The nuclear test carried out by North Korea on 6 January is unlikely to have been of the powerful hydrogen bomb it claims. Nevertheless, the blast increases North Korea’s confidence that it has a useable device


By Mark Fitzpatrick, Executive Director, IISS–Americas

North Korea’s 6 January nuclear test breaks international law and norms, heightens the security challenges in the region and must be met with a firm response. But the world should not further empower the Kim regime by swallowing its bombastic claims. The test probably was not of a hydrogen bomb, at least not a successful one. It does not give North Korea a greater ability to target the United States.

H-bombs, which rely on fusion and a two-stage explosion, are up to a thousand times more powerful than a normal fission bomb. They are also described as thermonuclear. Yet the magnitude of the 6 January test, initially estimated to be about 6-7 kilotonnes, was on par with North Korea’s three previous tests. If the test releases emissions that can be picked up via monitoring stations and air sampling, we will learn about the composition of the device, but the North has been good at hindering venting from previous tests. The radioactive isotopes collected in Japan two months after the 2013 test were too old to even tell if plutonium was used.

It would also be unusual for a nascent nuclear state to so quickly be able to achieve the technological prowess to successfully assemble a two-stage device. Joe Cirincione, president of the Ploughshares Fund, suggests that North Korea may be basing its claim on using tritium, a hydrogen isotope, as a booster in a normal fission bomb – a far cry from an H-bomb. David Albright, head of the Institute for Science and International Security, posits other possibilities for a one-stage thermonuclear device.

Claims of an H-bomb test ‘in the most perfect manner to be specially recorded in history’, according to North Korean state media, are in keeping, however, with the regime’s bombastic character. The regime claimed the February 2013 test was of a miniaturised device with a much greater yield than previous tests, although the 4-8kt estimated yield was not significantly greater than the 4kt yield of the May 2009 test.

Whatever its composition, the 6 January test increases North Korea’s confidence that it has a useable nuclear device. For North Korea’s military purposes, making the bomb small enough to fit on its Nodong ballistic missiles, a proven system that can reach Japan and all of South Korea, and robust enough to survive atmospheric re-entry, is more important than developing advanced thermonuclear devices. For propaganda purposes, however, it makes sense to exaggerate capabilities. The thinking is that Kim Jong-un thereby looks more powerful to his people and more worthy of respect by other countries. 

While the North Korean public may be proud, respect will not be the global inclination. The universal response is rather one of condemnation. The United Nations Security Council, meeting in emergency session, will surely adopt new sanctions. China, which says it was not informed in advance, is angry enough to allow more penalties, albeit nothing that would threaten North Korean stability, which is Beijing’s first priority.

Nevertheless, the US and its allies can be expected separately to apply the kind of financial sanctions that were seen to be effective in persuading Iran to accept limits on its nuclear programme. Given North Korea’s greater isolation to begin with, such measures may have less impact. But as in the 2005 Banco Delta Asia case, restricting even a small amount of the leader’s slush fund can get Pyongyang’s attention. Such sanctions might then set the stage for negotiations.

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