South Korean and U.S. authorities have yet to detect radioactive debris in the vicinity of Punggye-ri, North Korea, that is consistent with the North’s May 25th nuclear test.

South Korean government sources said both Seoul’s radioactivity detectors and U.S. reconnaissance planes have been unable to detect traces of radioactive isotopes such as krypton and xenon, two gases emitted after nuclear testing or reprocessing.

Nuclear engineering professor Suh Kune Yull of Seoul National University said that the seismic wave patterns emitted by the underground blast on May 25th were greater than the first test in October 2006. Thus, he point out to a higher possibility of radioactive particles having been emitted after the test.

Suh said an actual scientific confirmation for the North's second nuclear test may not be possible because the radioactive gases are reliably detectable for seven to ten days after the test.