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North Korea’s “Thermonuclear” Test: The Paradox of Small, developing Nuclear Forces By Anthony H. Cordesman

nkoreahead06 Jan 15. The reports on North Korea’s latest nuclear test are now more an exercise in uncertainty than a clear demonstration of North Korea’s actual nuclear capabilities. North Korea may or may not have been able to demonstrate its ability to use a fission weapon to produce some form of fusion or thermonuclear yield. It is still equally possible that it has simply lied, tried some form of fission-fusion design and failed, or has some uncertain degree of success in “boosting” a fission weapon and claimed this made it a thermonuclear weapon.

It is also important to understand that North Korea’s success in developing any given nuclear weapon will interact with its missile design reliability, and capability. This, in turn, presents the paradox that small nuclear forces with limited effectiveness can push a given power – particularly one with extreme authoritarian leadership – into nuclear postures that present far more risks than the far larger and more capable nuclear forces of major powers.

Thermonuclear Options: Single Stage

In the worst case, going from its past fission to a real thermonuclear design, the difference could be dramatic. It is possible, however, that North Korea has tested a crude single stage nuclear weapon more to celebrate its erratic leader than achieve major military effects, and it might well be difficult to determine its success in doing so. There are obvious risks in any public discussion of nuclear weapons design, but there are highly public sources that do seem accurate enough to illustrate the issues involved…

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Anthony H. Cordesman holds the Arleigh A. Burke Chair in Strategy at the Center for Strategic and International Studies (CSIS) in Washington, D.C.

Commentary is produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).

© 2015 by the Center for Strategic and International Studies. All rights reserved.


The Center for Strategic and International Studies (CSIS) is a bipartisan, non-profit organization founded in 1962 and headquartered in Washington, D.C. It seeks to advance global security and prosperity by providing strategic insights and policy solutions to decision makers.

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