The United States, as well as several other countries, expends considerable resources to protect stored special nuclear materials (SNMs), as well as to detect such materials if stolen or transported internationally. Especially if enclosed in high Z shielded containers, Pu, U and other transuranic materials are extremely difficult to detect in the normal flow of commerce. Radiation monitors are deployed at great expense at land border crossings and points of air and sea embarkation and debarkation in attempts to detect smuggled materials. Although effective for some contraband radioisotopes, these monitors tend to be relatively ineffective as a detection approach for small quantities of SNMs. New approaches continue to be worked on that promise to improve the detectability of these materials. More specifically, new means of probing specific signatures of nuclear materials are being developed that could enhance the detection probability of such materials while reducing the number of false alarms. For example, photon beams that excite specific states in the materials of interest promise to enable the detection and quantification of materials even for standoff distances with minimum impact on the environment. As a passive technology, muon tomography has offered real promise. But can such systems be developed and built with sufficient sensitivity and with a footprint feasible for realistic operations at isolated borders or in mainstream commerce?
The locations of the vast majority of stored SNMs are known and are in reasonably secure locations in several parts of the world. Assume that international agreements could be successfully negotiated that require cre-
ative, new configurations for storing SNMs. What innovative approaches could be developed and deployed that would make these materials more easily monitored and more detectable if stolen (e.g., tagged with coatings of detectable isotopes or with detectable gases that would be emitted if containers are breached?). What approaches could make these materials more easily traceable and less useable if they fell into the wrong hands?
SNMs are most likely to be with us for the foreseeable future. There are several international institutions and agreements that are in place to help manage the risk. Arguably these have been successful in preventing wider proliferation of nuclear materials as well as accidental or intentional nuclear events. But it is not clear how long this situation with continue.
• What are the scientific and practical limits of the detectability of SNMs?
• What new technologies to detect SNMs are under investigation and can they be practically developed and deployed nationally and internationally?
• In addition to technical performance and cost, what other criteria (e.g., radiation dose to operators, existing international agreements, host state motivations) must be considered in selecting detection technologies for deployment?
• What are the institutional barriers to international “requirements” that SNMs be more detectable and/or less usable?
• Since SNMs are likely to be with us for a long and unpredictable length of time, what are suggested improvements to international institutions to manage the risk?
• Given the grave consequence of a failure to manage the risk, are efforts in training specialists adequate?
IAEA safeguards agreements and additional protocols: non-proliferation of nuclear weapons and nuclear security. International Atomic Energy Agency, April 2005.
IAEA safeguards agreements and additional protocols: verifying compliance with nuclear non-proliferation undertakings. International Atomic Energy Agency, September 2011.
NNSA next generation safeguards initiative fact sheet. U.S. Department of Energy, National Nuclear Security Administration, Jan. 2, 2009.
Nuclear energy research and development roadmap: report to Congress. U.S. Department of Energy, April 2010.
IDR TEAM MEMBERS
• Brandon P. Behlendorf, University of Maryland, College Park
• Peter C. Burns, University of Notre Dame
• Jacinta C. Conrad, University of Houston
• Julia R. Greer, Caltech
• Jie Lian, Rensselaer Polytechnic Institute
• Jessica Morrison, Freelance Writer
• Shriram Ramanathan, Harvard University
• William C. Regli, Drexel University
• Kenan Unlu, Pennsylvania State University
IDR TEAM SUMMARY—GROUP 3
Jessica Morrison, NAKFI Science Writing Scholar Freelance Writer, Washington, DC
IDR Team 3 considered innovative approaches that would make special nuclear materials (SNMs) more easily monitored and more detectable if stolen. After identifying problems and potential areas for technological development and implementation, IDR Team 3 established grand challenge areas (materials, technology, and systems) and self-selected into expertise groups to strategize ways to gather background information and develop potential solutions. Defining the grand challenge also included identifying problems with the current SNM monitoring and state-of-the-art detection.
What Are Special Nuclear Materials (SNMs)?
Since the end of the Cold War and the break-up of the Soviet Union in the early 1990s, the control of nuclear materials has been a strategic and costly necessity for nuclear nations bound by the Non-Proliferation Treaty (NPT), to which the United States is a signatory. Among its challenges is a requirement that signatories maintain control of radioactive materials that may be used as explosive devices or used to create nuclear explosive devices.
Special nuclear materials, as defined by Title I of the Atomic Energy Act of 1954, are “plutonium, uranium-233, or uranium enriched in the isotopes uranium-233 or uranium-235.” These are materials formed in nuclear reactors or extracted from used nuclear fuel that can be recycled to
manufacture nuclear explosive devices with or without transmutation or further enrichment.
Problems with Current State of the Art
Although monitoring at border crossings and ports of entry exists for radioactive materials, the passive detection methods widely deployed in these locations often lack the sensitivity to detect small quantities of SNMs shielded by lead or even water. The sensors are fixed in place and may require detection times as long as 10 hours for shielded materials. The IDR Team recognized these and the following as problems with the current state of the art:
• Deployment of detection and monitoring techniques is not standard worldwide.
• Variations in worldwide background radiation mean SNMs could slip through undetected.
• High false alarm rates encourage security personnel to turn off detectors.
• Active interrogation by imaging or detection of high-energy gamma radiation is expensive, limited in availability, and may pose privacy and public health concerns.
• Current detection technology doesn’t provide enough information efficiently and there is no integration with other critical sources of information, like geospatial tracking devices.
• After SNMs are detected, there is no direct pathway for identifying a material and its source.
• The pathway from technology development to implementation is slow and cumbersome.
Detecting the 1 Percent: Challenge Area Priorities and Recommendations
IDR Team 3 identified three challenge areas—materials, technology, and systems—and self-selected into groups based on expertise to gather background information and propose solutions to challenges determined by the larger group. Two groups formed—materials/technology and systems—as members of the materials and technology groups chose to combine.
Ninety-nine percent of SNMs are located securely in known locations worldwide. The materials/technology group asked, “How do we protect, detect, and identify the 99 percent of SNMs that we know about?” The group focused on physical tagging and/or chemical modification of this majority group of SNMs to make them more easily detected in the case of loss or theft. Specific actions included increasing the opportunity for detection by modifying a material to produce a dynamic signal that is chemical, electrical, or thermal; using existing GPS or radar technology within packaging that emits an alarm and transmits identifying information when movement is detected; and considering additional tracking mechanisms to provide built-in redundancy.
The detection of illicitly trafficked SNMs, the 1 percent, currently relies on technologies at border crossing that cannot detect small quantities of highly shielded materials. The materials/technology group asked itself, “How do we protect, detect, and identify the 1 percent of SNMs that we don’t know about?” The group focused on increasing the sensitivity of detection, identifying transformational uses of current technologies, and tracking motion with lasers and infrared. Specific actions included moving away from detection via alpha and/or gamma particles or creating a detection method that would excite or amply these traditional signals; improving existing and developing new technologies to better detect shielded material using thermal and imaging methods; and integrating detection systems with cell phones using thin-film technology.
The systems group considered the role of game theory, institutional and sociocultural barriers, environmental solutions, the balance between security and detection, the insider threat, and the role of intelligence and deterrence as a way of modeling the adversarial threat. “Instead of trying to find the needle, remove the hay,” said one team member. The systems approach concerns the 1 percent of SNMs that are not securely stored.
Threat modeling of illicitly trafficked SNMs requires understanding a widely distributed and ever-changing adversary. Detection, too, should be imagined as a complex, adaptive system that is widely distributed. The systems group considered specific actions including moving away from fixed sensors and toward cheap, small, mobile, and widely distributed sen-
sors for detection; addressing false alarms by requiring multiple alarms for detection; developing new methods to analyze and refine the distributed network detection system; and creating a network of worldwide background radiation profiles. Further, adoption by states, agencies (taxi drivers, for example), and individuals (as nodes in the system) would enhance detection capabilities.
An integrated approach to protecting, detecting, and identifying SNMs that considers materials, technology, and systems is expected to create a more complete operational picture of material status and those adversaries who would attempt theft, transport, sale, or unauthorized use of SNMs.
Improving existing infrastructure by the addition of enhanced sensors, remote detection, specially designed shielding containers that respond to motion, and a networked systems approach would make better use of existing resources, enhance detection, and reduce costs. Although challenges exist in sensor design, information integration, technology adoption, and any number of unknowns (e.g., as yet unimagined countermeasures to detection), progress toward making the world safer against threats from the illicit use of SNMs may be enabled through improved effective use of existing technologies, the inclusion of a well-connected public in problem solving, and the development of new benchmarks for success.
SNMs will be with us for the foreseeable future. Prior and current initiatives to control and detect SNMs have been expensive and time-consuming while doing little to advance the technology needed to sufficiently secure nuclear materials. An integrated approach that considers innovations in materials, technology, and systems is central to the solutions recommended by IDR Team 3. If successful, such an approach would make better use of existing resources, enhance detection, and reduce costs. The benefit to society is great—a world free from nuclear threat at the hand of rogue actors.