During the cold war, the US and the Soviet Union each produced enoughfissile material to make tens of thousands of nuclear weapons between 100and 200 metric tons of plutonium and about 1000 tonnes of highly enricheduranium (uranium enriched to more than 20% in U 235).This weapons-usablefissile material seemed invulnerable to theft until the collapse of theSoviet Union in 1991. Since then, subkilogram quantities of plutonium andmultikilogram quantities of highly-enriched uranium have been interceptedin Russia, the Czech Republic and Germany apparently stolen from Russiannuclear facilities and intended for sale. The old Soviet security systemfor fissile material, which focused on the surveillance and control ofthose in contact with such material, has been largely swept away. Gone toois the economic security of nuclear workers, who may now be tempted orthreatened by predatory criminal groups. The situation poses a grave riskto global security, because the biggest obstacle facing non-nuclear-weapons states or even terrorist groups interested inacquiring nuclear weapons is lack of access to the bomb material.

During the last four years, the US along with Western Europe and Japan,has begun to help Moscow strengthen the security of its nuclear warheadsand nuclear materials. Congress began four years ago with the Nunn-Lugarprogram. In the last year and a half the Clinton Administration hasdeveloped a relatively comprehensive set of additional initiatives. (I wasinvolved in these initiatives while working last year in the White HouseOffice of Science and Technology Policy.) Most of the initiatives are inan early stage of implementation, however, and political support for themis at risk in the wake of the Russian army's brutal suppression of theuprising in Chechnya and the Ministry of Atomic Energy's (MinAtom)nuclear-energy contract with Iran. In addition to the nuclear weaponsmaterials one worry about the security of weapons-usable materials at manypoints in the fuel cycles of various types of reactors ln the formerSoviet Union.

The package of initiatives undertaken to address the vulnerabilities ofboth weapons materials and weapons--usable civilian materials in theformer Soviet Union in-cludes efforts to:

• strengthen the security of the existing materials
• stop further production
• dispose of the excess
• increase the "transparency" of warhead and fissile materialmanagement.

Amounts of easily portable weapons-usable fissile material ranging fromsignificant to huge are held under varying levels of security in thefacilities of approximately 100 organizations in the former SovietUnion mostly in Russia. Consider two examples:

At the Mayak spent-nuclear-fuel reprocessing combine, located in theUrals north of Chelyabinsk, plutonium has been recovered from the spentfuel of first-generation Soviet light-water power reactors (of the WER-440type) since 1978. One very ordinary building, built 40 years ago forstorage of chemicals, today contains about 30 tonnes of plutonium in over10 000 thermos-bottle sized containers. Security against penetration byoutsiders appears relatively good, but little thought appears to have beengiven until recently to the possibility that insiders might carrymaterial out of the storage building. Although the facility personnel arecommitted to their responsibilities to safeguard the plutonium, and theclosed city has been somewhat protected from Mafia-type activities, adeputy director of Mayak was mysteriously murdered last October.

Building 116 at the Atomlc Energy in Moscow contains about 70 kilogramsweapons-grade uranium (uranium enriched to more than 90% in U-235) formedinto flat annuli the size of large washers, these are stacked in tubes andused for zero-power criticality tests of a compact reactor designed foruse in space. Yet the wall around the institute is falling down, and untilrecently there was no fence around building 116 and no sensors within itthat could detect unauthorized entry or removal of the material. Alsountil recently, the only basis for an inventory of the quantity ofweapons-usable fissile material at the institute was boxes of old paperreceipts in a dusty room.

The former SovietUnion never developed an adequate materials controlsystem because it had a pervasive central system regulating the movementsof its citizens and monitoring suspicious activities. With that peoplecontrol lsystem now largely swept away (fortunately), the Russiangovernment needs to compensate by introducing the systems of materialprotection, control and accounting that have been developed in the West.

The US government has undertaken two types of initiatives to help do this:a "top down" government-to-government program and a "bottom up" lab-to-labapproach started by the Department of Energy.

Govermnent-to-govenment program. This program was started withinthe Department of Defense with funding from the Nunn-Lugar program (namedafter Sena tors Sam Nunn and Richard Lugar). Congress launched theNunn-Lugar program in October 1991 to assist the former Soviet Union in"the transportation, storage, safeguarding and destruction of nuclear andother weapons [and] the prevention of weapons proliferation."

The Nunn-Lugar program has had some important successes in helpingeliminate surplus missiles and missile silos in the former Soviet Union.However, it has had little direct impact in strengthening the security ofRussian nuclear warheads and materials, because of two DOD policies thatundercut its effectiveness: First, DOD insisted on audit and inspectionrights at the sites where US assistance was being used. Russian hard-liners were thus able to protray the Nunn-Lugar program as a USeffort to buy unilateral access to Russian secret facilities. Second,DOD insisted on using US, rather than Russian, goods and services, asencouraged by the bill authorizing the Nunn-Lugar program. This policydrastically dimin-ished the motivation of the economically stressednuclear sites to cooperate with the program; Russians cynically note thatthe money that a US contractor or consultant spends for a night in aMoscow hotel could support a Russian scientist for a month.

Because of Russian concerns about the intrusiveness of the Nunn-Lugarprogram, it took two years to reach an agreement on a demonstrationsafeguards system, and then only at a plant for fabricating low-enricheduranium fuel in Electrostal, 50 km east of Moscow. Even Electro-stal'sfabrication line for highly enriched uranium fuel was exempted from thismodel safeguards system because it was considered too "sensitive."

To defuse concerns about the potential intrusiveness of US assistance, theClinton Administration decided in the spring of 1994 to offer Russiareciprocal access to US facilities. In July a Russian delegation inspectedthe physical security arrangements at a plutonium storage facility atDOE's Hanford site in the state of Washington. And in October 1994 a USteam was allowed to visit the Mayak plutonium storage facility. AfterwardDOE shipped demonstration equipment to Mayak to strengthen protectionagainst insider diversion threats, including portal detectors sensitiveto the neutron ra-diation from plutonium, two-person access controlsre-quiring personal identification numbers, personnel iden-tificationequipment (hand-geometry and retinal scanners) and video cameras withmotion-detection alarms to monitor the inside of the storage facility.

Following this demonstration of reciprocal access, MinAtom agreed topermit expansion of the government- to-government program into a number ofother facilities handling large quantities of civilian but weapons-usableplutonium and uranium, including the fabrication lines for civilian highlyenriched uranium fuel at Electrostal and Podolsk; the Obninsk Institute ofPhysics and Power Engineering, which designs plutonium breeder reactors;and the Nuclear Research Reactor Institute in Dimitrovgrad, which developsplutonium-containing fuels. In exchange the US government committed anadditional $20 million to the program. This spring, however, after beingadmonished by Congress to drop its nonmilitary activities, DOD transferredto DOE responsibility for fund ing the government-to-government program.

Lab-to-lab Program. Last springDOE also author ized materialssecurity experts at its national laboratories to approach their Russiancounterparts directly to propose joint work on materials security. This"lab-to-lab" program has taken offmore quickly than the government-to-government approach, not surprisingly, because it empowersUS and Russian technical experts to negotiate directly with each other andfor the first time includes US payments for Russian time and equipment.The funding for the lab-to-lab program is ramping up quickly to a proposedlevel of $40 million in 1996. The rule of thumb has been to spendapproximately equal amounts on US salaries, Russian salaries and equipment(Russian and US). For the same money the program can employ about 20 timesas many Russians as Americans.

The lead labs on the Russian side initially have been the KurchatovInstitute, which has been independent of MinAtom since 1992, and MinAtom'scounterpart to Los Alamos National Laboratory, the Institute of Experimental Physics in the closed city of Arzamas-16 (now Kremlev). LastDecember, Kurchatov became the first Russian site to demonstrate, inbuilding 116, a comprehensive upgrade of physical security arrangementsand materials control and accounting procedures.

Arzamas-16 and Los Alamos had begun to collaborate a few years ago onexperiments creating ultrahigh magnetic fields and even before the startof the lab-to-lab program had discussed the possibility of expanding theircooperation into the area of fissile materials control and accounting, inwhich both have relevant technical expertise.

Although MinAtom had insisted on a step-by-step approach to thegovernment-to-government program, when the US proposed such a cautiousapproach in a draft workplan, Arzamas-16 responded last November with amuch bolder plan, which includes in its first 18 months the installationof modern materials-security systems in some of the major Russiannuclear-materials processing and weapons-dismantlement facilities.

Both the government-to-government and lab-to-lab programs have focusedprincipally on facilities under the control of MinAtom. But a large fraction of Russian fissile materials are in nuclear warheads and navalnuclear reactors controlled by the Russian Ministry of Defense. Additionalfacilities dealing with submarine nuclear reactors are operated by theRussian navy and the Committee of the Defense Industry, and researchreactors are run by institutes such as Kurchatov that are not affiliatedwith either MinAtom or the Ministry of Defense. DOE is now attempting tolaunch new cooperative initiatives to address these facilities.

Stopping further production

Given the huge surplus of highly enriched uranium and separated plutonium,it would make sense to have a moratorium on further production. In fact,the rate of production of fissile materials for weapons is already low,and there is hope that it can be halted completely. In September 1993 theUN passed a consensus resolution supporting negotiations for a global banon production of fissile materials for weapons. Negotiations are expectedto begin in Geveva this month.

Russia has shut down most of its 13 military plutonium production reactorsbut continues to operate 3 because they produce by-product heat andelectricity for the populations of the neighboring cities. Unlike thefuel of most civilian power reactors, the aluminum-clad metal fuel used inthese reactors cannot be stored for long periods in water. It must therefore be reprocessed, with the separated plutonium adding to theexisting surplus.

In December 1993 Vice President Gore broached with Russian Prime MinisterChernomyrdin the possibility of a joint Russian-US effort to shut downthese weapons-grade reactors, and the following June the two countriessigned an agreement under which Russia agreed to shut the reactors down bythe year 2000 and to put under bilateral safeguards the plutoniumrecovered from the reactor fuel in the interim. In exchange the US offeredto help provide alternative sources of heat and electricity. However,progress has been slow. The US government hopes that the alternativeenergy sources can be financed by Western investors or internationalbanks, and MinAtom insists that the replacement energy sources be nuclear.The two sides have held joint workshops to consider the possibility thatthe plutonium production reactors could be shifted to a fuel that does notrequire reprocessing and hence would not add to the stores of separatedplutonium. However, the reactors, which are graphite-moderated like thoseat Chernobyl but of an earlier, less safe design should be shut down forsafety reasons as soon as possible in any case.

In addition to the plutonium from production reactors MinAtom is continuing to reprocess spent light-water reactor fuel at Mayak, separating out reactor-grade but weapons-usable plutonium at a rate of 1-2tonnes per year. Given the huge stockpile of already separated civilianand excess weapons plutonium that must be dealt with, it would be safer toleave the unseparated civil plutonium securely stored in spent reactor fuel.

However, MinAtom's principal concern is to ensure the economic future ofthe cities it built. The ministry is therefore seeking prepaid foreignreprocessing contracts to finance the completion of a very large civilianrepro cessing plant at Krasnoyarsk-26 to sustain employment there when themilitary reprocessing plant shuts down.

Helping Russia's plutonium cities find new missions that don't involve theseparation of plutonium should be a high priority for the outside world.

Disposing of the excess

The first initiative to assist Russia in disposing of its surplus weaponsmaterials was proposed by Tom Neff, a physicist at MIT's Center forInternational Studies. In a November 1991 opinion piece in The New YorkTimes, Neff suggested that the US buy Russian uranium after the percentageof the fissile isotope, U-235, had been diluted from an enrichment levelof over 90% to about 4%, the enrichment level used in most power-reactorfuel. The ensuing negotiations became quite com-plex, because Ukrainedemanded some compensation for the uranium that would be derived fromapproximately 2000 Soviet strategic warheads that were based in Ukraine,which are now being shipped to Russia for dismantlement. A deal wasfinally struck in January 1994, and the US contracted to buy from Russia,over a period of 20 years, low-enriched uranium derived from the blendingdown of 500 tonnes of 90% uranium.

The deal has been a troubled one, however, in part because the managementof the US Enrichment Corporation, the government-owned corporation thatoperates the US uranium enrichment plants and was given the exclusive rights to sell the Russian low-enriched uranium, does not like the pricethat the US government negotiated with MinAtom. The US has also had todesign the deal around the restrictions resulting from a suit brought bythe US uranium mining industry, which accused Russia of "dumping" uraniumat low prices on the US market.

The disposal of plutonium is even more difficult. In the case of uranium,one can denature the fuel, that is, render it totally unusable for nuclearweapons, by mixing it with the common uranium isotope U-238, which doesnot chain react. One cannot do the same thing with plutonium, becauseno isotope is available in sufficient quantities to denature the plutonium. Furthermore, the plutonium is not attractive as a fuel fornuclear reactors, because just the cost of making plutonium into fuelwould render it more expensive than the alternative fuel, low-enricheduranium.

In its 1994 report Management and Disposition of Excess WeaponsPlutoniurn, the National Academy of Sciences recommended that the US andRussia move with all deliberate speed to make their excess weaponsplutonium as inaccessible as the tenfold-greater quantities of plutoniumthat will have accumulated in unreprocessed spent power-reactor fuel bythe year 2000. The intense gamma radiation field generated by the fissionproducts in the spent fuel protects such plutonium against theft. So dothe large size and mass of the spent fuel assembly containing plutonium.One spent fuel assembly contains about 5 kg plutonium: The same amount ofplutonium is packed into just two of the thermos-bottle-sized containersof separated plutonium now stored at Mayak.

Building on previous analyses, the NAS report recommended as worthy offurther investigation three options for the disposal of plutonium:

• subsidized use in the fuel of existing US light-water or Canadianheavy-water power reactors
• mixing with the concentrated fission-product waste from which USweapons plutonium was originally separated as that waste is converted intoa low-leachability solid for deep-underground disposal
• emplacement in multikilometer deep boreholes.The DOE is studying these options and soliciting public opinion on them;the agency hopes to have a recommendation in the fall of 1996.

  In Russia, however, MinAtom's first choice is to save its excess separatedplutonium to be used some time in the future as the startup fuel for a newgeneration of 800-megawatt (electric) plutonium breeder reactorsÑalthoughthe construction of the first three such reactors has been suspended since1987 because of lack of funds. Too many sacrifices were involved in theproduction of the plutonium, MinAtom's leaders feel, to treat it as waste.

  While awaiting a resolution to the problem of plutonium disposal, we mustfocus on assuring its secure interim storage. Fortunately DOD and MinAtomhave finally begun to move forward on a collaborative project to build asecure storage facility near the Mayak combine for excess Russian weaponsmaterials. The US has agreed to help build the facility, while Russia haspledged not to recycle the fissile material into new warheads and to letthe US monitor its storage and disposition.

  Verifying declared stockpiles

  It would be easier for the US and Russia to collaborate on improving thesecurity of fissile material if its management were more "transparent,"that is, if each side declared its inventories of nuclear material andallowed the other to make spot checks of these declarations. Increasedtransparency would also make it possible to verify nuclear disarmament. Todate, the verification of nuclear arms reductions has been limited tomissiles, their launchers and bombers. It has not yet been extended towarheads and warhead components.

  At their January 1994 summit Presidents Clinton and Yeltsin agreed tolaunch negotiations on "steps to ensure the transparency andirreversibility of the process of reduction of nuclear weapons." Theinitial focus has been on techniques that would be used to confirm, inreciprocal inspections, declarations of stocks of plutonium "pits" thateach country had accumulated from dismantled warheads. In July 1994 aRussian delegation was invited to the shut-down pit-production facility atRocky Flats, Colorado, to see the techniques the US proposed to use toverify from the outside that a container indeed contained a pit; in Augusta US team saw a similar demonstration at a counterpart facility in theclosed city of Seversk (formerly Tomsk-7).

  The two sides agreed on a procedure that involves measuring a smallportion of the energy spectrum of the gamma rays from the containers todetermine the isotopic makeup of the plutonium, then measuring thespontaneous neutron emission rate to deduce the pit's mass and finallyusing a collimated gamma counter to infer the rough size and shape.Because some of the data that would be revealed by such measurements isclassified, actual implementation of the inspections awaits completion ofan "Agreement of Cooperation" specifying how each country would protectthe other's classified information.

  Last September Clinton and Yeltsin also agreed to begin regularconfidential bilateral exchanges of data on "aggregate stockpiles ofnuclear warheads; on stockpiles of fissile materials and on their safetyand security." Negotiations on such exchanges began this April. To assurethe rest of the world that US and Russian nuclear warhead reductions areirreversible, the two presidents also agreed in January 1994 to considerputting under the safeguards of the International Atomic Energy Agencyfissionable materials released in the process of nuclear disarmament. Asof the end of 1994, the US had unilaterally placed under IAEA safeguardsabout 10 tonnes of highly enriched uranium and plutonium.

  This March Clinton declared that an additional 200 tonnes of highlyenriched uranium and plutonium would be withdrawn from weapons use, butmuch of the material is still in configurations whose shapes areclassified and not yet ready to be submitted to international safeguards.Additional large quantities of excess weapons-grade uranium will probablybe withheld from IAEA safeguards to assure its availability for future usein naval-reactor fuel.

  Thus a rather comprehensive set of initiatives has been undertaken tosecure the huge surpluses of weapons-usable fissile materials that are thelegacies of the cold war and of the dream of an energy economy based onplutonium. The implementation of these critical initiatives has barelybegun; to carry them through will require persistent high-level attentionand adequate resources.