Chinese scientists warn North Korea about disaster threat at nuclear test site

Chinese geologists have warned their North Korean counterparts of a potential catastrophic collapse of a North Korean underground nuclear test site on China’s doorstep.

Researchers from the Chinese Academy of Sciences’ Institute of Geology and Geophysics briefed a North Korean delegation in Beijing late last month on the threat of an implosion at the mountainous Punggye-ri nuclear facility, about 80km from China’s border.

A day after North Korea said it detonated a hydrogen bomb at the Punggye-ri facility on September 3, a senior Chinese nuclear scientist warned that future tests at the facility could blow the top off the mountain, causing a massive collapse. The scientist said radioactive waste could bleed from cracks or holes at the site and be blown across the border.

Two days after the briefing in Beijing, North Korean Foreign Minister Ri Yong-ho announced suddenly at the United Nations in New York that Pyongyang might consider detonating a “most powerful” hydrogen bomb over the Pacific Ocean.

That prospect was underscored on Wednesday by another senior North Korean diplomat, Ri Yong-pil, who told US news service CNN that the foreign minister’s words “should be taken literally”.

The briefing in Beijing on September 20 covered a range of issues but North Korea’s nuclear tests topped the concerns for the Chinese government, according to Zhai Mingguo, a senior Chinese geologist who helped organise the meeting.

“This is a big, sophisticated problem requiring multiple, systematic approaches. Our [meeting] is only a part of [the efforts],” he said.

The North Korea delegation was headed by Lee Doh-sik, director of the Geological Research Institute at the State Academy of Sciences.

“He is a top government geologist in North Korea, but he is not involved in the nuclear weapons programme,” said Professor Peng Peng, one of the Chinese geologists who met the delegation.

The atmosphere was reserved but friendly, according to several scientists who attended the meeting. They said they were not allowed to reveal the content of their discussions because it involved “diplomatic affairs”.

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The Chinese foreign ministry said on Thursday that it was not aware of the briefing.

Lee, the only one of the six North Korean team members identified, had visited China many times before the briefing.

During their 10 days in China, the delegation also visited copper mines in Hebei and Shanxi, and other ore bodies that could help North Korea with its own mineral surveys.

The Chinese geology institute has been closely monitoring the tests across the border and released what its scientists believe is the layout and depth of underground tunnels at the testing site.

The latest nuclear test was estimated to be between 100 and 200 TNT, more powerful than all the previous nuclear explosions combined. It was followed by numerous earthquakes and massive landslides at the test site, which many outside geologists say makes it highly unstable.

All five of North Korea’s previous nuclear tests had been under the same mountain, with the bombs transported along a horizontal tunnel to the middle of the mountain and then lowered down a vertical drop up to 2km deep.

Some Chinese scientists said the risk of an implosion at the site was greater than ever and China would be covered in radioactive fallout if such a failure were to happen.

A researcher studying the radioactive risk from the North Korean nuclear programme at Peking University said China could no longer tolerate another land-based explosion.

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“China cannot sit and wait until the site implodes. Our instruments can detect nuclear fallout when it arrives, but it will be too late by then. There will be public panic and anger at the government for not taking action,” the researcher said.

“Maybe the North Koreans themselves have realised that the site cannot take another blow. If they still want to do it, they have to do it somewhere else.”

If North Korea did follow through and set off a test at sea in the open atmosphere it could present a global threat.

Lan Xiaoqing, an associate researcher at the Centre for Monsoon System Research at the Institute of Atmospheric Physics in Beijing, said a powerful explosion, like the eruption of a volcano, could eject pollutants to the stratosphere.

“The fallout can spread to an entire hemisphere,” he said.