Detecting Nuclear Material in Transport
One of the few good things that’s coming out of the U.S. terrorism policy is some interesting scientific research. This paper discusses detecting nuclear material in transport.
The authors believe that fixed detectors—for example, at ports—simply won’t work. Terrorists are more likely to use highly enriched uranium (HEU), which is harder to detect, than plutonium. This difficulty of detection is more based on its natural rate of reactivity than on some technological hurdle. “The gamma rays and neutrons useful for detecting shielded HEU permit detection only at short distances (2-4 feet or less) and require that there be sufficient time to count a sufficient number of particles (several minutes to hours).”
The authors conclude that the only way to reliably detect shielded HEU is to build detectors into the transport vehicles. These detectors could take hours to record any radioactivity.