Ziplock

BRATISLAVA, Slovakia - The arrests of three men who allegedly tried to sell contraband uranium for $1 million show how a shadowy black market for nuclear components has survived despite tightened security at nuclear facilities worldwide, experts said Thursday.

Slovak police said the material, believed to have originated in the former Soviet Union, was highly dangerous and could have been used in a radiological "dirty bomb" or other terrorist weapon.

In 2006 alone, the U.N. nuclear watchdog registered 252 reported cases — a 385 percent increase since 2002.

Hoskins cautioned that the spike probably was due at least in part to better reporting and improved law enforcement efforts. Of the 252 cases, about 85 involved thefts or losses, and not all the material was suitable for use in a weapon, he told The Associated Press.

He said the uranium had been stashed in lead containers, and that investigators determined it contained 98.6 percent uranium-235. Uranium is considered weapons-grade if it contains at least 85 percent uranium-235.

But nuclear experts who were shown police photographs of radioactivity readings contended the material was probably not as dangerous as authorities believe.

They said the police confused a scientific reading of the material as dealing with its "concentration" of uranium-235, when in fact it was just a "confidence" level of the machine to give an accurate reading. They suggested it may even have been natural uranium — a common and non-lethal element.

"Uranium is not very radiotoxic," said David Albright, a former U.N. weapons inspector who is now president of the Institute for Science and International Security in Washington.

"The net effect of dispersing half a kilo (about a pound) of uranium — who cares? Each person would get so little it would have no effect," Albright said.

Alexander Glaser, a researcher at Princeton University's Program in Science and Global Security, said any discussion of dirty bombs in this case was "off topic."

"Even naturally occurring uranium would be more effective than this in making a dirty bomb," he said.

Vitaly Fedchenko, a researcher with the Stockholm International Peace Research Institute, said people should not get the idea that the world is awash in easily obtainable bomb components.

"The danger is definitely there. But there's no reason to panic," he said. "Most of the 'buyers' out there are law enforcement agents. And not all of the materials out there are weapons grade."

In 2006, Georgian agents working with CIA officials set up a sting that led to the arrest of a Russian citizen who tried to sell a small amount of weapons-grade uranium that he had in a plastic bag in his jacket pocket.

In 1997, seven men who officials said planned to smuggle 11 pounds of enriched uranium to Pakistan or China were arrested in Novosibirsk, Russia. That uranium reportedly had been stolen from a plant in the former Soviet republic of Kazakhstan.

-----In his pocket?!