G.M. Gaukler, C. Li, S.S. Chirayath, and Y. Ding,
"Detecting Nuclear Materials Smuggling: Performance Evaluation of Container Inspection Policies,"
32(3), 531-554 (2012).
In recent years, the United States, along with many other
countries, has significantly increased its detection and defense
mechanisms against terrorist attacks. A potential attack with a
nuclear weapon, using nuclear materials smuggled into the country,
has been identified as a particularly grave threat. The system for
detecting illicit nuclear materials that is currently in place at
U.S. ports of entry relies heavily on passive radiation detectors
and a risk-scoring approach using the Automated Targeting System
(ATS). In this article we analyze this existing inspection system
and demonstrate its performance for several smuggling scenarios. We
provide evidence that the current inspection system is inherently
incapable of reliably detecting sophisticated smuggling attempts
that use small quantities of well-shielded nuclear material. To
counter the weaknesses of the current ATS-based inspection system,
we propose two new inspection systems: the Hardness Control System
(HCS) and the Hybrid Inspection system (HYB). The HCS uses
radiography information to classify incoming containers based on
their cargo content into "hard" or "soft" containers, which then go
through different inspection treatment. The HYB combines the
radiography information with the intelligence information from the
ATS. We compare and contrast the relative performance of these two
new inspection systems with the existing ATS-based system. Our
studies indicate that the HCS and HYB policies outperform the
ATS-based policy for a wide range of realistic smuggling scenarios.
We also examine the impact of changes in adversary behavior on the
new inspection systems and find that they effectively preclude
strategic gaming behavior of the adversary.
Associated Project(s):SHIELD (Smuggled HEU Interdiction through Enhanced anaLysis and Detection): A Framework for Developing Novel Detection Systems Focused on Interdicting Shielded HEU