The Proposed Fissile-Material Production Cutoff

Nuclear nonproliferation has long been a principal security objective of the United States and most other countries. The nuclear nonproliferation treaty (NPT), which took effect in 1970, sought to limit nuclear weapons to the countries that then possessed them (the United States, the Soviet Union, the United Kingdom, France, and China). It is widely believed that, since then, several other states (India, Israel, Pakistan, and North Korea) have acquired nuclear weapons. One objective of current nonproliferation policy is to cap and eventually reverse the nuclear-weapon programs in these undeclared nuclear-weapon states. Another is to prevent terrorist and other subnational groups from gaining access to nuclear weapons or to sensitive nuclear materials, i.e., plutonium or highly enriched uranium (HEU). Such materials are produced in military and some civilian nuclear programs.

To help achieve these objectives, President Clinton outlined in September 1993 a "framework for U.S. efforts to prevent the proliferation of weapons of mass destruction." This framework included a proposed multilateral convention prohibiting the production of plutonium or HEU unless it is for purposes other than nuclear-weapon production and then only if it is done under international safeguards. The United Nations General Assembly endorsed the proposal within three months subject to the important change that the convention be "nondiscriminatory," that is, that it apply to declared and undeclared nuclear-weapon states and nonnuclear-weapon states alike.

What will be the effect of such a convention on the future availability of plutonium and HEU? Can additional steps reduce the opportunities for nuclear-weapon proliferation? What might be done to gain the international community's acceptance of further steps? In the research reported here, we have attempted to answer these questions.

Availability of Sensitive Nuclear Materials

To assess the effects of the proposed convention, we began by analyzing the current and near-future global availability of plutonium and HEU. We evaluated available data to determine countries' stocks of and ability to produce HEU and weapon- and reactor-grade plutonium (all of which can be used in weapons) and divided these amounts by that necessary to make crude atomic bombs. We carried out this analysis for undeclared nuclear-weapon states (named above) and nonnuclear-weapon states that once had an interest in nuclear-weapon development and have the ability to resume a weapon program (Argentina, Brazil, and South Africa). We found that these seven countries combined can now or will soon be able to produce enough sensitive nuclear material to manufacture about 230 bombs per year. This is in addition to a combined accumulated stockpile large enough to support the manufacture of about 220 bombs. (Seventy percent of this stockpile is in India and Israel.)

Some insight into the potential availability of sensitive nuclear materials can be gained by considering the separated plutonium being generated in countries with large reprocessing plants (France, the United Kingdom, Russia, and Japan). This plutonium is intended to be used in the nuclear fuel cycle, which will involve transfers between holding points including transfers to other countries. It is from these transfers and holding points that nations or subnational groups might divert or seize some of the material. We estimate the amount of plutonium in the cycle at any given time to be equal to the amount that the system can produce in a year. Combined, these states process enough plutonium annually to make approximately 4,400 atomic bombs; this number will grow to 5,600 within a decade. Thus, the diversion or seizure of even a tiny fraction of this material would be enough to make several bombs.

Effects of the Proposed Convention

What effect would the proposed convention limiting HEU and plutonium production have? First, although the convention does not deal with existing military stockpiles, it would put plutonium and HEU produced in the future in non-NPT states such as India, Pakistan, and Israel under full-scope international safeguards. This would have some of the effect of the NPT in that implementation of safeguards would deter the diversion of this plutonium and HEU for weapon purposes, and abrogation of the convention would afford some warning that weapons were being manufactured using this material.

Second, the proposed convention would require that nuclear-weapon states stop producing plutonium and HEU for weapon purposes. China would be most affected by this requirement, because it is the only nuclear-weapon state that may still be producing weapon-related plutonium. The other nuclear-weapon states no longer produce plutonium for weapons, and none produces HEU for weapons. However, the convention will formally commit them not to produce plutonium or HEU for weapons in the future.

The convention would thus increase the moral, legal, and to some extent, practical constraints on the production of nuclear weapons by non-NPT states, and it could decrease plutonium production by nuclear-weapon states. However, the question of how much potential for bomb-making would remain is still to be addressed. Our analysis shows why the proposed convention is only one element in President Clinton's nonproliferation framework.

The convention would leave in place existing stocks of plutonium and HEU accumulated for weapon-related purposes. There is also a residual risk associated with further production and stockpile accumulation carried out for nonweapon purposes—activities that would be allowed under the new convention (with safeguards). Parties to the new treaty could clandestinely build facilities to convert stored plutonium, which would probably be in oxide form, into the metal form needed for bombs, while simultaneously constructing the nonnuclear components of the weapons. Their efforts might not be detected until the oxide was withdrawn from the storage site (in violation of safeguards). It might be only a matter of days or weeks from that event until nuclear weapons were completed. And, with large flows of civilian fuel-cycle plutonium remaining, the threat of theft, as described above, remains.

Possible Further Steps

Having established that there will be a residual availability of plutonium and HEU for weapon manufacture after the implementation of the proposed convention, we considered two further steps as a means to reduce that availability. First, current plutonium and HEU stockpiles (both safeguarded and unsafeguarded) might be reduced or transferred to secure custody, and, second, the production of these materials for any purpose might be abandoned or restricted to fewer locations.

Reducing stockpiles should reduce the number of bombs that could be made. This would be a valuable step but not by itself sufficient. Even if excess stocks are eliminated, substantial plutonium would still be present at any given time in the civilian fuel cycles of countries with reactors using plutonium. Also, any nonnuclear nation interested in building nuclear weapons could provide itself with a plutonium stockpile by establishing a plutonium-based civilian fuel cycle.

Elimination of plutonium production for any purpose, on the other hand, should have a very large effect on its availability for weapon manufacture. If stockpiles were also eliminated, nonnuclear-weapon states would have nothing to seize and convert to bombs and subnational groups would have nothing steal. Nations such as Japan, France, and the United Kingdom, which are trying to establish a plutonium-based civilian fuel cycle as a hedge against exhaustion of uranium supplies, would be against a complete production cutoff. Consequently, the U.S. government, understandably reluctant to cross its allies, has declined to propose such a cutoff. However, because the economics of and political support for the civilian use of plutonium have been steadily deteriorating, various measures might be implemented to allay plutonium producers' concerns:

• Press the logic that plutonium stock disposition and a total cutoff or severe restriction on plutonium production will be necessary for effective control.
• Point to the U.S. example—the abandonment of civilian uses of plutonium—and add other examples, e.g., Germany. Also point to regional opponents of such programs, e.g., North and South Korea, and China with respect to Japan's program and perhaps Israel with respect to its neighbors' programs.
• As the number of holdouts is reduced, press harder on the remaining plutonium advocates.
• Initiate international efforts to improve the alternatives to plutonium use, including fuel-efficiency improvements in existing and advanced once-through low-enriched or natural uranium-based nuclear reactors and to identify additional uranium resources.
• Suggest the stockpiling of natural and low-enriched uranium fuel as a more immediate and proliferation-resistant energy security measure than plutonium fuel cycles.
• Suggest a progression of increasingly restrictive steps, beginning, for example, with a ban on new construction of plutonium facilities.
• Take actions to minimize the losses suffered by organizations currently profiting from plutonium activities.
• Cut off the production of "civilian" weapon-usable material first and use existing stockpiles to support sensitive activities that require time to phase out.
• Suggest a renewable moratorium on plutonium production.

Conclusion

If the proposed convention is supplemented by stockpile reduction or elimination and by severe restriction or total cutoff of plutonium and HEU production for any purpose, the danger of proliferation will be greatly reduced. The measures listed above might be taken to mitigate any negative effects such additional steps would have on some countries and thus improve the negotiating environment for further action.

We recommend that the United States at a minimum not foreclose, significantly delay, or deemphasize the possibility of further action to substantially reduce the availability of plutonium and HEU. It is important that the world perceive a U.S. position along the following lines:

• No nation should assume that the proposed convention offers an entitlement to activities it does not prevent. Otherwise, it may be difficult in the future to convince countries to abandon civilian plutonium fuel programs if they have made additional large investments in such programs under the auspices of the new treaty. To prevent such an eventuality, everyone must understand the limits at the outset.
• Negotiations over the proposed convention will be the first step, to be followed by or, better, accompanied by negotiations over a broader plan to cut off plutonium production and over stockpile disposition. Concurrent negotiations are better than sequential ones, given the length of time involved.

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