Established 1845

SCIENTIFICAMERICN Jury,e8o Volume 243 Number I

A Ban on the Productionof Fissionable Material for STeapons

Such a "cutoff' could serve two purposes: to stall the furtherbuildup of nucleat arms by the present nuclear-weapons states

and to ptevent their spread to the non-nuclear-weapons states

21-lhe suspension of the SALT III Treaty ratification proceedings in

^ the U.S. Senate, following themilitary intervention of the U.S.S.R.in Afghanistan, does not spell the endof international efforts to restrain thenuclear-arms race between the two su-perpowers. Outside the bilateral SALTprocess various multilateral arms-con-trol negotiations are either in progressor planned, and the Carter Administra-tion has pledged the continued partici-pation of the U.S. in these endeavors.For example, talks are currently underway among representatives of the U.S.,the U.S.S.R. and the U.K. on a compre-hensive treaty to ban all nuclear test ex-plosions. Final preparations are also be-ing made for the second five-year con-ference to review the operation of theNonproliferation Treaty, scheduled toconvene next month in Geneva.

Both the comprehensive test ban andthe Nonproliferation Treaty were putat the top of the list of other impor-tant arms-limitation issues in the jointcommuniqu6 issued by the U.S. and theU.S.S.R. at the time the SALT II Trea-ty was signed last year. That documentstated that "definite progress" had beenmade in the negotiations for a compre-hensive test ban and confirmed the in-teniions of the two superpowers to worktogether with the U.K. "to completepreparation of this treaty as soon as pos-sible." With respect to the Nonprolifera-tion Treaty, President Carter and Presi-dent Brezhnev merely noted "the pro-found threat posed to world security bythe proliferation of nuclear weapons"and agreed that the nuclear-weaponsstates "bear a special responsibility to

by !{rilfiam Epstein

demonstrate restraint" in this regard;they also "affirmed their joint convic-tion that further efforts are needed" tostrengthen the nonproliferation regime.

The two chiefs of state were clearlyright in concluding that further effortsare needed, not least to ensure the suc-cess of the upcoming NonproliferationTreaty Review Conference. The non-nuclear-weapons states are far from im-pressed by the results of SALT II, whicheven if it were to be ratified would nothalt the production of a single new stra-tegic weapon now under developmentand would allow each of the superpow-ers to add thousands of new strategicnuclear warheads to their already exces-sive arsenals. Although most of the non-nuclear-weapons states seem to regardthe SALT II agreement as a step for-ward, they certainly do not consider itadequate compliance with Article VIof the Nonproliferation Treaty, whichcommits the three signatory nuclear-weapons states (the U.S., the U.S.S.R.and the U.K.) to a "cessation of the nu-clear arms race at an early date."

In the circumstances what can bedone to curb both "vertical" prolifera-tion (the increase in the numbers andkinds of nuclear weapons in the hands ofthe nuclear-weapons states) and "hori-zontal" proliferation (the further spreadof nuclear weapons to nations that donot already have them)? In my view,based on more than three decades ofwork on international arms-control mat-ters, there are at present two measuresthat could have a salutary effect not onlyon the strategic-arms competition be-tween the two superpowers but also onthe attitude of the non-nuclear-weapons

states toward the entire nonprolifera-tion regime. One would be the earlyachievement of a Comprehensive TestBan Treaty. The other would be a com-mitment on the part of all concernedparties-nuclear-weapons states andnon-nuclear-weapons states alike-tostart negotiations soon on a treaty toban the production of fissionable mate-rial for nuclear weapons.

]t is hardly necessary to discuss hereI the details of the pending compre-hensive test ban. Since 1963, when the 'Partial Test Ban Treaty (prohibiting nu-clear explosions in the atmosphere, un-der water and in outer space) was con-cluded, a comprehensive test ban hasmeant in effect an underground test ban.The comprehensive test ban has beenthe subject of more discussion and nego-tiation than any other topic in the histo-ry of arms control and disarmament. Inthe text of the Partial Test Ban Treatyand again in the Nonproliferation Trea-ty the three signatory nuclear-weaponsstates promised to seek "the discontin-uance of all test explosions of nuclearweapons for all time." The non-nuclear-weapons states regard the achievementof a comprehensive test ban as a crucialtest of the seriousness of the intentionsof the nuclear-weapons states to halt thenuclear-arms race; it was their chiefdemand at the first NonproliferationTreaty Review Conference, held in Ge-neva in 1975. Indeed, if the nuclear-weapons states had succeeded in achiev-ing a comprehensive test ban in 1963,they might well have avoided the prolif-eration predicament in which they nowfind themselves.

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The damage done then might still bereparable if a comprehensive test bancould be achieved soon. The three nego-tiating parties are said to be very closeto agreement and had expected to bringtheir negotiations to a successful con-clusion soon after the ratification of theSALT II Treaty. Failure to ratify thetreaty could only have an adverse effecton the prospects for a comprehensivetest ban and for nonproliferation.

On the face of it the achievement of acomprehensive test ban would appearto be a comparatively easy step, sincemost of the military benefits likely tobe gained from a large number of nu-clear-weapons tests have already beenincorporated into the nuclear arsenalsof the two superpowers. To be sure,some military officers and nuclear-weap-ons designers on both sides might notwant to see the door closed on all fur-ther nuclear-weapons testing, since theypresumably would like to continue re-fining and improving the large varietyof sophisticated nuclear weapons nowin existence and developing new onesfor future generations of delivery ve-hicles. Any conceivable benefits fromcontinued testing would be insignificant,however, compared with the seriousproliferation risks that would be pre-sented by such a policy.

An equally important step in the di-rection of curbing the arms race, itseems to me, would be to ban the pro-duction of fissionable material for nu-clear weapons. (For most practical pur-poses this means natural uranium en-riched to about 90 percent in the readilyfissionable isotope uranium 235 and re-actor-generated plutonium containing afairly high concentration of the readilyfissionable isotope plutonium 239.) Thisproposal has also been discussed formany years, although no formal negoti-ations on it have ever taken place. Origi-nally the concept was put forward as away to "cut off," or halt, the manufac-ture of weapons-grade fissionable mate-

rial in special military-production facil-ities within the existing nuclear-weap-ons states. In recent years, however, asa number of other countries have ac-quired the capability of producing plu-tonium and enriched uranium in thecourse of their civil nuclear-power pro-grams, it has become more accurate tospeak of a broader prohibition on theproduction of weapons-grade materialby both nuclear-weapons states andnon-nuclear-weapons states. The term"cutoff" has nonetheless continued to beused in arms-control circles to coverboth contingencies.

The proposed production ban wouldbe a logical and feasible next step inthe nuclear-arms-limitation process. In-deed, the problems involved in its nego-tiation would be fairly simple, particu-larly when they are compared with thespecial difficulties and complexities fac-ing any future SALT negotiations. Moreimportant, a treaty incorporating such aban would help to restrain both the ver-tical and the horizontal proliferation ofnuclear weapons. The confluence of anumber of circumstances has made thetime ripe for this step. Accordingly itshould be put at the top of the interna-tional arms-control agenda, on a parwith the comprehensive test ban.

fhe idea of a cutoff in the produc-r tion of fissionable material for weap-

ons purposes was first put forwardin President Eisenhower's "Atoms forPeace" address to the General Assem-bly of the United Nations in 1953. ThePresident's proposal, which arose out ofthe failure of the postwar Baruch planfor the international control of atomicenergy, incorporated not only the ideaof a production cutoff but also a call for"contributions from the stockpiles ofnormal uranium and fissionable mate-rial" to a new international agency em-powered to promote and regulate the useof atomic energy for peaceful purposes.(This part of the proposal led to the es-

tablishment of the International AtomicEnergy Agency, or IAEA, in 1957.)

The officials responsible for the Amer-ican "Atoms for Peace" proposal wereattempting a new approach to nuclear-arms control and disarmament. They ad-vanced the idea of the cutoff as a wayof placing a ceiling on the amount offissionable material available for nucle-ar weapons and hence on the total num-ber of nuclear weapons that could bemade, and they viewed the transfer ofsuch material from military stockpilesto the new international agency as a wayof beginning to reduce the total numberof nuclear weapons already in existence.They regarded the two parts of theproposal as interrelated measures thatcould proceed in parallel with other ef-forts to prevent the further proliferationof nuclear weapons both vertically andhorizontally.

In 1956 Secretary of State Dulles, act-ing on behalf of the U.S., the U.K., Can-ada and France, presented a workingpaper titled "Proposals for Partial Mea-sures of Disarmament" to the five-mem-ber subcommittee of the UN Disarma-ment Commission, which was then meet-ing in London. Among the provisionsincluded in the working paper was theproposal that "all future production offissionable material will be used underinternational supervision, exclusivelyfor non-weapons purposes," and that"the parties undertake to provide, underinternational supervision, for equitabletransfers, in successive increments, offissionable material from previous pro-duction to non-weapons purposes." TheU.S.S.R. rejected the working paper inits entirety on the grounds that such aban on the production of fissionablematerial for nuclear weapons withoutthe outlawing of nuclear weapons them-selves would be impractical.

The following year the UN GeneralAssembly adopted, over the oppositionof the U.S.S.R., a resolution based ona U.S.-sponsored draft that urged the

URANIUM in its natural state (left't consists almost entirely of theisotope uranium 238, with a small admixture (.7 percent) of the readi-ly fissionable isotope uranium 235. Low-enriched uranium suitable

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for use as a fuel in a typical nuclear-power re etor (center) containsapproximately 3.3 percent uranium 235. High-enriched weapons-grade uranium (rightl contains more than 90 percent uraniurn 235,

u-238 (99.3%) U-235 (.7'")

NATURAL URANIUM

u-238 (96.7%) u-23s (3 3q:)

REACTOR-GRADE URANIUM

u-238 (1096) U-235 (90''.)

WEAPONS.GRADE URANIUM

member states to give priority to a dis-armament agreement providing for anumber of partial disarmament mea-sures, including "the cessation of theproduction of fissionable material forweapons purposes." That was the firsttime the General Assembly had adoptedany resolution dealing specifically withthe cutoff.

The issue was raised again in 1964,when President Johnson, in a message tothe UN Committee on Disarmament,proposed a "freeze" on the nuclear-arms race, accompanied by a separateagreement for a cutoff that could beginwith verified plant-by-plant shutdowns.Later that year the U.S., the U.S.S.R.and the U.K. separately announced theirunilateral decision for an immediate re-duction (or "cutback") in the productionof fissionable material for weapons pur-poses. The U.S. explained that its unilat-eral curtailment of the production of fis-sionable material, to be carried out overa period of four years, would (whenadded to previous reductions) representoverall decreases of 20 percent in theproduction of plutonium and 40 percentin the output of enriched uranium. TheU.S.S.R. in turn announced its decisionto stop forthwith the construction oftwo large reactors for the production ofplutonium, to reduce substantially overthe next few years the production of ura-nium 235 for nuclear weapons and toallocate more fissionable material forpeaceful uses. The U.K. responded bypointing out that it had pursued a policyalong the same lines; it had earlier an-nounced its production of uranium 23,5had ceased and its output of plutoniumwas ending gradually. It is noteworthythat none of the three parties ever com-plained that any of the others had failedto abide by its unilateral promises.

The U.S. subsequently submitted adetailed working paper in support ofa complete cutoff, outlining nonintru-sive verification procedures and propos-ing that it convert 60,000 kilograms offissionable material (and the U.S.S.R.40,000 kilograms) to peaceful purpos-es. The U.S.S.R. again expressed doubtabout whether a separate agreement ona cutoff was possible outside of a gener-al disarmament agreement.

f t is not surprising that rhe U.S.S.R. op-r posed the proposal for a cutoff in the1950's and 1960's. All nuclear powersrestrict information about the size oftheir stockpiles of fissionable plutoniumand enriched uranium, and they contin-ue to guard this information as a mili-tary secret. The possession of such in-formation u'ould give an adversary anaccurate basis for estimating the size ofa nation's nuclear arsenal. It was gener-ally recognized at the time, however,that the U.S., with its long head startand greater technical competence, hadstockpiled far more fissionable materi-al than the U.S.S.R. Hence any cutoff

1,OOO KILOGRAMS OF WEAPONS-GRADEURANIUM : 3O,OOO KILOGRAMS OFREACTOR.GRADE URANIUM

in the 1950's or 1960's, even if it hadbeen accompanied by larger transfersof U.S. material from military stock-piles to peaceful purposes, would sure-ly have worked to the disadvantage ofthe U.S.S.R.

The U.S. persisted, however, and in1966 presented three working papersoutlining in further detail proposals forthe transfer of fissionable material ob-tained from the destruction of nuclearweapons and for the provision of inspec-tion systems to monitor shut-down plu-tonium-production facilities and shut-down nuclear reactors. The matter wasnot pursued for the next two years, how-ever, because both the U.S. and theU.S.S.R. had in the meantime becomepreoccupied with negotiating an agree-ment on the Nonproliferation Treaty.

In 1969 the U.S. again stressed the im-portance of the cutoff. President Nixonlisted it, along with a ComprehensiveTest Ban Treaty, as one of the items theU.S. would press for in the Genevameetings of the Committee on Disar-mament. In order to meet the objectionsof the U.S.S.R. to the verification pro-visions proposed earlier, the U.S. an-nounced that it would no longer ask for"adversary inspection" under a cutoffagreement but would rely on the IAEAsafeguards system. The Nixon Adminis-tration had evidently reached the con-clusion that the IAEA safegudrds sys-tem, even if it was applied only to "de-clared" facilities or to shut-down ones,would provide adequate verification ofRussian compliance. The U.S. also em-phasized that in the context of a cutoffagreement the nuclear-weapons statescould accept the same IAEA safeguards

as were required for the non-nuclear-weapons states under the Nonprolif-eration Treaty. Finally, the U.S. main-tained, the Russian argument that a cut-off would not be worthwhile because itdid not deal with existing nuclear weap-ons was invalid; it was tantamount tosaying no steps toward halting the armsrace were worthwhile if they did notcompletely eliminate existing nucleararsenals, a thesis that was unacceptable.The U.S.S.R. remained adamant in spiteof the fact the new American approachreceived wide support among the non-aligned countries.

After the beginning of the SALT ne-gotiations in 1969 the issue of multi-lateral negotiations for a cutoff (and in-deed for most other nuclear-arms-limi-tation measures) was treated as if it hadlost its urgency, and it lapsed into abey-ance. It was not until the UN SpecialSession on Disarmament almost a dec-ade later that the idea of a cutoff wasrevived.

f he UN Special Session on Disarma-I ment, held in New York in May andJune of 1978, was the largest conferenceof its kind ever convened. It was attend-ed by 20 heads of government, fourvice-presidents or deputy prime minis-ters and 49 foreign ministers. After sixweeks of debate and intensive negotia-tions the session reached a consensuson a lengthy final document containinga declaration of principles, a programof action for disarmament and an im-proved procedural mechanism for nego-tiations.

Several participating countries sup-ported the cutoff as a promising mea-

coNvERsIoN of 1,000 kilograms of stockpiled weapons-grade uranium to peaceful pur-poses would yield some 301000 kilograms of reactor-grade uranium, enough to fuel a 11000-megawatt power reactor of the light-water type for approximately a year. The exact amount ofweapons'grade fissionable material currently set aside in the military stockpiles of the nuclear-weaPons states is of course not a rnatter of public knowledge. Some idea of tbe potential sup-ply of nuclear fuel from this source, however, can be gathered from tbe fact that in 1954 tfeU.S. oftered to transfer 601000 kilograms of fissionable material from its military stockpiles iopeaceful uses, if the u.s.s.R, woutd similarly convert 40,000 kilograms. The u.s.s,R., ,"Li"h atthat time had far less weapons-grade material on hand than thJ U.S., turned down the ofier.

u-238

45

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sure of nuclear-arms limitation. Oneof the strongest proponents was PrimeMinister Trudeau of Canada, who out-lined a four-point strategy to "suffo-cate" the nuclear-arms race, a strategyconsisting of a comprehensive nuclear-test ban, a ban on the flight testing of allnew strategic delivery systems, a ban onthe production of fissionable materialfor weapons purposes and a reduction inmilitary expenditures on new strategic-weapons systems. Concerning the cutoffhe said: "The efect of this would be toset a finite limit on the availability ofnuclear-weapons material. ... It wouldhave the great advantage of placingnuclear-weapons states on a muchmore comparable basis with non-nucle-ar-weapons states than they have beenthus far under the dispensation of theNon-Proliferation Treaty." As eventu-ally agreed to by the special session, thefinal document called for a "cessationof the production of all types of nucle-ar weapons and their means of delivery,and of the production of fissionable ma-terial for weapons purposes."

At the regular session of the GeneralAssembly in the fall of 1978 Canadafollowed up the initiative of its primeminister by proposing a resolution onthe cutoff as an important measure bothfor limiting the nuclear-arms race andfor preventing the further proliferationof nuclear weapons. The resolutionasked that the Committee on Disar-mament, at an appropriate stage of itswork, consider urgently "an adequatelyverified cessation and prohibition of theproduction of fissionable material forweapons purposes and other nuclearexplosive devices." The language of theproposed cutoff thus explicitly coveredboth the cessation of current productionand the prohibition of new production;in addition it was deliberately extendedto ban all "peaceful" nuclear explosives.The U.S.S.R. and the other members ofthe Warsaw Pact bloc (except Romania)opposed the resolution as not going farenough, since it did not also call for ahalt in the production of nuclear weap-ons. The U.S. and the U.K., althoughthey were no longer such strong advo-cates of the cutoff as they had once been,voted for the resolution, and it wasadopted by an overwhelming majorityof the nations present and voting. At the1979 session of the General Assembly,Canada again proposed a resolutioncalling on the Committee on Disarma-ment to pursue its consideration of thecutoff, and the resolution was adoptedby a vote even larger than the one in1978. These large affirmative votes haveencouraged Canada to continue to pressfor the cutoff, which is once again clear-ly an outstanding item on the interna-tional agenda of disarmament issues.

Tt is not clear why the U.S. should nowI demonstrate less enthusiasm for anarms-limitation measure it had initiated

0 110 330 s50 770 990DAYS IN REACTOR

PLUTONIUM 239, another readily fssionable isotope widely used in the fabrication of nucle-tr weapons, is created in a typical uranium-fueled reactor as the end product of a particularsequence of nuclear reactions in which a nucleus of uraniurn 23E in the initial fuel captures aneutron, becoming uranium 239, which then decays radioactively in two steps to yield pluto-nium 239. A nucleus of plutonium 239 may in turn fssion when it is struck by a neutron, or itmay absorb the neutron to become ptutonium 240. The leveling oft of the production curve forplutonium 239 means that at the end of the eftective life of the fuel toad iir a typical pressur-ized-water reactor this isotope is being consumed ahnost as fast as it is being created. Plutoni-tm 241, the product of neutron capture by plutonium 240, may also fission, or it may captureanother neutron to become plutonium 242. Weapons-grade plutonium, loosely ilefined as plu-tonium containing a high concentratibn of plutonium 239, is obtained from'special military-production reactors simply by removing the fuel elements from the reactor core after a compar-ativety sbort sburnuptt time. Under certain circumstances, however, reactor-grade plutonium(obtaineil after a burnup time of three years, say) could also be used to make nuclear explo-sives; special provisions would therefore have to be incorporated in any international agree-ment prohibiting the production of this material for the purpose of making nuclear lyeapons.

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and ardently supported for more thantwo decades. It is of course possible thatfor the thousands of new warheads itwill be allowed to manufacture underthe SALT II Treaty even the massivestockpile of weapons-grade fissionablematerial the U.S. has built up over theyears may be thought by some to be in-adequate. When one remembers, how-ever, that the U.S.'s unilateral cutback inthe production of fissionable material in1964 amounted to a decrease in produc-tion of 20 percent for plutonium and 40percent for highly enriched uranium,and that in addition the U.S. offered toconvert 60,000 kilograms of such mate-rial (enough to make thousands of nu-clear warheads) from military uses topeaceful ones, it is difficult to believe theU.S. might now fear a shortage of nucle-ar explosive material. It seems reason-able to look elsewhere for the real mo-tivation.

Of course, any proposal as far-reach-ing as a ban on the production of fission-able material for nuclear weapons canbe expected to stir up opposition basedon perceived or imagined strategic ineq-uities. The old specter of the U.S.S.R.'sgaining some advantage would no doubtbe resurrected. Actually it is the Rus-sians who might still be concerned aboutthe possibility that the U.S. could gainsome advantage as the result of a cutoff.At the time the SALT II Treaty wassigned the U.S. had close to 10,000 stra-tegic warheads and bombs, whereas theU.S.S.R. was reported to have about5,000. Under the terms of the treatyeach of the two powers would be legallyentitled to build up to a maximum ofsome 17,000 strategic warheads andbombs by 1985, although neither appar-ently intends to build that many. Cur-rent plans are for the American arsenalto increase to about 13,000 warheadsand for the Russian arsenal to increaseto about 10,000 warheads. (In additionthe U.S. is reported to have some 22,-000 tactical nuclear weapons and theU.S.S.R. a somewhat smaller number.)

In neither case, however, would therebe any real cause for concern that oneside would gain any advantage over theother as a result of a cutoff. The SALT IITreaty has fixed equal overall ceilingsfor strategic launchers and warheads.Any cutoff agreement, if it is to be ac-ceptable, would also have to provideequal ceilings for both powers. If thereis some disparity between the presentstockpiles of weapons-grade fissionablematerial, it could be adjusted by asym-metrical conversion and transfers frommilitary purposes to peaceful ones.Therefore, whereas a cutoff coupledwith a transfer of military material topeaceful purposes in the period of the1950's and 1960's might not have helpedto stabilize the nuclear balance betweenthe two superpowers, in today's circum-stances it would help. In addition if theinitial production ban and transfers pro-

ceeded according to agreement, fu-ture transfers could be progressively in-creased and could provide another wayof achieving actual reductions in stra-tegic nuclear weapons. Thus the cutoffcould become a significant disarmamentmeasure in itself.

Questions would no doubt be raisedabout the adequacy of verification ofsuch a production ban. Because of theremarkable progress made in the pasttwo decades in satellite surveillance andother "national technical means," verifi-cation no longer presents the same prob-lems it once did, in terms of either effec-tiveness or intrusiveness. That was un-doubtedly a factor in the decision byPresident Nixon to abandon adversaryinspection in 1969 and to rely on the lessonerous international safeguards sys-tem of the IAEA for declared plantsand facilities that were to be shut down.Modern means of verification would en-sure that the large plants and facilitiesneeded to produce significant quantitiesof hiehly enriched uranium and plutoni-um could not escape detection. Even thesecret diversion of spent fuel from pow'er reactors to the production of plutoni-um, or the development of new proces-ses for enriching uranium, which mightallow the secret production of weapons-grade fissionable material in small clan-destine installations, would not createany serious instability in the nuclearbalance between the superpowers. Theamounts that could be produced secret-ly in this way would be so small as tomake no real difference, considering themagnitude of the existing American andRussian stockpiles.

QRecial attention would have to be giv-tJ en to the problems of verificationthat would arise in connection withthe production of plutonium. Althoughpure plutonium 239 is the most efficientweapons-grade flssionable material, itcan be exploded even when it is in amixture with smaller amounts of otherfissionable and nonfissionable plutoni-um isotopes. Furthermore, it is extreme-ly difficult to deliberately "denature"plutonium 239. Even when it is associat-ed with oxides and isotopes of other ele-ments, the plutonium can be extractedfrom spent reactor fuel by variouschemical-separation techniques. Theverification problem would be compli-cated further, of course, if the worldwere to move in the direction of a "plu-tonium economy" through the wide-spread adoption of plutonium recyclingand breeder reactors.

Two different approaches to dealingwith this prpblem have been put for-ward. A number of observers have sug-gested that all reprocessing of plutoni-um be stopped, a solution that in itselfcreates many problems. The other ap-proach that has been proposed is toplace all plutonium under IAEA safe-guards and all plutonium stockpiles in

IAEA custody. This would require thatthe IAEA safeguards, which are nowbased on accounting, containment andsurveillance systems and periodic on-site inspections, be strengthened andthat special stockpiling facilities be es-tablished. Whichever approach is adopt-ed, the details of any system that calledfor the veriflcation of a ban on the pro-duction of weapons-grade plutonium,or for its control in special cases (suchas its use as a fuel in certain nuclearreactors or in nuclear-powered subma-rines and other ships), would have to becarefully negotiated, and special rulesand precautions would be required. Thesame would be true of highly enricheduranium produced for special nonex-plosive purposes. In any case full usecould also be made of national techni-cal means of verification and of consul-tative commissions to deal with ambig-uous events, following the precedent setin the various SALT agreements.

Another problem would arise if, asseems likely, China and France wouldnot agree to a cutoff. Both countrieshave repeatedly insisted they would notagree to a comprehensive test ban untilthey closed or at least reduced the nucle-ar-weapons gap between them and thesuperpowers. They would no doubt takethe same position with respect to a cut-off. China and France are so far behindin nuclear weaponry, however, that for anumber of years it would make little dif-ference from the point of view of thesuperpowers whether these two second-ary nuclear powers agreed or not. TheU.S., the U.S.S.R. and the U.K. werewilling to conclude the 1963 Partial TestBan Treaty and the NonproliferationTreaty (and to negotiate a comprehen-sive test ban) without the participationof China and France. They should beequally willing and able, without jeopar-dizing their security or undermining nu-clear deterrence, to agree to a cutoffwithout China and France, in the expec-tation that eventually these two hold-outs would also agree. Indeed, any cut-off agreement would almost certainlyinclude what has now become a custom-ary provision of arms-control treaties,namely calling for a review of the opera-tion of the treaty after a stated period ofyears to evaluate how expectations havebeen fulfilled.

It might also be argued that a cutoffand the beginning of nuclear disarma-ment would result in a massive buildupof conventional arms, which could leadto a large increase in military expendi-tures. In the first place, it must be reit-erated that, dangerous and destructivethough conventional weapons are, theydo not present anything like the threat tocivilization and human survival that nu-clear weapons do; it would take yearsfor any conventional war to cause thedestruction that could be inflicted inhours or even minutes by a nuclear war.Moreover, this argument tends to ignore

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the vastly different world climate thatwould be produced by any sign of realrestraint in the nuclear-arms race. Theresulting reduction of fears and ten-sions, the revival of d6tente between theU.S. and the U.S.S.R. and increased in-ternational confidence could lead togreater international cooperation andmight create the conditions where far-reaching measures of conventional dis-armament as well as of nuclear disarma-ment would become possible. There isof course no guarantee this would bethe result; history shows, however, thatthe continuing development of nuclearweapons does not lead to conventionaldisarmament but rather feeds the armsrace in both directions.

Finally, it could be argued that a cut-off would not end the nuclear-arms racebecause the U.S. and the U.S.S.R. couldstill conduct a technological race to in-crease the accuracy and effectivenessof their delivery systems, presenting aneven greater threat to deterrence andinternational security than the mereproduction and accumulation of moreweapons. The cutoff by itself would nothalt research and development, or themodernization of nuclear systems or

the transfer of fissionable material fromolder to newer types of nuclear war-heads. Therefore unless it were followedby more direct measures for nuclear dis-armament and by curbs on new techno-logical developments (such as a ban onunderground nuclear tests) the impactof a production ban would in time be-gin to lose its effect.

These arguments have some merit.They could of course be equally appliedto a ban on the production of addition-al nuclear weapons. Nevertheless, thereare a variety of indirect benefits to behad from limiting the amount of nucle-ar-explosive material and reversing theopen-ended race to increase the numberof nuclear weapons. As the U.S. arguedin 1969, it is an unacceptable thesis tomaintain that intermediate steps towardhalting the arms race are not useful ifthey do not completely eliminate all nu-clear weapons. In order to reverse anyrace it is first necessary to bring it to ahalt. Furthermore, the very act of end-ing the production of explosive materialnecessary to produce additional weap-ons could create a more favorable cli-mate for ending the production of addi-tional nuclear weapons.

The successful verification of a cutoffwould have great psychological and po-litical importance. It might profoundlyaffect conventional beliefs that nothingcan be done to halt the arms race. Itwould have some effect in de-emphasiz-ing the importance of nuclear weaponsin international relations and could leadto a significant reduction in tensions be-tween the U.S. and the U.S.S.R. It couldalso provide a demonstration in interna-tional verification that would be usefulfor other measures of nuclear-arms con-trol and disarmament.

[t present 114 countries are parties to,( \ the Nonproliferation Treaty, leav-ing more than 40 that are not. Most ofthe latter have no capability or desire to"go nuclear," but a number of them al-ready have or will soon have such capa-bility; they include not only India, whichhas already exploded a nuclear device,but also Pakistan, Israel, Egypt, SouthAfrica, Spain, Argentina and Brazil.Among the countries that are parties tothe Nonproliferation Treaty some threedozen are potential nuclear-weaponspowers. Under the terms of the treatythey can withdraw on three months' no-tice if they feel their vital interests are injeopardy. Whether any of them decideto withdraw and go nuclear will dependin part on whether any other non-nucle-ar-weapons states (and which ones) de-cide to acquire nuclear weapons. It istherefore of crucial importance for allstates interested in strengthening thenonproliferation regime to do every-thing possible to reduce the incentivesfor additional states to go nuclear.

There are a number of things the nu-clear-weapons states can do in this re-gard, one of which is the cessation oftheir vertical proliferation of nuclearweapons, which will take some time toachieve. A more immediate step wouldbe the elimination, or reduction to theextent possible, of the discriminatory el-ements of the Nonproliferation Treaty.When this agreement was being negoti-ated in the 1960's, many of the non-nu-clear-weapons states were uneasy aboutthe inherent imbalance of the treaty,which decreed a permanent division ofthe states of the world into two catego-ries: those with nuclear weapons andthose without them. Most countrieswere willing to accept the situation as atemporary fact of international life, pro-vided that the nuclear-weapons statescommitted themselves to halting and re-versing the nuclear-arms race (accord-ing to Article VI of the treaty) and assist-ing the non-nuclear-weapons states inthe development of the peaceful usesof nuclear energy (according to ArticleIV). The problem of the lack of equalrights and obligations between nuclear-weapons states and non-nuclear-weap-ons states was made more difficult bythe provisions of the treaty that requiredonly non-nuclear-weapons states to sub-

6trooJ5oo

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100coNcENTRATtON OF FISSTONABLE MATERTAL (PERCENT)

CRITICAL MASS of fssionable material needed to produce a nuclear explosive is the smaltestamount in which a chain reaction can be sustained by fast neutrons alone. The critical massdepends on a number of factors, including the pbysical purity of the material in question. For agiven material the critical mass is smallest when the fissionable material is in its pure isotopicform, and it is sunounded by a suitable neutron-reflecting materiat, such as natural uranium.(A critical mass of 4.4 kilograms of 100 percent plutonium 239, plotted here under those condi-tions, would be about the size of an orange.) The variation of critical mass with concentrationof fissionable material in it is obviously less pronounced for plutonium than it is for uranium.

48

ject their entire nuclear programs to thesafeguards system of the IAEA. So greatwas the resentment of the non-nuclear-weapons states over what many of themregarded as an inequitable and discrimi-natory situation that the U.S. and theU.K. (but not the U.S.S.R.) agreed vol-untarily io accept IAEA safeguardsover their nonmilitary nuclear pro-grams and facilities. Although this con-cession went some way toward achiev-ing greater balance between the two cat-egories of states, it did not go far enoughto satisfy such countries as India, Braziland Argentina, which continue to regardthe treaty as discriminatory.

Even the non-nuclear-weapons statesthat are parties to the NonproliferationTreaty are dissatisfied with what theyconsider the failure of the nuclear-weapons states to carry out their com-mitments under the terms of the treaty.At the first Nonproliferation Treaty Re-view Conference in 1975 the nonalignednon-nuclear-weapons states (known asthe Group of 77) were insistent in theirdemands that the nuclear-weaponsstates live up to their commitments andthat in addition they provide security as-surances to the non-nuclear-weaponsstates by pledging not to use or threatento use nuclear weapons against them.The compromise declaration that wasfinally adopted by consensus left mostof the non-nuclear-weapons states dis-satisfied.

fn the five years that have passed sincer the first Nonproliferation Treaty Re-view Conference little progress has beenmade in satisfying the demands of thenon-nuclear-weapons states. Althoughthe member states of the Nuclear Sup-pliers Group, which met in London af-ter 1975, did succeed, on their own ini-tiative and in their own interests, inagreeing to tighten the restrictions andsafeguards on the export of nuclear ma-terial and equipment, the non-nuclear-weapons states tended to regard this as aone-sided effort that would intensify thediscriminatory aspects of the non-pro-lileration regime. The International Nu-clear Fuel Cycle Evaluation (INFCE)has just completed a detailed two-yearinquiry, with the participation of boththe importing countries and the suppli-ers, inio the many problems of nuclearenergy and their relation to nuclear-weapons proliferation. The INFCE re-port, which was released in February,contains a great deal of valuable infor-ination and analysis. It was strictly atechnical study, however, not a politicalone. Accordingly it has not yielded anysolutions to the main problems of nucle-ar energy and nuclear-weapons prolifer-ation, which are largely political in na-ture. Only a combination of both techni-cal and political measures holds out anypromise of success in halting the furtherproliferation of nuclear weapons.

Many of the political measures re-

quired are related to halting and revers-ing the vertical proliferation of nuclearweapons as a way of facilitating effortsto prevent their horizontal proliferation.In this context the most important im-mediate steps that could be taken wouldbe the comprehensive test ban and thecutoff. The impact of a comprehensivetest ban is obvious: it would place thenuclear-weapons states and the non-nu-clear-weapons states on a more equalfooting if both were barred from con-ducting any nuclear explosions of eithera military or a peaceful nature; it wou!:dalso constitute an effective curb on thetechnological improvement of nuclearwarheads. Finally, it would have an im-mediate symbolic and psychological ef-fect by demonstrating the willingness ofthe nuclear-weapons states to acceptsome limitation on the qualitative nu-clear-arms race.

The impact of the cutoff, which wouldbe similar to that of the comprehensivetest ban, requires more explanation. Itwould, of course, still be possible for thenuclear-weapons states to produce ad-ditional nuclear warheads from theirstockpiles of fissionable material or totransfer explosive material from larg-er to smaller warheads or from olderto newer ones. The cutoff would still,however, constitute an important steptoward curbing the vertical prolifera-tion of nuclear weapons; it would slowthe production of nuclear weapons andcould be a very useful step toward actu-ally ending the production of all nuclearweapons. It would therefore help to re-duce the discriminatory features of theNonproliferation Treaty.

Moreover, once the production of fis-sionable material for weapons purposeswas halted, future production of fis-sionable material would have to be forpeaceful civilian purposes. As the U.S.stressed in 1969, this would make it pos-sible for the nuclear-weapons states toaccept the same IAEA safeguards thatwere required of the non-nuclear-weap-ons states under the NonproliferationTreaty, since there would be few mili-tary secrets to protect. Thus at a strokeone of the most irritating elements ofdiscrimination between the nuclear-weapons states and the non-nuclear-weapons states could be removed. Spe-cial precautions would have to be takenso that certain secrets of uranium en-richment would not be disclosed, butthese need not be much different fromthe precautions now taken under IAEAsafeguards to prevent the disclosure oftechnological and commercial secrets inthe case of peaceful nuclear reactorsand facilities. If additional verificationprocedures were required to ensure thaturanium-enrichment and plutonium-re-processing plants in the nuclear-weap-ons states were not being used to pro-duce fissionable material for nuclearweapons, these procedures would be anecessary concomitant of the greater

nuclear capabilities of the nuclear-weapons states and would not detractfrom the essential equity of the treaty, aslong as the safeguards on the nuclear-weapons states were no less thorough oreffective than those on the non-nuclear-weapons states.

By taking a concrete step toward nu-clear-arms limitation and reduction, byholding out hope for further measuresof nuclear disarmament and by remov-ing the unequal treatment regardinginternational safeguards, the proposedproduction ban could help to strength-en the Nonproliferation Treaty and re-move or at least weaken some of thearguments used against it. If a cutoffagreement were negotiated as a multi-lateral treaty, it would constitute a di-rect legal barrier to the spread of nucle-ar weapons to additional countries thataccepted the treaty. In order for such atreaty to apply to non-nuclear-weaponsstates that were producing fissionablematerial, it would have to provide forthe prohibition as well as the cessationof the production of fissionable materialfor weapons purposes and for other nu-clear explosive devices. A prohibition ofthis kind would go considerably beyondthe provisions of the NonproliferationTreaty and the pending comprehensivetest ban in imposing a prior legal barrierto the spread of nuclear weapons andexplosive devices to countries that donot yet have them. If the treaty were toprovide for safeguards to be appliedequitably to both nuclear-weaponsstates and non-nuclear-weapons states,and also for the conversion and transferof existing stocks of weapons-grade fis-sionable material to peaceful civilianuses, in particular for the benefit of thenon-nuclear-weapons states, then theseprovisions would serve as incentives fornon-nuclear-weapons states to becomeparties to it.

fhere are several different optionsr that could be pursued in negotiating

a ban on the production of fissionablematerial for nuclear weapons. Ideally itwould be better if it could be negotiatedfrom the beginning as a multilateraltreaty covering both nuclear-weaponsstates and non-nuclear-weapons states.From the practical point of view, how-ever, it might be necessary to begin on abilateral basis between the two super-powers or on a trilateral basis, includingthe U.K. Any preliminary agreementreached in this way could be submittedto the Geneva Committee on Disarma-ment so that the non-nuclear-weaponsstates would have an opportunity for afuli discussion and review of the treaty;the agreement could then be submittedto the UN General Assembly. Hence allstates would be able to participate in theelaboration of the treaty, a procedurethat would facilitate the widest possibleadherence to it.

The verification procedures applied

49

to tlre nuclear-weapons states could pro-vide in the first instance for completeplant-by-plant shutdowns on a recip-rocal or matching basis, as the U.S.proposed in the 1960's, with availableverification techniques, including thevarious national technical means of ver-ification. The more complex proceduresrcquired for ensuring the conversionof u'eapons-grade fissionable material topeaceful uses could be verified by theIAEA safeguards system, which nowmonitors all the nonmilitary nuclearfacilities of the non-nuclear-weaponsstates under the terms of the Nonprolif-eration Treaty. Special, more stringentprocedures would have to be negotiatedfor the nuclear-weapons states in co-opcration with the IAEA with respect10 the various problem areas discussedirbove. Procedures would also have tobe worked out for the conversion of mil-itary stocks to peaceful purposes.

Another option open to the U.S.would be to take the initiative on a cut-off unilaterally. Because of the painfullyslow pace of negotiations for any inter-national agreement and the complica-tions of obtaining Senate approval, thcrcis much to be said for a unilateral ap-proach. There is also ample precedentfor such national action intended to fa-cilitate international reciprocal actionor negotiations. The U.S. might u,ellconsider repeating its initiati\,'e of 196.t,when it unilaterally announced a cut-back of its production of fissionablematerial for weapons and invited theU.S.S.R. to reciprocate. This U.S. actionled to the mutual cutbacks announcedby the U.S.S.R. and the U.K., whichcame to be known as "reciprocated uni-lateral acts" or, as the Russians callcdthe process, action by "mutual example."

In a similar action President Nixonannounced in 1969 the unilateral deci-

sion of the U.S. to renounce all use ofbiological agents and weapons, to stopthe production of all biological agentsfor weapons purposes, to dispose of allexisting stocks of biological weaponsand to confinc all future biological re-search to defensive purposes. The U.S.hoped that other states too would re-nounce biological weapons, and it urgedthat such decisions be converted into in-ternational legal obligations through aconvention of some kind. This unilateralaction by the U.S. led to the negotiationand successful conclusion in I 972 of theConvention on rhe Prohibition of theDevelopment, Production and Stock-piling of Bacteriological (Biological)and Toxin Weapons and on Their De-struction.

A unilateral curoff by the U.S. of theproduction of fissionable material for\\'eapons purposes, at least in the formof a suspension, ri'ould not appear to

SOUTH AFRICA'

POTENTIAL NUCLEAR-WEAPONS STATES, shown in difier-ent shades of color on this world map, could each have the technicalcapability of exploding a nuclear device by 1990, if they should de_cide to do so. Tbe darkest-colored countries could acquire this capa_bility within a year or two, the medium-colored ones nithin two to

50

six years and the lightest-colored ones within six to l0 years. Nationsthat have already tested nuclear explosives are shown in gray. Aster-isks are used to designate nations that are not parties to the Nonpro-liferation Treaiy. Although neither Israel nor South Africa has yetexploded a nuclear device, it is reported that they both now have the ca_

place it in any disadvantageous positioncompared *,ith the U.S.S.R. if it weredone on a temporary trial basis and theRussians u'ere called on to take similarunilateral action and to begin negotia_tions for a cutoff treaty. The U.S. mighttherefore consider whether it coutd id-vance the cause of curbing both the ver_tical and the horizontal pioliferation ofnuclear \\'eapons by initiating such uni_lateral action. If the initiative were care_f ully prepared in private through diplo-maric channels, it might lead to a rciultas successful as the unilateral cutback inthe production of lissionable materialfor weapons in 1964 and the unilateralcutoff of the production of biologicalagents for weapons in 1969. Such unilat-eral national action has the great meritof speed and timeliness in iti initiationand implementation.

. The.two superpowers agreed last yearin their Joint Statemenr of principles

pabilit5 of doing so. Libya is included as a po-tential nuclear-weapons state by virtue of its;pecial ties to Pakistan. The map is an updal-ed veriion of one published by the auflror inthe April 1975 issue of Scrp:irrnrc A\tERrcA\.

and Basic Guidelines for SubsequentNegotiations on the Limitation of

-Stra_

tegic Arms that they would pursue ..sig-nificant and substantial reductions inthe numbers of strategic offensive arms[a-nd] qualitative limitations on strategicoffensive arms, including restrictions-onthe development, testing and deploy-ment of new types of strategic offensivearms and on the modernization of ex-isting strategic offcnsive arms... It is ob-viously in their mutual interest to doso, not only as a means of containingthe nuclear-arms race and reducing thithreat of nuclear war but also as a possi_ble avenue for restraining the spread ofnuclear weapons to other couniries.

When the cutoff was first proposed byPresident Eisenhower in 1953, the situa_tion in the world was vastly differentfrom what it is now. The U.S.S.R. wasfar behind the U.S. in all areas of nucle-ar weaponry, and the danger of the pro-liferation of nuclear weapons was stillrather remote. Today there is a roughparity between the two superpowers,and the threat of the further spread ofnuclear weapons to additional coun_tries, with all the incalculable problemsthat it would present to the supirpowersand to the relative stability of the inter-national situation, is a very real danger.

There is no assurance that if the su-perpowers were able to agree on a banon the production of fissionable materi_al for weapons or other explosive nucle-ar devices, that act alone would preventthe proliferation of nuclear weaponsto additional countries. Nevertheless,a_ cutoff treaty could, particularly if itclosely followed a comprehensive testban, provide concrete evidence that thesuperpowers were determined to haltand reverse the nuclear-arms race. Itmight also create sufficient positivefeedback to facilitate other miasuresthat would halt both vertical and hori-zontal proliferation.

ly for peaceful purposes, there would beless fear that if the world does in factmove toward breeder reactors and plu-tonium recycling, it would lead to nucle-ar-weapons proliferation.

here is of course the ever presentr matter of the politics of the cutoff.

The difficulties of achieving agreementon the SALT II Treaty and the loomingthreat of the Senate's failure to give its

Apart from the major considerationsoutlined here there is an additional rea_son for proceeding with a cutoff. In spiteof the opposition to nuclear powerplants that has developed in receni yearsit seems fairly clear that the world willhave to rely on nuclear power as an im_portant and perhaps growing source ofenergy in the future. The fears of afew years ago of a shortage of urani-um for nuclear reactors, which seem tohave subsided for the moment, may verywell revive. The high-enriched uraniumstockpiled for weapons could providea source of low-enriched uranium forpower reactors. Every 1,000 kilogramsof weapons-grade uraniu- couid beconverted into some 30,000 kilogramsof nuclear fuel for reactors. This energysource would by itself help to postponethe advent of commercial breeder ieac_tors and the plutonium economy. Fur-thermore, if all fissionable material pro-duced in the future were to be used sole_

consent to ratification are so great thatthey create doubts for evcn the most op-timistic proponents of arms control. Thecurrent mood of the American publicand Congress verges on hostility towardarms-control measures. This antipathy,however, makes it all the -ore necei_sary to seek new ideas and openings thatcould keep the process going. Under themost pessimistic circumstances short ofwar it is almost inconceivable that thetwo superpowers would abandon theirefforts to halt the nuclear-arms race andrestrain the proliferation of nuclearweapons. Even during the ..cold war"the U.S. took imaginative initiativessuch as the Baruch plan in 1946 and the"Atoms for Peace" proposal in 1953.Any initiative in favor of the cutoffwould be much simpler and far less radi-cal than either of those initiatives.

The fact that the U.S.S.R. has in thepast opposed a halt in the production offissionable material for weapons pur-poses without a corresponding haft inthe production of nuclear weaponsshould not be regarded as an insupera-ble obstacle. In the case of almost everymultilateral arms-limitation agreementthe U.S.S.R. at first took a radical posi-tion and called for total prohibitions.When it became apparent that the over-whelming majority of states were op-posed to an all-or-nothing approach andconsidered half a loaf better than none,the U.S.S.R. has in almost all cases ac-cepted a partial solution, often alongthe lines urged by the U.S. This samepattern has been repeated in many as-pects of the SALT negotiations. Henceon the grounds of historical experienceas well as of logic there is reason to hopethat the U.S.S.R. would agree also to thecutoff as a first step toward further mea-sures of nuclear-arms limitation.

The recent initiative taken by Canadahas already received the support ofnearly all the Western and nonalignedcountrics. If the leaders of the U.S.would once again apply their minds tothe cutoff, the problem could be on theway.to solution. Apart from the earlyachid:vement of a Comprehensive TestBan Treaty, it is difficult to imagine amore promising new step than a treatybanning the production of fissionablematerial for nuclear weapons. Such aneffort could also do much to restore theeroding credibility of the U.S. commit-ment to nuclear-arms control and non-proliferation.

AUSTRAIIA

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