US trains nuclear detectives to trace 'loose' nukes

As nuclear safety concerns rise, the US government is building a stable of nuclear detectives – offering summer internships to those interested in radiochemistry nuclear forensics.

It was not Urskan Hanifi’s night.

He was stopped at a border checkpoint just after midnight, crossing from Romania into Bulgaria, when guards doing a routine inspection of his car turned up documents written in Russian – including one that described a shipment of uranium.

It was enough to make the guards suspicious. Popping the trunk, they found an air compressor inside, and upon closer inspection a tiny amount of highly enriched uranium, encased in a small glass vial, encased in wax, encased in a lead container.

Busted.

The uranium in this nuclear-age nesting doll wasn’t weapons-grade, but it was sufficiently enriched to suggest that the batch it came from could be turned into a crude atomic bomb.

But where did it come from? And who performed a serious enrichment job on it?

Those questions, still largely unanswered in the 1999 Hanifi event, exemplify the kind of puzzle that falls to scientists involved in the small but vital field of nuclear forensics. Call it “CSI Atomic.” Now, almost a decade after the 9/11 terrorist attacks, the US government wants to ensure its nuclear forensics proficiency – and an adequate stable of scientists who know their way around radioactive materials.

The Nuclear Forensic and Attribution Act, signed into law last month, aims to improve coordination among US agencies that probe cases of nuclear terrorism or nuclear smuggling. And it encourages tighter international cooperation in probing incidents beyond US soil.

But just as important, it is designed to attract a fresh crop of scientists to the field, in recognition of a looming shortage of such expertise as current scientists near retirement. Scholarships for undergrads, fellowships for PhD candidates, and research awards to professors teaching in relevant fields are the government’s incentives.

In return for the PhD fellowships, graduates must work two years at a national lab or at other federal agencies that help investigate nuclear terrorism or illegal trafficking.

Federal agencies already were beefing up their ability to trace radioactive materials to their sources – either samples intercepted during an investigation or, in the worst case, residue collected after a “dirty” bomb or nuclear device detonates. Still, the new law gives these efforts a more formal status, something that is “gratifying” to William Daitch, head of the Department of Homeland Security’s National Technical Nuclear Forensics Center (NTNFC) in Washington.

Politicians from former Vice President Dick Cheney to President Obama have recently identified nuclear terrorism as America’s most serious security threat. A key reason for their concern: a steady drumbeat of attempted or actual incidents of nuclear-materials trafficking.

Between 1993, when the United Nations International Atomic Energy Agency began gathering data on illegal trafficking in nuclear materials, and 2008, the agency received 336 confirmed reports of criminal activity involving nuclear material. The IAEA logged another 421 incidents of stolen or lost nuclear material worldwide. Since 1995, reported incidents have averaged 19 a year.

Moreover, the soil for nuclear mischief may be getting more fertile. Nuclear energy worldwide seems poised for expansion, and, in the West, worries abound about Iran’s nuclear program. The ongoing US-Russia effort to retire more nuclear warheads, if successful, may increase the risk that decommissioned nuclear material could be stolen if adequate safeguards are not in place.

At the same time, a shortage of nuclear forensics experts looms, experts say, citing unclassified reports on the field and a soon-to-be-released study from the National Academy of Sciences.

Indeed, these days just 60 researchers – mainly at the national labs – have experience in nuclear forensics, and none of them works full time on it, says Benn Tannenbaum of the Center for Science, Technology, and Security Policy of the American Association for the Advancement of Science (AAAS).

Why so few? Many people with the skills to conduct nuclear forensic investigations opt for higher-paying jobs in other sectors, such as nuclear medicine or nuclear power.

Then, too, the US government ended underground nuclear-weapons testing in 1992, reducing the demand for a corps of full-time scientists who analyze test results and devise technologies to increase the precision and speed of that analysis, says Mr. Daitch at NTNFC.

But there’s much work yet to do, says the AAAS’s Dr. Tannenbaum. “We’re still not at the limits of physics as far as how accurate our measurements can be or how fast [they] can be taken.”

To attract young scientists into radiochemistry and nuclear forensics, the Lawrence Livermore National Laboratory in Livermore, Calif., finds summer internships to be a promising avenue for piquing the interest of undergraduates, says Nancy Hutcheon, who administers the lab’s program, funded by the NTNFC. At least six students “are doing graduate-thesis work that in some way is involved with the nuclear forensics arena,” she says.

One is Greg Brennecka, an Arizona State University student working toward a PhD in isotope geochemistry – a field that studies the abundance of chemical elements and their isotopes, including radioactive isotopes. Mr. Brennecka has spent several summers interning with the lab’s nuclear forensic scientists. Once he finishes at ASU, he says, he may wind up at another university doing research. “But over the long term, I would like to something like Livermore’s nuclear forensics program.”

One of his projects there: developing ways to help pinpoint which of the 150 uranium mines that ever existed on the planet a sample came from.

On TV, forensic scientists of every ilk produce results in no time, but the reality is slower – and Daitch acknowledges the potential for enormous pressure for quick results. Nuclear forensic scientists are working toward that end, but the Hanifi case illustrates the difficulties.

Nine months after Bulgaria confiscated the vial of uranium, the US requested the sample. It took another nine months for Lawrence Livermore scientists to finish their analysis. Physical traits of the sample indicate it came from outside the US. Traces of paper pointed to Europe as the source for the trees. The glass vial appeared to be similar to those used at nuclear-fuel reprocessing plants to archive samples.

As for Hanifi? He served a short prison sentence in Bulgaria and was fined the equivalent of $900. Soon after his release, Hanifi went home to Moldova and reportedly died a short time later under mysterious circumstances.

Patrick Grant, with the lab’s Forensics Science Center, says the material’s source remains uncertain, although some reports suggest that the uranium came from a nuclear-fuel reprocessing facility in Russia. In effect, it is a nuclear “cold case.”

Still, there are promising approaches to speeding an investigation.

One is to use high-speed supercomputers to model potential terrorist nuclear devices. The intent is to build a virtual archive of devices against which investigators can compare what they may one day find in the field.

Another is to use lasers to speed the analysis of a sample. Typically, samples must be first dissolved in a fluid, which can take hours, explains Michael Carter, who heads counterterrorism research at Lawrence Livermore. Laser preparation may make samples available for analysis much faster.