Table of Contents

As China expands its nuclear forces—a process that the U.S. government expects to continue—a broad consensus within the U.S. national security community about the importance of engaging China in arms control has emerged. The administration of U.S. president Donald Trump unsuccessfully sought to engage China and Russia in negotiations toward a trilateral treaty.1 The Biden administration has indicated it will seek to engage China and Russia separately. However, in public at least, it has not yet made any specific proposals for bilateral U.S.-Chinese arms control measures but instead has called generally for the two states to pursue “practical measures to reduce the risks of destabilizing arms races.”2

Beijing, meanwhile, has consistently rebuffed the United States’ entreaties, suggesting—without committing—that it will join multilateral disarmament negotiations only after the United States has reduced its nuclear arsenal to close the “huge gap” with China.3 Beijing has various concerns about engaging in arms control, but an important one is likely that verification might undermine the survivability of China’s nuclear forces by revealing sensitive information about them—the location of individual weapons, in particular.4

The United States cannot force China to negotiate. The Trump administration succeeded in demonstrating this lack of leverage through its fruitless call for Moscow to “bring China to the negotiating table,” and its discussion of conducting a nuclear test to pressure Beijing (a step that would likely have ended up fueling arms racing).5 Instead, if Washington is to have any chance of engaging China in arms control, it will have to craft proposals that mitigate Chinese concerns about transparency, while also identifying suitably valuable American concessions that could form part of a mutually beneficial quid pro quo. (China should undertake such thinking too as a good-faith effort to comply with Article VI of the Nuclear Non-Proliferation Treaty; as a practical matter, however, since it is the United States that wants to engage China, it is going to be up to Washington to work out how to entice Beijing to the negotiating table.)

Against this background, limits on warheads or even missiles would be a nonstarter. The limiting of launchers and bombers (see chapter 8) would be more viable, though is still an ambitious, long-term goal. For the time being, the most promising, albeit still challenging, approach is to focus on fissile material—the separated plutonium and highly enriched uranium (HEU) needed to produce nuclear warheads.

If China seeks to build up its nuclear forces to the point where they rival the United States’ arsenal in size, it will have to manufacture more than 3,000 additional nuclear warheads. According to the U.S. Defense Intelligence Agency, however, even if China converted all its available fissile material into nuclear weapons, its arsenal would still comprise only several hundred warheads (perhaps double its current stockpile).6 As a result, U.S. concerns about a Chinese nuclear buildup could be addressed by seeking to prevent any new production of fissile material.

Solution Concept

China and the United States should jointly declare a cutoff in fissile material production and adopt transparency measures to enhance this cutoff’s credibility. Ideally, the cutoff would extend to all fissile material production. In the real world, a more plausible approach would be for China and the United States to agree not to produce any more fissile material for military purposes and to place all newly produced civil material under International Atomic Energy Agency (IAEA) safeguards.

The United States unilaterally ceased the production of fissile material for any purpose, civil or military, almost thirty years ago and has no plans to restart it (indeed, it could expand its arsenal dramatically without doing so). It also published comprehensive declarations of its plutonium and HEU stockpiles in the mid-1990s—though has provided only one update (to the HEU declaration) since.7

There are widespread reports that China has ceased the production of weapon-usable fissile material for military purposes.8 However, Beijing has never officially confirmed them—possibly because it wants to retain the option of producing more such material.

China has ambitious plans to develop a civil reprocessing program.9 Its only existing civil reprocessing facility, a pilot plant with a small throughput, is probably no longer operational—though there is uncertainty here because, starting in 2018, China ceased to submit updates on its civil plutonium stockpile to a voluntary IAEA transparency initiative known as INFCIRC/549 (the United States remains an active participant).10 China is currently constructing one “demonstration” reprocessing plant and appears to be starting work on a second.11 Over the longer term, it aims to develop one or more industrial-scale facilities.

There is now growing concern within the United States that plutonium separated in these plants may be diverted for use in China’s nuclear weapons program. This concern has been fueled by China’s ambitious nuclear modernization efforts and by its plans to develop so-called fast reactors that will (if they can be made to work) produce plutonium particularly suitable for use in nuclear warheads. Given China is unlikely to relinquish its reprocessing program, a commitment to allow the IAEA to safeguard all newly produced civil fissile material could be the basis for a compromise.

A Joint U.S.-Chinese Fissile Material Cutoff and Associated Transparency Arrangements

China and the United States should declare a joint politically binding cutoff in the production of weapon-usable fissile material for any purpose and commit to talks about mutual confidence building.

If China is unwilling to agree to a complete cutoff because it is still producing, or plans to produce, fissile material for civil purposes, it should agree to a cutoff in production for military purposes and to place all newly produced HEU and separated plutonium under IAEA safeguards.

After agreeing to a cutoff, China and the United States should exchange confidential declarations about their stockpiles of weapon-usable fissile material. Specifically, for each of the following categories, each state should make annual declarations of its total holdings of (1) separated plutonium (unless it contains more than 80 percent plutonium-238) and (2) uranium-235 contained in uranium enriched to more than 20 percent:

  • Military material—material (other than excess military material) that has been fabricated, or is reserved for potential future fabrication, into nuclear weapon components
  • Excess military material—former military material that a state has committed not to use for military purposes
  • Naval fuel—irradiated or unirradiated fuel for military naval reactors
  • Other military material—material used for other military purposes (such as fresh or irradiated fuel for military research reactors)
  • Civil material—material involved exclusively in civil nuclear activities

The fissile material declarations are a confidence-building measure intended to complement the cutoff by providing comprehensive and regularly updated information about each state’s fissile material stockpiles. They would build on the United States’ previous voluntary declarations and on the information about civil fissile material that the United States makes available through INFCIRC/549 and that China used to make available through that same mechanism.


After committing to a bilateral cutoff in the production of weapon-usable fissile material, China and the United States should discuss any compliance concerns, with the aim of developing ad hoc verification measures to alleviate those specific concerns.

Verifying a cutoff in plutonium production should be unproblematic. The United States surely already uses NTM to monitor the nonoperational status of China’s military plutonium-production program. Similarly, China must use NTM to verify that U.S. military plutonium-production reactors and reprocessing plants are being decommissioned.12

Verifying a cutoff in HEU production could be slightly more challenging. China and the United States operate civil enrichment facilities to produce low enriched uranium, primarily for nuclear power reactors.13 However, all these facilities are technically capable of producing HEU, and China’s Heping facility—in which HEU for nuclear weapons was produced—may currently produce HEU for research reactors.14 If so, under a cutoff, such production would have to cease or be placed under IAEA safeguards.

Confirming the nonproduction of HEU at enrichment facilities would require physical access, which, to be politically palatable, would have to be reciprocal. While inspections conducted by either the IAEA or national inspectors would be intrusive, there would be few technical difficulties.

To verify that HEU is not being produced in an operational enrichment plant that has never produced such material, swipe samples could be taken and analyzed to confirm the absence of HEU particles. If such a plant has produced HEU, it might be possible to check that production has ceased by determining the minimum age of HEU particles.15 Failing that, the enrichment level of product streams could be measured through online enrichment monitors or periodic sampling. Finally, if either state were concerned that the other had built a secret enrichment plant to produce HEU for military purposes, swipe samples could again be used to confirm the absence of HEU particles at the suspect facility (if needed, the host state could use extensive shrouding to protect unrelated classified information).

In contrast to verifying a cutoff, the comprehensive verification of stockpile declarations would be functionally impossible. One reason is that classification rules around weapon components would prevent inspectors from measuring their fissile material content. That said, each state could compare the other’s declarations to its own intelligence estimates and commit to discussing inconsistencies. In particular, the past production of fissile material would be a less sensitive subject than its subsequent use or current disposition. It might therefore be possible to address discrepancies over production by being transparent about the operational histories of relevant facilities and by potentially using nuclear archeology (which involves analyzing components in facilities and waste streams to estimate past production).


Technical feasibility. Verifying a cutoff should be relatively straightforward, even if potentially intrusive. By contrast, verifying stockpile declarations, at least in any comprehensive way, would be impossible. Ultimately, China and the United States would have to decide whether or not they were better off receiving additional information, even if they could not verify it.

Political feasibility. This proposal would benefit the United States more than China—at least if implemented by itself. The United States has far more fissile material for nuclear weapons than it has use for, even though production ceased almost three decades ago. China, by contrast, has a much smaller stockpile, and while Beijing may not be producing more fissile material for nuclear weapons right now, it probably wants to maintain the option to do so. Indeed, China is probably quite pleased that Pakistan has blocked negotiations over a multilateral fissile material cutoff treaty, even if Beijing pays lip service to the goal of concluding such an agreement.16 In some ways, a bilateral agreement with the United States may be more problematic for Beijing than a multilateral treaty because it would not cover all the other countries that affect China’s fissile material requirements (namely, India, Russia, and perhaps even Japan). Nonetheless, Beijing has three potential motivations to explore this proposal.

Beijing may be reluctant to abandon the option of producing more fissile material because it is concerned about the survivability of its nuclear forces and believes it may need to manufacture more nuclear warheads in the future.

First, in practice, the proposed measure would not be implemented by itself. Inevitably, it would have to be adopted as part of a mutually beneficial package that required the United States to make significant concessions. To facilitate negotiations over such a package, Beijing should start considering what it would ask of Washington. Meanwhile, U.S. and Chinese experts could explore the trade space informally.

Beijing may be reluctant to abandon the option of producing more fissile material because it is concerned about the survivability of its nuclear forces and believes it may need to manufacture more nuclear warheads in the future. Chinese concerns on this score are driven, in no small part, by U.S. ballistic missile defense programs. At least in theory, space-based missile defenses would provide the most plausible means for the United States to undermine China’s nuclear deterrent and are a source of acute concern for Chinese experts.17 So, at the same time that China and the United States agreed to a politically binding cutoff in fissile material production, they could also agree, on a politically binding basis again, not to test or deploy space-based missile defenses. Such an agreement would be a step toward a legally binding trilateral prohibition (see chapter 7).

Second, in private, some Chinese officials and experts question the accuracy of the United States’ fissile material declarations. This proposal would help China gain deeper insight into the U.S. stockpile.

Third, while fissile material is unquestionably a sensitive issue for Beijing, this proposal would presumably be more acceptable to China than many, if not all, of the alternatives—binding limits on nuclear forces, in particular. Such limits would reveal the exact size of China’s nuclear arsenal and the locations of its weapons, exacerbating Beijing’s concerns about their vulnerability. By contrast, stockpile declarations would reveal only an approximate maximum size of China’s nuclear arsenal and nothing about weapon locations. To be sure, Beijing does not need to choose any of the alternatives; it could simply continue not to engage. Yet Chinese leaders should ponder the advice of the scholar Tong Zhao, who has argued that arms control could enhance China’s interests by preventing dangerously destructive competition with the United States, by bolstering China’s image as a responsible power, and by reducing defense spending.18 If those leaders agree with this argument in principle, this proposal could be part of a practical way forward.


1 “Trump Calls for Arms Control With Russia and China in Putin Call,” Reuters, May 7, 2020,

2 Ned Price, “Department Press Briefing—July 1, 2021,” U.S. Department of State,

3 Ministry of Foreign Affairs of the People’s Republic of China, “Department of Arms Control and Disarmament Holds Briefing for International Arms Control and Disarmament Issues.”

4 Wu Riqiang, “How China Practices and Thinks About Nuclear Transparency” in Li Bin and Tong Zhao, eds., “Understanding Chinese Nuclear Thinking,” Carnegie Endowment for International Peace, October 28, 2016, especially 237–239,

5 “Special Presidential Envoy Marshall Billingslea on the Future of Nuclear Arms Control,” Hudson Institute, May 21, 2020, 3,; and John Hudson and Paul Sonne, “Trump Administration Discussed Conducting First U.S. Nuclear Test in Decades,” Washington Post, May 22, 2020,

6 U.S.-China Economic and Security Review Commission, “Hearing on a ‘World-Class’ Military: Assessing China’s Global Military Ambitions,” Washington, DC, June 20, 2019, 35,,%202019%20Hearing%20Transcript.pdf.

7 “Global Fissile Material Report 2010: Balancing the Books: Production and Stocks,” International Panel on Fissile Materials, 2010, note 109,

8 For example, Hui Zhang, “China’s Fissile Material Production and Stockpile,” Research Report No. 17, International Panel on Fissile Materials, 2017, China reportedly fuels its naval reactors with low enriched uranium. See Hui Zhang, “Chinese Naval Reactors,” IPFM Blog (blog), May 10, 2017,

9 Hui Zhang, “China Is Speeding Up Its Plutonium Recycling Programs,” Bulletin of the Atomic Scientists 76, no. 4 (2020): 210–216; and “China’s Nuclear Fuel Cycle,” World Nuclear Association, August 2021,

10 International Atomic Energy Agency, “Communication Received From Certain Member States Concerning Their Policies Regarding the Management of Plutonium,” March 16, 1998, last updated October 15, 2021,

11 Hui Zhang, “China Starts Construction of a Second 200 MT/Year Reprocessing Plant,” IPFM Blog (blog), March 21, 2021,

12 The H Canyon at the Savannah River Plant is probably capable of extracting small quantities of plutonium from spent fuel, but it has never been used for this purpose. See “H Area Nuclear Materials Disposition,” Savannah River Site,

13 “China’s Nuclear Fuel Cycle”; and “US Nuclear Fuel Cycle,” World Nuclear Association, May 2021, Parts of one Chinese facility are under IAEA safeguards. The U.S. enrichment facility was offered for, but is not under, safeguards.

14 Zhang, “China’s Fissile Material Production and Stockpile,” 12–13. Additionally, both China and the United States have shut down gaseous diffusion enrichment plants. NTM should be adequate for monitoring their status.

15 “Global Fissile Material Report 2008: Scope and Verification of a Fissile Material (Cutoff) Treaty,” International Panel on Fissile Materials, 2008, 48–49,

16 Bates Gill, “China and Nuclear Arms Control: Current Positions and Future Policies,” SIPRI Insights on Peace and Security, no. 2010/4, Stockholm International Peace Research Institute (SIPRI), April 2010, 8–9,

17 Zhao, “Narrowing the U.S.-China Gap on Missile Defense,” 33–34.

18 Tong Zhao, “Opportunities for Nuclear Arms Control Engagement With China,” Arms Control Today, January/February 2020,