The first of two articles on nuclear security.Tomorrow’s comment, by Graham Allison, deals with nuclear terrorism.

By Neil Numark

   Previous summits between Presidents Bill Clinton and Boris Yeltsin have produced a series of measures designed to guard the "loose nukes" removed from retired nuclear weapons.At this week's meeting, the two leaders should move beyond such safeguarding strategies and agree to a timetable for destroying these materials which are the heart of the two countries’ nuclear arsenals.
    The second Strategic Arms Reduction Treaty -- START II -- set a timetable to remove all but about 3,500 nuclear warheads per side from their delivery systems by 2003.Both sides are making progress towards this goal.But there is still no requirement to dismantle the tens of thousands of removed warheads (although both sides have begun to do so) or to eliminate their fissile contents.
    Without a doubt, the most urgent priority is to ensure that these materials are extremely well protected so that terrorists or rogue states cannot get hold of them.But weapons materials are too dangerous to be simply stored indefinitely.Furthermore, even the most leak-tight storage arrangements cannot prevent the United States or Russia from using warheads again in a new arms race.Either side could easily break out from commitments under START simply by putting intact warheads back into operation or by assembling new warheads from stored fissile components.
    By the same token, either side could break the commitment Clinton and Yeltsin reached at their last summit: ex-weapons materials in excess of national security requirements will not be used to make new weapons.
    What if one or both sides change their mind about how much is required for national security?Clinton has taken a further step in pledging not to reuse excess materials in weapons by unilaterally withdrawing roughly 20 percent of materials from the nuclear stockpile and promising never to use them again to build weapons.Yeltsin should match that gesture, but even such orders can be reversed, making rearmament too easy in a period of conflict.
    Weapons reductions under START are vital, and promises not to reuse the released materials are helpful.But we now need a joint commitment to eliminate irreversibly the core components of the bomb.Clinton and Yeltsin should sign a Strategic Materials Reduction Treaty -- SMART -- establishing a framework and timetable for the disposition of weapons materials.Under SMART, the United States and Russia should jointly declare that the majority of our existing inventories of weapons-grade plutonium is no longer needed for national security purposes, and should agree to reduce inventories from the current level of about 100 tons apiece to 10 tons each by the year 2025.
A similar goal should be set for highly-enriched uranium.Each side could comply with this ambitious deadline by any methods that ensured irreversibility -- methods producing an end product so undesirable for bomb use that it would be easier to just make bomb materials again from scratch.
    Whatever methods are selected to dispose of weapons materials, it will take some time to achieve these large reductions.Therefore, a relatively quick and inexpensive first step that SMART should include, buying us increased security immediately, would be to deform the masses of plutonium metal -- the "pits" -- such that they would have to be melted down and re-fabricated in order to reuse them in a weapon.
But this step is still no substitute for final disposition.Most of the needed technology for disposition already exists, and the United States and Russia should move faster to implement it.
    The United States and Russia need to approach the disposition of nuclear weapons materials as partners in peace. This will require not only an agreed-upontimetable for rapid, mutual reduction of weapons materials, but also a system for verifying each other's compliance, as well as technical cooperation to ensure safe processing and an irreversible outcome.
    Cooperation with other nations will be needed as well.The necessary funding must be assured, and all G-7 nations should be willing contributors.Furthermore, while most weapons materials should be disposed within the United States and Russia, the use of facilities in other G-7 countries or elsewhere would make more rapid reductions possible and should be considered, as long as stringent safeguards and security can be guaranteed.
    SMART would achieve disarmament consistent with U.S. and Russian obligations under the Non-Proliferation Treaty, obligations which we had better meet if we want to preach nuclear non-proliferation to would-be weapons states.This could add momentum toward the conclusion of two multilateral treaties that the United States and Russia already support: a comprehensive ban on nuclear testing and a ban on the production of fissile materials for nuclear weapons.Without a formal pledge to eliminate weapons materials by the nations with the largest arsenals, other countries will see us sitting on large inventories indefinitely, with the option of future military use.Could we then reasonably expect them to renounce any further development of their own nuclear potential?
    Even during the Cold War it was widely acknowledged in both the United States and Russia that our nuclear arsenals grew far larger than necessary.The difference today is that the tide has turned, from an aggressive and dangerous arms race to mutual recognition of the problem and cooperation in disarmament.We should take advantage of these better circumstances and finally make the commitment not only to remove bomb materials from delivery systems, but also to eliminate the vast majority of them once and for all.

Neil Numark heads a Washington, D.C. consulting group specializing in nuclear safety and security and environmental protection issues.He contributed this comment to The Moscow Times.