South Korea searching for radioactive evidence from DPRK nuke test
The South Korean Nuclear Safety and Security Commission said that eight samples have been sent for analysis, but that nothing was found in any of them. Finding certain types of isotopes, particularly xenon gas, would help experts determine whether a uranium or plutonium device were used, according to BBC.
Experts, however, said that if the blast was well-controlled and well-contained they may not ever find radioactive isotopes. South Korean planes and ships, as well as a Japanese plane, were sent out immediately to find samples. Xenon isotopes were detected after a 2006 North Korean nuclear test, but not after one in 2009.
The commission also said that no changes have been recorded at the country's 122 unmanned radiation monitoring stations. Experts said that it could be just a matter of luck to detect xenon because it decays so rapidly, BBC reports.
North Korea claims to have carried out the test underground using a miniaturized but powerful device. The resulting explosion sent out seismic activity that was detected by several nations. North Korea's first two tests were conducted using plutonium, but the nation is also believed to have a uranium-enrichment program.