A Window Into Kim’s Nuclear Intentions? A Closer Look at North Korea’s Yongbyon Offer


Is North Korea serious about denuclearizing in exchange for a new peace architecture on the Korean Peninsula? Analysts are split on the matter. Many reject the possibility out of hand, insisting that the regime views nuclear weapons as essential to its identity and security for the indefinite future. Others point to North Korea’s security environment as the root cause of its perceived need for nuclear weapons, and suggest that if its hostile environment were to change, the regime might be less committed to remaining a nuclear weapons state.

These competing hypotheses about regime intent and self-image can neither be proven nor falsified by North Korea’s observable behavior to date. The steps it took in 2018 — collapsing nuclear test tunnels but continuing to deploy ballistic missiles — are equally consistent with a bluffing strategy or with the initial phases of earnest engagement. Since the prospect of ultimate denuclearization remains unclear, in 2019 U.S. diplomats should look for nuclear rollback steps that not only improve America’s security and alliances, but also offer new windows into the regime’s nuclear intentions for the future.

Verifiably dismantling the 5MWe reactor at Yongbyon, as Kim Jong Un suggested in the September 2018 Pyongyang Declaration with South Korea, would be exactly that kind of step. Unlike nuclear test tunnels that can easily be re-dug elsewhere, North Korea’s lone weapons reactor would be difficult to replace at a clandestine location. Irreversibly shutting it down could effectively cap the regime’s plutonium and tritium supplies thereby placing an expiration date on its ability to field miniaturized high-yield nuclear weapons in the future. If the regime is indeed committed to solidifying its nuclear weapons status, these limits on future capabilities would be hard for it to accept. The prospect of Yongbyon’s closure is therefore not only of intrinsic security value for the United States; it can also function as a “differentiator,” helping test different hypotheses about North Korean intent. Probing Kim’s seriousness about Yongbyon may allow U.S. diplomats to pursue a tangible step toward nuclear rollback in the short term while helping them judge whether additional steps may be possible down the road.

Consider the common hypothesis that nuclear weapons are central to the regime’s identity and vision of the future. In that case, North Korea would likely seek to normalize its status as a nuclear weapons state and deploy long-range nuclear missiles indefinitely. Such a nuclear-determined regime would prize the preservation of its lone weapons reactor — where it can reliably produce plutonium and tritium — at all costs. Since plutonium bombs require less metallic fuel than uranium bombs, they are easier to miniaturize and mount on long-range missiles. While closing Yongbyon would not remove North Korea’s ability to produce uranium bomb fuel clandestinely, miniaturization of uranium-based weapons would require boosting their efficiency with tritium to remove bulky components and reduce the amount of uranium required to achieve critical assembly. Both plutonium and tritium can only be produced in the requisite quantities in reactors or large accelerators, which are much more difficult to replace at a clandestine location than other types of nuclear facilities. Because tritium has a 12-year half-life, cutting off its supply would place a time horizon on North Korea’s current stockpile of boosting fuel.

Therefore, if the regime were indeed committed to remaining a nuclear weapons state with a long-range capability, dismantling its bomb-fuel reactor would directly contradict that long-term goal. In that case, Kim’s Yongbyon offer itself would likely be a bluff to maintain an illusion of diplomacy, and President Donald Trump would be wise to call it.

The U.S. commitment to its own long-term tritium production can help illustrate the stark technical choices faced by a committed nuclear weapons state. Because the United States envisions deploying nuclear weapons indefinitely, planning for continued tritium production at U.S. reactors extends decades into the future. Nuclear weapons planners even warn of a “looming crisis for U.S. tritium production,” and urge policymakers to proactively ensure the availability of U.S.-origin tritium in the coming decades. If North Korea is, like the United States, intent on maintaining deployable nuclear weapons, it will view the long-term preservation of its plutonium and tritium capabilities with similar urgency.

On the other hand, if North Korea views its nuclear program as a temporary security blanket and hopes to eventually trade it away in a peace process with South Korea and the United States, it would need to make a significant concession to demonstrate that intent early on in the diplomatic process. It would also, however, need to retain some residual nuclear capability for continued bargaining leverage to keep the diplomatic process alive until a peace architecture is irreversibly established. Allowing U.S. inspectors to verify the dismantlement of their plutonium and tritium sources while leaving a crude uranium capability temporarily intact might be a good way for the regime to split that difference. It could thus serve as a first step to initiate the twin processes of nuclear rollback and political change.

Some Western observers suggest that the real threat comes from North Korea’s clandestine enrichment capability. Its hidden centrifuge plants will indeed give the regime considerable bargaining leverage in any future engagements, and flushing them out will be one of the hardest long-term challenges if denuclearization proceeds. But not all nuclear assets are created equal; retaining a usable nuclear capability is not a binary question of having or not having the bomb, nor a quantitative one of how many bombs one can produce. If nuclear weapons are to fit into a long-term strategic plan for North Korea, they would need to be deployable in operation. To date, no committed nuclear weapons state has ever settled for a crude, symbolic nuclear device that can be made from uranium alone, because such devices are less useful for actual deployment. If the regime proves willing to take verifiable steps that make it more difficult to maintain its more advanced, operational bombs in the future, that would suggest that its long-term commitment to nuclear weapons might not be sacrosanct.

Other skeptics have argued that, because the 5MWe reactor at Yongbyon is aging, dismantling it would not be a serious step. But U.S. nuclear experts who have toured the facility understand that while producing nuclear materials requires major national investments, it doesn’t require cutting-edge technology. If diplomacy with North Korea fails to produce tangible nuclear rollback, we can expect the 5MWe reactor to continue producing bomb fuel well into the future.

Exploring Kim’s Yongbyon offer in 2019 is not without pitfalls, however, and further clarification is needed on several important issues. Are genuine dismantlement measures — such as pouring concrete into the core of the 5MWe reactor — truly on the table, or will the regime offer “disablement measures” that are easily reversible, as it did in the Six-Party Talks? Will North Korea try to retain its IRT2000 nuclear research reactor and experimental light water reactor — which could conceivably be retrofitted to produce small amounts of tritium — as part of a civilian nuclear program, or will those be dismantled as well? For an interim deal on Yongbyon to be valuable for the United States, it should call for irreversible dismantlement of North Korea’s entire plutonium complex and on-the-ground access for inspectors to safeguard any facilities that remain for civilian purposes. These prospects are implied, but not explicitly stated, in Kim’s offer, and diplomats should explore them.

To begin to deliver on its promise of a denuclearized Korean Peninsula, the Trump administration needs nuclear rollback steps from North Korea that are not just tangible but which also carry information about the regime’s long-term strategy. Irreversible dismantlement of the 5MWe reactor would provide both by placing time horizons on the most dangerous parts of the bomb program while making the other parts less useful in the future. It would also go further than any previous U.S. policy has in physically rolling back North Korea’s nuclear infrastructure. Therefore, an interim deal that stipulates the right steps at Yongbyon would be a big diplomatic win that distinguishes Trump’s nonproliferation efforts from those of previous administrations while also adding credibility to the process of nuclear rollback for future administrations to build on.

It remains to be seen what North Korea’s true preferences are, and whether it will ever agree to give up nuclear weapons in exchange for a different political future. The goal of U.S. policy should be to probe for an answer to that question while leaving its security and alliances better off even if the answer is “no.” An overly ambitious strategy that demands complete denuclearization in the remainder of Trump’s current term will likely fail at both of those goals and risks continued deadlock. But if the administration pursues Kim’s Yongbyon offer as a beginning step in the nuclear rollback process, the president could either bolster the credibility of the denuclearization process or improve America’s diplomatic position by calling North Korea’s bluff.


Christopher Lawrence is a physicist and a nuclear security scholar. He is currently a fellow at Harvard’s Kennedy School of Government, where he studies the history of US engagement with North Korea.

Image: Dan Scavino Jr.