Tracking nuclear material worldwide.

• Position: Detection

It take just a Jew kilograms of plutonium, and less than 20 kilograms of highly enriched uranium to make a nuclear bomb. According to a database compiled by researchers at Stanford (Calif.) University's Institute for International Studies (IIS), about 40 kilograms of weapons-usable uranium and plutonium have been stolen from poorly protected nuclear facilities in the former Soviet Union during the last decade. While most of that material has been retrieved, two kilos of highly enriched uranium taken from a research reactor in Georgia is still missing, and that's just for starters.

"I think this is the tip of the iceberg," says Lyudmila Zaitseva, an IIS researcher who has been sifting through databases, technical journals, and newspapers since 1999 to compile what could be the most-complete picture of illicit trafficking of nuclear material worldwide. She estimates that the real amount of missing weapons-grade material could be 10 times higher than is officially known. For example, law enforcement officials in the U.S. seize just 10-40% of illegal drugs smuggled into the country every year, and Russia stops only two to 10% of immigrants and illegally imported goods entering from neighboring Kazakhstan. Based on such statistics, Zaitseva's estimate of missing nuclear material is not far-fetched. "We don't know what's missing," she notes. "That's the most frightening thing."

Nuclear physicist Friedrich Steinhausler is the driving force behind the IIS Database on Nuclear Smuggling, Theft and Orphan Radiation Sources (DSTO). Unlike existing databases, it aims to cover incidents worldwide because "the new terrorism is global," he warns. "Not knowing what goes on globally is like having [blinders] on."

DSTO combines information from two unclassified databases with additional open sources confirmed by government agencies. The Stanford researchers then reevaluate that material for accuracy. "You'd be surprised how much scientific junk is in the existing databases, from mixing up units to reporting on tertiary sources," Steinhausler indicates. "We decided to look at each case--is it scientifically credible? And who is reporting this? Is it a scientific agency or a central Asian local newspaper?"

The database, which will be accessible only to carefully vetted researchers cooperating with the IIS team, focuses on illicitly trafficked material and what is referred to as "orphaned" radiation sources--material that has been lost intentionally or by...