North Korea's Unstoppable Nuclear-Weapons Program

"The reality is that even without any more tests, North Korea could still produce enough material to build one hundred nuclear weapons..."

In the past month, a disagreement has broken out into the open between the United States and its ally, the Republic of Korea, over the seriousness of the threat posed by North Korea’s nuclear-weapons program. This dispute, centering on whether Pyongyang can mount nuclear weapons on ballistic missiles—the United States says yes, and South Korea says no—reflects first and foremost the two sides jockeying for position over whether Seoul should introduce an advanced U.S. missile-defense system known as Terminal High Altitude Area Defense (THAAD). While THAAD is intended to deal with the threat from Pyongyang, Beijing opposes its deployment, given concerns that the system is really aimed at its own missile forces. But the dispute also reflects a bigger problem—namely, South Korea’s unwillingness to come to grips with the reality that the nuclear-weapons threat from the North is poised for significant expansion.

That expansion will benefit from accomplishments achieved between 2009 and 2014, banner years for Pyongyang’s nuclear-weapons and ballistic-missile programs. Aside from the obvious manifestations—two tests of nuclear devices and three of long-range rockets—North Korea has conducted a host of other activities intended to lay the foundation for the future growth of its nuclear deterrent. For example, in 2011, Pyongyang unveiled a new modern plant able to produce highly enriched uranium that can be used to expand its nuclear-weapons stockpile. More recently, that plant has doubled in size, possibly meaning it can produce twice as much of this material. On the missile front, aside from modernizing its main launch facility to test larger rockets, the North is also gearing up to eventually deploy a road-mobile intercontinental ballistic missile able to reach the west coast of the United States.

What do these developments mean for North Korea’s nuclear future? We have been looking at this prospect at the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies and have concluded that the threat is going to grow, perhaps quite dramatically, by 2020. Of course, predicting the future of North Korea’s nuclear and missile programs is difficult, given inherent uncertainties in prognosticating about the most secret programs in an already secretive country. But there is also more evidence about these programs today than at any time in the past, in part because of the availability of commercial satellite and on-the-ground photography able to spot new developments, but also because as these programs move towards fielding operational weapons through visible activities, such as testing, it is easier to observe their progress.

Given these uncertainties, any prudent analysis has to construct different scenarios ranging from a “worst case” outcome for the North Koreans—little or no growth—to a “worst case” outcome for its neighbors and the international community—a great deal of growth—with a middle scenario that essentially reflects their current program and where it is heading. We did that working with David Albright, a well-known nuclear nonproliferation expert and head of the Institute for Science and International Studies, starting with a baseline of ten to sixteen nuclear weapons in Pyongyang’s stockpile, based on our understanding of how much fissile material the North had produced by the end of 2014. And the projections were not just for numbers of bombs, but also looked at Pyongyang’s ability to build smaller, lighter weapons (allowing the North to place them on top of missiles) with greater yields (that would cause more damage). (See Graph)


The outcome is sobering. Whichever scenario takes place, the North Korean nuclear threat will grow at an alarming rate, although just how alarming remains unclear. Even in a worst-case scenario for the North Koreans—they do not conduct any more nuclear tests, their ability to produce nuclear material for more bombs remains limited and their efforts to acquire foreign technology are unsuccessful—Pyongyang’s stockpile grows 100 percent, from ten to twenty weapons. In the worst-case scenario for the rest of us, North Korea steps up its yearly nuclear-test program, operates plants at full capacity to produce bomb-making material and is successful in acquiring foreign technology. The result is a stockpile numbering one hundred nuclear weapons by 2020, as well as significant progress in miniaturizing warheads to place on missiles and in increasing the explosive yields of those weapons. In the third, most likely “mid-range estimate”—based on Pyongyang continuing its infrequent nuclear tests, a more reasonable rate of fissile-material production and limited success in foreign cooperation—North Korea could still produce fifty nuclear weapons.