belfer Communications Office
For Academic Citation: Pomper, Miles A.Replacing Radioactive Sources.” Nuclear Security Matters, February 4, 2015,

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