Japan's Nuclear Regulation Authority (NRA), said it has not detected changes in air radiation levels within its territory, following North Korea's claimed test of a hydrogen bomb on Wednesday Jan. 6.
The Nuclear Regulation Authority disclosed Thursday it did not find either iodine or cesium in the airborne dust samples taken Wednesday afternoon from a height of 3 to 10 km by three Japanese air force planes which flew over the archipelago, news agency Kyodo News reported.
The test to calculate remains of radioactive materials in Japan was carried out after North Korea announced on its state TV it had conducted its first hydrogen bomb nuclear test - an extreme, which experts have been unable to confirm so far.
Finding radioactive material traces in the air would unearth information on the nature of the test of a H-bomb.
However, reconnaissance aircrafts deployed after North Korea's last atomic test in 2013 did not uncover such traces, which could mean the communist country managed to perfectly seal the tunnels where the detonation is said to have taken place.
However, the Nuclear Regulation Authority announced that 300 monitoring posts located inside Japanese territory did not detect irregularities in radiation levels between Tuesday afternoon and early Thursday local time.
The samples were collected by T-4 trainer planes of the Misawa, Hyakuri and Tsuiki airbases located in the districts of Aomori (north), Ibaraki (central), and Fukuoka (south) respectively.
Pyongyang's announcement on the nuclear test, the fourth in its history, has triggered international condemnation, and led the United Nations Security Council on Wednesday to take significant measures.