South Korea now has irrefutable proof that North Korea did, in fact, conduct a nuclear test earlier this month.
Shortly after an earthquake rattled the region near the North’s Punggye-ri nuclear test facility, scientists in the South detected minute quantities of xenon-133, a radioactive isotope, in air samples. Wednesday, they confirmed the gas came from North Korea.
In a press conference, Nuclear Safety and Security Commission Executive Commissioner Choi Jong-bae said his organization’s land-based xenon detectors in the northeastern part of South Korea detected traces of xenon-133 on nine occasions. It’s offshore units detected traces of the isotope four times.
"It was difficult to find out how powerful the nuclear test was with the amount of xenon detected, but we can say the xenon was from North Korea."
He added the NSSC could not confirm what kind of nuclear test had been conducted. North Korea claims it tested a miniaturized two-stage hydrogen bomb that could be fitted upon its Hwasong-14 intercontinental ballistic missile.
Xenon, like oxygen, is a naturally occurring “noble gas” that is generally colorless, but is used in manufacturing lights. Xenon-133, nearly three times as heavy as the natural version, is frequently detected after North Korean nuclear tests.
The amounts detected by the NSCC will have no impact on South Korea's environment and population, Choi said.