Defying international warnings, North Korea conducted its sixth and most powerful nuclear test Sunday, claiming it was a hydrogen bomb that can be loaded onto a long-range missile.
In a statement, the Nuclear Safety and Security Commission said it has not found any traces of radionuclides, such as xenon, in its tests of soil, water and air samples following North Korea's sixth nuclear test.
It said air-sampling equipment installed on planes, ships and land radiation detection stations have been collecting samples to find traces of radioactive materials.
The commission said South Korea's background radiation currently remains at the usual level of 50-300 nanosieverts per hour, apparently unaffected by the North's nuclear test. (Yonhap)