DPRK History

Yongbyon Nuclear Complex

A Comprehensive History of North Korea’s Nuclear Program

Siegfried S. Hecker, Robert L. Carlin, and Elliot A. Serbin

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Pyeongyang Press Corps/Pool/Getty Images

2018 Update

The study of North Korea's nuclear program and the denuclearization framework have been updated to reflect developments in 2018.

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The evolution of North Korea's nuclear program

An extensive literature review, combined with analysis by Robert Carlin, Siegfried Hecker, and other subject-matter experts, provides a comprehensive picture of the evolution of North Korea's nuclear program.

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Understanding the relationship between political and technical developments

The analysis helps to illuminate how critical decisions affected the direction of the nuclear program. It points to numerous “hinge points” that proved critical in the evolution of the program and relations between North Korea and the United States.

Charting North Korea's Nuclear History

The color chart provides a visual interpretation of year-by-year diplomatic, technical, and political developments.

Three shades of red denote negative effects and three shades of green denote positive effects. A list of the coding criteria is available here.

A written narrative provides detailed explanations of the key developments on an annual basis, supplementing the color chart.

Access a PDF summary of the project (Updated: April 2019)

Key Takeaways

North Korea's Nuclear Progress
North Korea's pursuit of nuclear weapons has been deliberate, determined, and patient. The nuclear program is not the most secretive in the world and North Korea's progress has not come as a surprise.

US Diplomacy
US diplomacy since 2000 has been sporadic, reactive, and often motivated by a desire to avoid risk instead of manage risk. North Korea's nuclear program has been slowed, sometimes reversed, during periods of diplomacy but it has never been abandoned. One of the most important factors in slowing North Korea's nuclear program has been US/IAEA presence in Yongbyon.

The charts show that nuclearization was a massive enterprise, taking 25 years to go to dark red. Going to dark green (denuclearization) will take time. Moreover, what does denuclearization mean? Does it mean no weapons, no deployed weapons, no fissile materials, no missiles, no people, and no civilian nuclear program?

North Korean Cheating
The narrative that North Korea "has cheated on every agreement" is neither accurate nor useful. We need to better understand the history of North Korea's nuclear program so as to not repeat mistakes.

What Now?
As bad as it was in 2017, the situation could get worse. The US has missed several opportunities in the past by not managing the incremental risks. The US must approach any denuclearization talks with an awareness of this history and a desire to manage the incremental risks so as to prevent the situation from worsening.

A technically-informed, risk management roadmap to “denuclearization”

Our detailed study of the North’s nuclear program identifies the most important initial steps to take toward denuclearization to be: no nuclear tests, no intermediate or long-range missile tests, no more production of plutonium and highly enriched uranium, and no export of nuclear weapons, materials or technologies.

The next chart suggests specific steps that can be phased in over three time horizons. In the short term, North Korea will surely hedge its bets by retaining parts of the program. But the risks in the yellow areas are manageable and will help focusing on the most immediate and pressing risks shown in red. The phased approach will also provide an effective way to build trust and interdependence, which are required for a viable long-term solution – complete demilitarization of North Korea’s nuclear program.

Read our recommendations in more detail here.

Roadmap to North Korea's Denuclearization: Key Takeaways


Phased approach to denuclearization
A “halt, roll back and eliminate” phased approach that will stretch over a decade or so will be required to denuclearize North Korea because of the enormity of its nuclear weapon enterprise and the huge trust deficit between Washington and Pyongyang.

Libya denuclearization model is not feasible
It is unimaginable that Kim Jong-un will accept immediate, complete denuclearization, which some in Washington have suggested to include shipping his weapons out of the country—that is simply too dangerous. The phased approach may be acceptable to Kim Jong Un and allow the United States to reduce the greatest risks first and address the manageable risks over time.

Pyongyang is encouraged to front-end load concrete denuclearization actions
Washington is looking for concrete nuclear dismantlement steps instead of ones that are easily reversed, as some of the conciliatory steps have been in the past. North Korea’s recent demolition of its nuclear test site is a good step in that direction.

Washington is encouraged to recognize Pyongyang’s desire for civilian programs
Pyongyang likely deems retaining rights to a civilian nuclear program, such as the production of electricity and medical isotopes, and peaceful access to space as essential. Considering the advanced state of North Korea’s nuclear and missile development, we consider the incremental risks posed by the civilian endeavors manageable. 

Verification is best achieved by cooperative measures
Verification of denuclearization, particularly down to the last weapons and kilograms of plutonium, will be virtually impossible in a confrontational environment. We suggest that cooperative efforts to demilitarize the nuclear and missile programs be explored, together with North Korea, South Korea and U.S. cooperation for civilian nuclear and space programs. Such cooperation will, in the long term and in conjunction with IAEA monitoring and safeguards implementation, make adequate verification much more likely.

Détente between North and South Korea is the potential game changer
The recent efforts at reconciliation between North and South, including two inter-Korean summits, have dramatically tipped the political landscape away from confrontation toward cooperation. Washington must be poised to take advantage of this environment to implement a risk management approach to denuclearization that we believe stands the best chance of long term success. 


We acknowledge the late Stanford University Professor John Wilson Lewis for the motivation and inspiration for this study. We thank the John D. and Catherine T. MacArthur Foundation and the Carnegie Corporation of New York for their support and encouragement for this work. We also thank the following for comments and suggestions on the study, although any criticism of its contents should be directed solely at the authors: Chaim Braun, John Delury, Michael Elleman, Ruediger Frank, Katy Gabel, Nick Hansen, Frank Pabian, Allison Puccioni, Kathleen Stephens, and Kathi Zellweger.