North Korea has dug a new 800 m-deep tunnel at its nuclear test site in Punggye-ri in the northeastern province of North Hamgyong, and experts believe it will be ready for another nuclear test once it reaches a depth of 1 km, a Seoul daily reported Monday.
“If they continue digging the tunnel in Punggye-ri at the current speed, they could likely conduct a third nuclear test anytime after early April,” a South Korean government source told the Chosun Ilbo.
The tunnel had reached a depth of about 500 m by December, the newspaper said, adding that South Korean and US intelligence agencies estimate progress based on satellite images of mounds of soil dug from the tunnel.
The North conducted two nuclear weapons tests in 2006 and 2009.
“India and Pakistan became nuclear weapons states after five and six nuclear tests,” said Cheon Seong-whun, a senior research fellow at the Korea Institute for National Unification. “The North is also going to need further tests.” The first two bombs in 2006 and 2009 used plutonium, but there is speculation that the next one could be uranium-based, according to the report.
The North is believed to have 30-50 kg of weapons-grade plutonium, and another test would deplete these reserves now a plutonium-producing reactor at Yongbyon, about 90 km north of Pyongyang, has been switched off. But the North stunned neighboring countries last November by showing an “ultra-modern” uranium enrichment facility to a visiting US nuclear expert.
The North could also be weighing other provocations. It recently finished building an intercontinental ballistic missile test site in Tongchang-ri on the country’s northwestern coast, and could test a long-range missile there once radar has been installed, the daily said.