I have been interested to see if the North Koreans detonated a plutonium or uranium bomb and so far there is no evidence at least in the air samples taken of either:
South Korean scientists failed to detect critical radioactive gas from air samples collected over the East Sea that could have proven whether North Korea used an enriched uranium device for its third nuclear test.
Using helicopters, the Navy collected air samples for 12 hours after the underground nuclear weapons test Tuesday, with winds blowing from the north, to try to catch any radioactive leakage from the nuclear test site in Punggye-ri, the northeastern tip of North Korea.
They brought the samples to the Korea Institute of Nuclear Safety, a state-run institute, for analysis.
The smoking gun they were looking for was a radioactive material called xenon. The types and amounts of xenon isotopes can demonstrate whether the North tested a plutonium- fueled device, as for its first two tests, or a uranium-fueled device.
When the North conducted its second nuclear test in 2009, the South’s scientists failed to detect any leaked gases. [Joong Ang Ilbo]