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Following the Clues: The Role of Forensics in Preventing Nuclear Terrorism

Sidney Niemeyer and David K. Smith

Although the more than 50 incidents of trafficking in nuclear and radiological materials each year are worrisome, these cases also provide valuable insight to the movement of these materials worldwide. Conducting thorough investigations that utilize nuclear forensics techniques to determine the source of interdicted nuclear materials can help prevent additional trafficking and ultimately terrorist use of nuclear weapons.

After all, the most likely early warning of an adversary’s planned nuclear attack will be previous involvement in illicit transfer of nuclear materials. Until now, however, local authorities have viewed such incidents as narrow violations of domestic laws rather than as threats to national and international security.

If nuclear forensic investigations become the norm for interdicted nuclear materials, investigators could analyze nuclear materials, devices or associated material to identify the source and the route of transit and ultimately help to identify the traffickers.[1] In particular, a nuclear forensics investigation might help answer such questions as: Is there a leak in one of the known holdings of nuclear material? Where was legitimate control lost? How did the material come to be where we found it? Can we link this material to the perpetrators? Is this case connected to previous cases?

A case becomes more significant if it can be linked to other instances demonstrating a sustained effort to sell or obtain nuclear material. Even some incidents that appear to constitute a relatively low threat, for example, trafficking in low-enriched uranium, ought to be investigated because such commerce may portend more serious threats. For example, an adversary may be attempting “trial runs” to test the ability to transport nuclear material without detection. Experience from law enforcement indicates that the combined evidence from two related cases enhances the probability of solving them both.

Once the difficult task of detection and interdiction has been accomplished, nuclear forensics should be used to understand the history of the interdicted material. If the source of the leak can be identified, steps can be taken to close that leak. A scenario that calls for a particularly rapid nuclear forensics investigation is one in which the perpetrators are close to assembling and detonating more than one nuclear bomb. The attacks of September 11, 2001, taught us that if a group of terrorists possess sufficient material, they might well attack multiple targets. Nuclear forensics, applied in time, can be the key to thwarting such a coordinated, multipronged attack.

Indeed, the use of nuclear forensics in a pre-detonation scenario may prove more effective as a preventative measure and deterrent than the more acknowledged scenario of using such techniques in the aftermath of a nuclear attack.[2] Deterrence works only when an adversary perceives that the consequences of its actions will be met by a credible and exacting response. In the case of a nuclear detonation, the typical stated (or implied) response is commensurately severe. Yet, some have questioned the government’s willingness to launch a devastating counterattack against those perceived to be responsible, especially when the evidence against the adversary might be less than unequivocal. By contrast, when the episode involves intercepting nuclear materials at an earlier stage, the response against a supplier could be less draconian and thereby viewed as more credible. Earlier intervention allows decision-makers more time to craft a broader and more measured response.

The time is right to promote the deterrent function of nuclear forensics. Several international instruments are now in place to advance forensic capabilities internationally. UN Security Council Resolution 1540 obligates states to take steps to prevent the spread of weapons of mass destruction and supporting technologies. The United States and Russia have recently spearheaded the Global Initiative to Combat Nuclear Terrorism, which provides for cooperation between law enforcement agencies to address the problem of the spread of radiological materials. Several U.S.-led efforts, including the Nuclear Trafficking Response Group and the Nuclear Smuggling Outreach Initiative, identify nuclear forensics as an important vehicle to ensure the responsible international stewardship of nuclear materials.

Using these arrangements, several specific steps need to be taken to enhance the usefulness of nuclear forensics in preventing nuclear terrorism. First, the United States and other states that have declared countering nuclear terrorism as a priority should seek to establish a new international norm that places far greater importance on conducting nuclear forensic investigations for interdictions of illicit nuclear materials. In a majority of past incidents, the investigation was conducted in the context of local government laws, often from the customs perspective that places a premium on the monetary value of the interdicted material, i.e., if you cannot sell it for much, we do not care much. New policies are necessary that emphasize threats to international and national security. All governments must be committed to pursuing these illegal acts to the fullest extent possible. Doing so would surely greatly enhance the global ability to detect the early warning signs of nuclear terrorist activity.

Second, greatly expand international cooperation in both developing nuclear forensics as a newly emerging discipline and pursuing nuclear forensic investigations. Nuclear smuggling is an international problem; identified smuggling routes do not neatly coincide with state borders. An informal and unaffiliated group that assembles the world’s leading experts in nuclear forensics, the Nuclear Smuggling International Technical Working Group (ITWG), has been working toward just that end since 1995.[3] The ITWG continues to make progress, but it would benefit greatly from new policies that support a greater level of cooperation. These would include much more vigorously developing bilateral R&D projects in nuclear forensics data collection and interpretation; establishing relationships for working cases collaboratively; advancing best practices in pursuing nuclear forensics investigations to establish a global “knowledge base” system that would draw upon subject matter experts and associated information in a way that also protects national interests; and increasing the scope of participation in the ITWG by new member states and organizations affected by nuclear trafficking.

Third, governments should make greater investments in improving their nuclear forensics capability. The magnitude of the investment depends on the extent to which policymakers agree on the relative importance of nuclear forensics in a national strategy for counterterrorism and nonproliferation. We suggest that the current level of investment will only slowly mature U.S. capabilities in nuclear forensics. If we are to embrace an international objective of true nuclear accountability, the appropriate technologies must enable the United States and its partner governments to trace illicit nuclear materials back to their points of origin and unauthorized diversion as well as help identify those responsible for these acts.


Sidney Niemeyer is a physicist at Lawrence Livermore National Laboratory and currently serves as a scientific adviser to the newly formed National Technical Nuclear Forensics Center in the Department of Homeland Security. David K. Smith is a geochemist at Lawrence Livermore National Laboratory and also serves as a scientific advisor on international nuclear forensics to the U.S. Department of State and the National Technical Nuclear Forensics Center.


1. International Atomic Energy Agency, “Nuclear Forensics Support,” Nuclear Security Series, No. 2 (2006), p. 67.

2. See Graham Allison, “Deterring Kim Jong Il,” The Washington Post, October 27, 2006; Michael May et al., “Preparing for the Worst,” Nature, October 2006, pp. 907-908; William Dunlop and Harold Smith, “Who Did It? Using International Nuclear Forensics to Detect and Deter Nuclear Terrorism,” Arms Control Today, October 2006, pp. 6-10.

3. L. Koch et al., “Proceedings: European Safeguards Research and Development Association,” 1999, pp. 805-810.