The New York Times starts strong:
[E]xtensive testing conducted at the Oak Ridge National Laboratory in Tennessee over the last several months has concluded that the material did not originate in Pakistan or other suspect countries, and one official said that “with a certainty of 90 percent or better, this stuff’s from North Korea.”
The New York Times suggests the link to North Korea is based on elimination of other sources:
Federal analysts, [intelligence experts] said, tooksamples of the Libyan uranium and compared its isotope fingerprint with those of uranium samples from other countries and, by process of elimination, concluded that the uranium had come from North Korea.
[Another expert] said the analysts could examine the U-234 concentrations in the Libyan sample and compare it with samples from deposits from around the world. Since Western intelligence agencies have no known samples of North Korean uranium, he added, the analysis would proceed by the process of elimination.
The Washington Post has a totally different science story. According to The Post, DOE:
…examined containers obtained from Libya—which gave up its nuclear programs in a deal with the United States and Britain—and picked up signatures of plutonium produced at Yongbyon, where North Korea has its nuclear facilities. The U.S. official said that because North Korea probably would have produced much of the uranium hexafluoride at the Yongbyon facility, this was deemed the link that connected the material in the containers to the North Koreans.
The Times implies tests linked the material directly to North Korea, but the Post suggests the “smoking gun” concerns the containers of UF6 (presumably like the US model pictured above) to Yongbyon—though trace amounts of a different fissile material.
Either way, Pyongyang has some explaining to do.
Paul is preparing to weigh in with a meatier analysis later this afternoon.
Whirledview has lots to say, down to the correct spelling of fluoride.
Note: Careful readers will notice that version 1.0 didn’t mention the New York Times’ scientific analysis. My bad.