Effective approaches to the management of plutonium and highly-enricheduranium (HEU) are fundamental to controlling nuclear proliferation andproviding the basis for deep, transparent, and irreversible reductionsin nuclear weapons stockpiles. This article will focus on the UnitedStates and the former Soviet Union, where by far the largest stockpilesof nuclear weapons and weapons-usable nuclear materials are located.

The United States and the nations of the former Soviet Union have begun abroad program of cooperation designed to:

1. reduce the risk that nuclear weapons or the materials needed to makethem could present if they fall into the hands of radical states orterrorist groups
2. reduce the numbers of strategic launchers and delivery vehicles, andalso the stockpiles of nuclear warheads and fissile materials.

This article summarizes the security challenges in managing plutoniumand HEU in the U. S. and the former Soviet Union; the programs in placeand their progress to date; and the work that remains to be done to reducethe danger to national and international security that inadequatemanagement of these stockpiles could pose.

Technical Background

The materials that make nuclear bombs are those few isotopes, among thehundreds of isotopes found in nature or producible by technology, that cansustain an explosively growing chain reaction. Two isotopes of uranium fitthis description - U-233 and U-235 - as do all of the isotopes ofplutonium (most importantly Pu-239, Pu-240, Pu-241, and Pu-242).

Nuclear weapons designers prefer plutonium containing more than 90% Pu-239- weapons-grade plutonium. Plutonium which contains only 60-70% Pu-239 iscalled reactor-grade plutonium. However, reactor-grade plutonium can beused to produce nuclear weapons at all levels of technical sophistication.

The quantities of nuclear-explosive material needed to make a nuclear weapon are small - numbers in the range of 4-6 kg are widely cited inunclassified literature as typical. Thus, unless security and accountingsystems are in place, a woker at a nuclear facility could simply putenough material for a bomb in his briefcase and walk out.

The Current Security Challenges

Stockpiles, Rate of Change, and Arms Reductions

Because of unilateral commitments entered into by the United States andthe successor states to the Soviet Union, large fractions of the nucleararsenals of these countries became surplus. Thousands of these weapons arebeing dismantled, containing hundreds of tons of fissile material.

What might these ongoing dismantlements mean for the quantity of fissilematerial that will be surplus? The total estimated stockpiles of the U.S.plutonium and HEU outside of weapons will be 65 tons and 420 tons,respectively. Unclassified estimates suggest that Russia will have 125-165tons of plutonium and 825 tons of HEU outside of weapons.

If the U.S. and Russia are to ensure the "irreversibility of nuclear armsreductions" agreed to by Presidents Clinton and Yeltsin, these reservesand non-strategic warheads will have to be addressed.

Stockpile Vulnerability

Safeguards for securing and accounting for nuclear materials can bedivided into two basic types:

1. domestic safeguards applied by states to their own nuclear materialsto prevent theft of nuclear materials by non-state actors
2. international safeguards implemented by international organizations todetect diversion of nuclear materials from peaceful to military purposes

Today, U.S. systems of securing and accounting for nuclear materials are some of the most stringent in the world. They rely on security technologyto provide effective protection. In contrast to the U.S. approach, theSoviet system was based on loyal and well-paid personnel; today, however,the collapse of the Soviet Union has greatly weakened the pillars of theold system, forcing it to meet challenges it was never designed to face.

Direct Measures to Prevent Theft and Smuggling

Upgrading Security and Accounting at Nuclear Material Sites

Russia has undertaken significant efforts to upgrade security at nuclearsites but has been limited by severe economic constraints. DoE hasestablished a major program to cooperate with the states of the formerSoviet Union in upgrading security and accounting systems at these sites.Today cooperative work is underway at 43 of the 50 locations in the formerSoviet Union; modern safeguards will be in place by 2002.

As the PCAST report concluded, these programs can only succeed if they arebased on geniune cooperation and mutual trust and respect.

Building New Storage Facilities

The U.S. has announced its decision not to build major new storagefacilities for its plutonium and HEU. Russia, by constrast, is cooperatingto build a secure storage facility at the site known as Chelyabinsk-65,now called Ozersk. Another approach to storing some of the 30 tons ofcivilian plutonium is to use the unused concrete-lined rooms in theunderground facility of Krasnoyarsk-26, now known as Zheleznogorsk.

Upgrading Security for Nuclear Weapons Storage Facilities

In this program, Russian experts will determing what is needed, the U.S.will provide equipment, and Russian personnel will do the installation.

Consolidating Storage and Converting Research Reactors

In the U.S. the nuclear-weapons complex is undergoing a substantialconsolidation; research reactors have converted from HEU fuel tolow-enriched fuel (LEU). In Russia, however, consolidation has yet to takehold in a serious way.

Upgrading Transport Security

The U.S. DoD has been providing Russia with warhead-transportationequipment; the Russian Ministry of Defense confirmed that the equipmenthas already substantially improved transport security.

Improving National-Level Regulatory and Accounting Systems

In the U.S., a single computerized data-base - the Nuclear Management andSafeguards System - is kept for accounting of nuclear materialsnationwide. In Russia, the balance of power between the national nuclearregulatory agency - GOSATOMNADZOR - and its subordinates, includingMINATOM, is still developing; DoE and NRC have established promisingprograms of regulatory support.

Creating Tougher International Standards

The NAS recommended that the U.S. pursue international agreements toimprove safeguards and physical security of plutonium and HEU worldwide.

Stopping Nuclear Smuggling

The leaders of the Political Eight countries (the G-7 and Russia)announced an "action plan" on smuggling; however, implementation of theplan has lagged. The U.S. Customs Service has provided limited trainingand simple and cheap equipment for some customs and border patrolofficials, but has had difficulty funding any larger effort.

A comprehensive effort against nuclear smuggling would include:

• Intelligence Cooperation and Information Sharing
• Law Enforcement Units
• Border Controls
• Analysis Centers

Monitored Reductions in Nuclear Weapon and Fissile MaterialStockpiles

Outline of a Comprehensive Regime

1. declarations of stockpiles of nuclear weapons and fissile materials
2. cooperative measures to clarify those declarations (including physicalaccess to production facilities and records for fissile materials)
3. an agreed, monitored halt to additions to these stockpiles
4. agreed, monitored net reductions from these stockpiles

Bilateral Transparency Negotiations

• Inspecting Plutonium and HEU from Dismantled Weapons - not yetimplemented
• Exchanging Nuclear Stockpile Data - not yet implemented
• Comfirming Warhead Dismantlement and Fissile Material Data - nonegotiations pursued since May 1995
• Laying the Legal Basis for Classfied Nuclear Exchanges - agreementalmost completed by late 1995 when Russian government called off talks.
• Nunn-Lugar Storage Site Transparency - no progress made on determingwhat transparency measures there should be
• HEU Purchase Agreement Transparency - transparency measures have beenagreed to provide U.S. high confidence that the LEU it is purchasing infact came from HEU; also assurance that the HEU came from weapons

International Monitoring of Excess Material

Progress is being made towards placing excess material under internationalmonitoring to verify that it is never again returned to weapons, but aswith bilateral transparency efforts, the process has been painfully slow.

Other issues have come up relating IAEA monitoring: who will pay for themonitoring, how to create an irreversible commitment to keep the materialsunder safeguards, how much effort should be placed on monitoring differentmaterials.

Informal Approaches to Transparency Objectives

• Unilateral Openness Initiatives - significant increase in openness isapparent in the U.S. and Russia
• Lab-to-Lab Transparency Technology Development - reports suggest thatthe U.S. and Russia:
  1. resume negotiations to complete agreements about the legal basis for exchanges of classifed nuclear information in 1997
  2. accelerate work on developing measures to verify warhead dismantlementand to inspect plutonium and HEU components arising from dismatlement
  3. develop a credible approach for international verification ofclassified material
  4. make tens of tons of new material eligible for verification in 1997

Limiting Accumulation of Excess Materials

The U.S. and Russia have ceased producing HEU for weapons, and the U.S.has ceased producing weapons plutonium as well. In Russia, 3 militaryplutonium-production reactors continue to operate, providing heat and fuelfor hundreds of thousands of residents. The two sides agreed to convertthe reactors to a new fuel cycle, whose spent fuel would have much lessplutonium.

The second step is a worldwide fissile cutoff convention. However, afterthe UN General Assembly unanimously voted to negotiate this issue, noprogress was made.

Disposition of Excess Fissile Materials

There is now a growing international consensus that, as rapidly aspracticable, physical barriers should be erected that would make itsubstantially more costly, difficult and time consuming ever to re-usethese materials in weapons. Some approaches include:

1. burning the material as fuel in nuclear reactors
2. mixing the material with pre-existing high-level radioactive wastes inan immobilized waste-form for geologic disposal
3. disposing of the material in locations whence recovery is difficult orimpossible

• how quickly the option can be brought into operation
• dangers of diversion of the material to weapons use
• compatibility with wider arms control and nonproliferation goals
• environment, safety, and health
• monetary costs of the disposition operation
• magnitude of technical and timing uncertainties of the foregoingcharacteristics
• comply with existing national regulation with respect to ES&H aspects

Highly Enriched Uranium Disposition

A diposition method which meets end-point security and ES&Hcharacteristics is the blending of HEU with natural or depleted uranium toproduce proliferation-resistant LEU. Both Russia and the United Stateshave decided to use this approach for their excess HEU stockpiles.

Plutonium Disposition: Narrowing the Options

The findings of NAS, a U.S.-Russian joint study and the U.S. DoE suggestthat the two least problematic disposition options, which will renderweapons plutonium as resistant to theft or diversion as reactor-gradeplutonium in commercial spent fuel, are:

• fabrication of plutonium into mixed-oxide fuel for civilian reactors(MOX)
• vitrification of plutonium together with high-level radioactive wastes

Requirements of the Two Preferred Approaches

1. facilities for converting plutonium weapon-component "pits" to oxides- a prototype will be operational at the Los Alamos National Laboratory in1998
2. for the MOX option (over 20 light-water reactors around the world are operational):
   • facilities for fabricating plutonium oxide into MOX fuel
   • reactors capable of safely handling MOX fuel
3. for the immobilization-with-wastes option:
   • facilities for immobilizing plutonium with high-level wastes - 2approaches are being considered: 1) building new immobilization facilitiesfo combined immobilization or 2) immobilizing plutonium and fissionproducts separately in existing facilities

   A version of the second approach, "can-in-canister" is the leadingcontender in DoE's immobilization program, with a net discounted cost ofunder $1 billion.

   Russian Plutonium Disposition and International Cooperation

   While the U.S. is not pursuing a civilian fuel cycle based on plutoniumreprocessing and recycling, Russia will implement a plutonium-recyclingfuel cycle, seeing weapons plutonium and civilian plutonium as essentialparts of that plan. The most fundamental problem with disposition ofplutonium in Russia is money.

   The U.S.-Russian Independent Scientific Commission on Disposition ofExcess Weapons Plutonium found that both the U.S. and Russia shouldimplement the dual-track approach rapidly. The U.S. would support thisapproach with 4 nonproliferation conditions:

   1. international safeguards on the entire process
   2. stringent standards of MPC&A
   3. use of the facility only for excess weapons plutonium
   4. no reprocessing and recycling the resulting spent fuel

   U.S. Controversy Over the "Dual-Track" Decision

   The Bilateral Commission offered arguments for MOX and immobilizationtracks, saying that 2 tracks:

   1. minimize uncertainties and delay
   2. tell Russia and others that U.S. disposition is irreversible
   3. have the best chance of garnering needed long-term support
   4. let the U.S. credibly take part in Russian disposition
   and adressed criticisms:
   1. consistency with U.S. fuel cycle policy
   2. minimal impact on civilian reprocessing programs
   3. risks of nuclear theft comparable to the immobilization approach

   Civil-Military Linkages

   Looking at the implications of the weapons/fuel interchangeability ofplutonium and HEU suggests these conclusions about the links between thecivil and military sides of these matters:

   • the energy-generating potential of suplus military plutonium and HEUis small; thus security considerations not energy considerations shoulddominate in decisions
   • the quantity of separated civilian plutonium is more than half of theworld's military plutonium stockpile, and its existence should be regardedas posing international security challenges

   Reform and Diversification of the Nuclear Cities

   The diversification of the cities' economies is a crucial step. Someprograms of civilian employment are already under way; however thousandsof Russian scientists remain unemployed.

   Conclusions

   The control of plutonium and HEU is perhaps the most serious and urgentsecurity challenge facing the U.S. in the coming decade. Meeting thischallenge will require a comprehensive program of action on many fronts.To succeed, this program will require more energetic leadership andsubstantially higher levels of funding. The costs of failure to act wouldbe far higher than the cost of timely action now.