hankyoreh

former director of the Los Alamos National Laboratory

By Park Hyun, Washington correspondent

A leading US nuclear expert said North Korea's recent nuclear test was "successful," producing roughly double the force of the blast recorded after its second test in 2009.

Siegfried Hecker, a professor at Stanford University, gave his opinion in an email interview published on his website, saying the test exhibited the typical characteristics of an underground nuclear explosion with seismic waves of 5.0 to 5.1 on the Richter scale. http://cisac.stanford.edu/news/hecker_takes_hard_look_at_north_koreas_nuclear_test_20130214/

According to Hecker, the 2009 test generated two to seven kilotons of force. This means that his estimate of the latest blast's force ranged between four to fourteen kilotons, up to twice as much as the six to seven estimated by the South Korean Ministry of National Defense.

While he noted that South Korea and China had failed to detect any radioactive particles after the test, Hecker also said there was a strong possibility that North Korea opted to detonate a highly enriched uranium (HEU) device in its latest test. As a reason for this, he noted that the country's foreign ministry talked about a "qualitative increase in the nuclear deterrent" when announcing the test last month. Because of its limited stores of plutonium, an HEU weapon would be the only way of achieving this.

Hecker also said the aim of the test was to develop the technology to miniaturize a nuclear weapon.

"This test may have given them the confidence to [make a sufficiently small and lightweight weapon] for one of their shorter-range missiles," he wrote.

However, he also said North Korea was "many years away" from threatening the American continent.

In the interview, Hecker said the test took North Korea "one more step closer to possessing a missile-deliverable nuclear weapon" and suggested it would "expand its arsenal by stepping up production of HEU."

With its increased confidence in the deterrent value of its arsenal, he added, North Korea may become more provocative and aggressive toward South Korea, the US, and Japan.

Hecker concluded that the biggest impact of the nuclear test was that it would "signal that the Kim Jong-un regime, like its predecessors, has chosen bombs over electricity."

Normalizing relations, signing a peace treaty, and achieving economic development would become "much more difficult, if not impossible, for at least the next five years," he added.

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