Japan detects xenon in air after N. Korea nuclear test
TOKYO (AFP) - Japanese planes detected a trace amount of xenon-133 during monitoring flights over Japan the day after North Korea carried out its third nuclear test last week, the science ministry said Thursday.
The radioactive material amounting to 1.9 millibecquerels per cubic metre of air was detected from samples collected at an altitude of 300 metres (990 feet) off the coast of Aichi prefecture in central Japan, Jiji Press reported.
It was the first time Japan had detected xenon-133 since it strengthened radiation monitoring in response to the test on February 12, the news agency said.
Xenon-133 is released into the air not just by an atomic explosion but also from nuclear power plants and medical institutions.