Spies fail to trace N Korea’s nuclear test

WASHINGTON - Reuters

S Korean activists gather in a rally denouncing North Korea’s nuclear test. REUTERS photo

U.S. and allied spy agencies have found no traces of telltale nuclear-related particles from North Korea’s Feb. 12 nuclear test, leaving unresolved basic questions about the device’s design, according to officials in the United States, Europe and South Korea.

This lack of scientific evidence suggests that key questions may remain unanswered about the type of fissile material used in the test, which was detected by seismic sensors. It also leaves unaddressed questions about how far the North has advanced in its bomb design.After the test, the U.S. Air Force Technical Applications Center in Florida dispatched WC-135 “sniffer” airplanes to look for traces of gas residue that could offer clues to the device’s design, but those efforts apparently turned up empty, the officials said. An Air Force spokesperson confirmed that the planes were dispatched but said no results from the missions could be released. A U.S. intelligence official said analysis from the tests “was continuing.”

In the two earlier tests, North Korea is believed to have used plutonium as the fissile core of its test devices.

Absent the trace evidence that might have been collected by sniffer planes U.S. and allied officials said it would be very difficult for outsiders to determine whether the latest test involved a plutonium or uranium core. A European national security official said the North Koreans were becoming “very effective” at hiding evidence that would offer clues to its nuclear secrets.