NIE56
INTELLIGENCE ESTIMATE
6
Impacthreshold Test Ban Treaty on Soviet Military Programs
mini (Him
OF CENTRAL INTELLIGENCE
Ccnawrro' im bf itm UNITED STATES INTELLIGENCE BOARf
Al iixfsatrd omW6
Pagetopy
fOlltifASI BATE UK Till
Tnr irrnrr
the following rn'olfigrfnce organizations participated in tho preparation of thit estimate!
Thentelligence Agency ond ihe intelligence organization!heof Stole, Detente, ihe NSA, and AEC
Concurring:
Mr. Huntington D. Sheldon, lor Deputy DirectorCentral Intelligence
Mr.ughei, The Director ol Intelligence and Bo search, Department ol Stoto
Moj. Gen. Robert Taylor, 3d, for Director, Defeme Intelligence Agency
Dr. Louii W.dello. for Director ot the Notional Security Agency
Mr.rown,uiitant General Monoger, Atomic Energy Commiuion
Abstaining:
hop oreRpr -
Mr. William O. Cregor, lor Aiilitant Director, Federal Bureau of Investigation, tho tubject being outitde ol hit juradictton.
1
TABIC OF
THE
FOREWORD
CONCLUSIONS
I. CURRENT SOVIET NUCLEAR WEAPONS
A. Technology Applicable lo Programs Other Than 4
II. Tccluiology Applicable lo ABM Programs 5
TABLEOVIET HICH ALTITUDE 6
IL IMPACTHRESHOLD TEST BAN TREATY ON SOVIET
MILITARY PROGRAMS 7
on Nuclear Testing 7
on Military Programs Other Than 8
on ABM 9
ILL US DETECTION 9
Capabilities of the10
ol Intelligence Sources
Ciolation11
IV. THE POSSIBILITY OF SOVIET COVERT VIOLATION11
occur.t
the impacthreshold test ban treaty on soviet military programs
the problem
To estimate the impacthreshold Test Ban Treaty on Soviet military programs, with particular emphasis on its impact on Soviet ABM activities; to discuss the capabilities of US intelligence to monitorest ban; and lo evaluate Soviet capabilities for covcitlyit.
foreword
The Threshold Test Ban Treaty considered in this estimate isin line with proposals under discussion in the US and abroad, but it docs notpecific proposed treaty. Wc assumeof the terms of the Partial Test Ban Treaty now in effect, which prohibits testing of nuclear devices in the atmosphere; beyond its limits, including outer space; underwater (including bothwaters and the highr in any other environment if such explosion causes radioactive debris to be present outside the territorial limits of the state under whoser control such explosion is conducted. The Threshold Treaty considered in this estimate would add to the restrictions of the currentrohibition of anynuclear testeismic disturbance5 on the Cutcnberg-Richtcr scale. It is assumed that treaty language willethod byean magnitude for any particular event will be established, thus avoiding international disputes about the magnitude of reported events. It imposes no limitations on themedium in which the tests take place, or on the degree of decoupling employed. It provides no on-site inspection and no sanc-
I
lions. Kncli participating nation will haveecide for itself whether any given seismic event of magnitude greater5 was causeduclear detonation andreaty violation.
CONCLUSIONS
believe that for most of the Soviet military developmentwhich we can foresee over the next fewhrcslwldTreaty would impose no greater restrictions than those alreadyby tlie Partial Test Ban. However, the relationship betweenof underground explosions and tlie resulting seismic readingsat best, and can be greatly altered by decoupling.might dicrcforc still testide range of yields,how far they were willing lo risk violating the treaty and tocost and effort of decoupling. Practically speaking, wethey could develop weapons yielding Q
by scaling up from lower yield testsouldair chance of nol producing seismic readings They mightdevelop TN weapons with yieldsjj^ by expensive decoupling methods. )
respect to ABM weapons, we think there is about an even
chance that the Soviets have already
^exoatmosphcric ABM warhead yiciouig ]
If they have not already donehreshold Treaty would nbt, in our view, makeevelopment impossible, as we believe existing Soviet weapon technology would support it either without further testing, or with tests lhat wouldeasonable chance of not exceeding the threshold.
believehreshold Treaty would imposebeyond those of tlie Partial Test Ban, orjly forwhich might need new warheads
I If tlie development of such weapons had a" sufficiently high prionty the Soviets might conduct tests virtually certain to violate the treaty, in the belief that the violation could not be proved against them. As few as one or two suchear could be of significant aid to their military programs. )
US Atomic Energy Detection System (AEDS) wnuMcertainly detect all seismic events in the USSRr greater. Perhaps with helpcould probably discriminate between expnnroro amrin most jyuTs of the USSR, but there would still beearspevjitniy the Kamcliatka-Kurilescould not be so identified. Such events would representtreaty violations, but it would be extremely unlikely thatcould with certainty either confirm or deny that ahad in fact occurred. )
a seismic event5 was identified as an explosion,almost certainly be nuclear in origin. Thus this evidence,with what might be available from intelligence sources,be sufficient, exceptew cases, to determine to theof the US government whether or not the explosion wasin origin. Evidence sufficient toorld forum thatwas nudcar could almost certainly be derived onlyinspection, which is not permitted by the Thresholdconsideration.
DISCUSSION
L CURRENT SOVIET NUCIEAR WEAPONS TECHNOLOGY
L The past decade ofopV.uiicatcd Soviet testing of nuclear dc-vicci and weapons has included9i intensive test* in
nd two years of testing underground since tbe Partial Testwas signed inn evaluation of the cfFccts ol aBan Treaty on Soviet military programs must starteview ofnuclear technology developed through these tests and its relation toprograms.
A. Technology Applicable to Programs Other Than ABM
eapon* Development. The Sovietsamily o( thermonuclear (TN) weapons responsive to tlie present needs of dicir strategic attack and general purpose forces. Soviet Long TUngc Aviation and the Rocket Forcesarge number of older TN weapons in the low megaton range based on the results of die tests conducted8 and earlier. Weapons, based on1 and
series probably began to enter siocVpilend are nowin significant quantities, and will continue to be produced in orderolder weapons still In the strategic attack forces stockpile. Thesogenerally represent significant improvements over the entireand probably include some high yield (ovei tea MT) TNdelivery by both aircraft andarheadfor thes estimated to be now availableesult tu amtests.
3 The Soviets hadSariety of relatively Urgeweapons in thewhich arc probably soil in stock-
pile in large numbers lor taction BBS and rocket forces, for tactical aviation, lor general purpose uses by the Soviet navy, and for SAM foices.esult ofests the Sovie" were able to develop fusion weapons in the
I Most ot the newer
fission weapons entering the Soviet stockpile inlan lew years are proliably these unproved low-yield weapons.
riorartial Test Ban Treaty the Soviets had largely fulfilled thou; baiic requirements lor multimegaton TN weapons and for fission weapons. They may stillequirement lor TN warlicarls In the submegatoo and low megatonor thehis rcquiremenl can bo fulfilled under tlie Partial Test Dan, and probably would be fulfilled before the Soviets accededhreshold Treaty. Undo the Partial Test Ban, the Soviets have conducted tests yielding upT. Some of the but] yielding aroundT and higher
wcrc probably directed toward development of TN waipons. Several tests yieldingT or less liavc been defected, especially during the past year, these could luvc been oriented lowud development of eitltcr Baton or TN weapons. Some weapons bated on the underground tests- last two years will probably start entering stockpile next year, and will be available (or system* beingover the ncxi several years.
5esting. Our analysis ol Soviet tests provides very littleon Soviet programs to enhance the kill potential of nuclear weapons, or on (he state ol Soviet knowledge of the various Icul effects of nuclearost of the thermonuclear tests were held at Novaya Zcmlya, where Uic Soviets were probably able to instrument only for the basic diagnostic informationfo* development of TN weapons. Most of the Soviet fission devices were tested at Semipa'itinsk; we know little about the mctlsods of testing there or the kinds of effects instrumentation employed.
he Soviets have conducted extensive tests of the efJccts of nuclear bursts on military equipment and structures. Although we cannot say how'imich the Soviets may have learned about kill cflccts from their tests, they have dearly bid ample opportunity to discover <li- same important nuclear effects whidi wc have discovered.
nalysis of Sane! publications and classified manuals shows that Ihe Soviets have acquired effects data of sufBdent scope and quality on air, surface,and underground bunts to be adequate for planning and executing most military operations. Undassuied articles show that they arc aware of theradiation effects on electronic equipmentlthough we have no knowledge of Ihe extent to which they may have explored these efforts, wc do have evidence that they ire aware of the vulnerability of US missile guidance systems to them. The Soviets have also shown that they understand thepulse (EMP) phenomena produced by nuclear explosions, and they may haveumber of low-yield surface tests to measure die EMP effect on military systems and communications equipment. Although the Soviets arc probably aware of the EMP vulnerability of ICBMs and silos, it is doubtful thai they have conducted tests of the surface EMI* effects of high yield weapons.
S. Considering the foregoing, we think tlte primary effect of the present Partial Test Ban on Soviet weapons programs has been to prevent complete systems testing and effects testing In the atmosphere or space. Nevertheless, the Soviets can obtain some significant data on these effects by simulating ntmospheric and space environments In underground tests.
echnology Applicable to ABM Programs
igh-Altitude Tests. Duringeries, the Sovietsumber of high altitude nuclear tests, near Sary Shagan. (Sec
JOP SEGRFf-
OVIET HICK ALT!TOOK TESTS
Joe Ko.
ten
(KT)
(KM)
1
Vertical Shot
1
1
Sliot
Motile) #
1
2
2
2
testsoviet interest in assessing the capability of an ABM system to discriminate and track two or more targets approaching successively on nearly identical trajectories, bothadar blackout environment andormal atmosphere-2 events appear to have been conducted for the primary purpose of studying the effects on radar systems of blackouts created by high yield precursor bursts or by detonation of the interceptor's own ABM warheads. Data relating to certain long range effects, such as EMP and THEE, may also have been collected. It is unlikely, however, dial the tests involved devices which had enhanced radiation outputr that the Soviets were testing for the vulnerability of re-entry vehicles (RVs) to shock produced by surfaco absorption of loways.'
luiractcrisiics of Certain Nuclear Weapons. Another portion of thetest scries involved the detonationroup of TN weapons in therange These weapons showed certain characteristics suggesting tliata new Soviet weapons design. One recent attempt to constructmodel exlubiting these characteristics ledesign thatanay output. We think it likely that the Sovietsthe importance ofay effects for CKoatmosphcric ABMcould adaptesign accordingly. If such is the case, thecouldeapon that wouldays I]
II. ABM Deployment. For several years the Soviets have been constructing what wo believe arc ABM defenses.1 The missile most likely to be used in an
oway output is One ofilo-eloction votuay energy can be enhanced, at (lie cipeiue of otl>sr (Recti, byoViign of tlie weipoo.y energyev it coniitieied medium energy,ev Is high energy. Ajienergyev it oftenay.
'See, "Soviet Strategic Air and MutileBond footnote! thereto.
TOP SCCItLT
IS
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enuNiioiiiliciic role in such defenses ii the Galoshalash-typc. Givendifficulties of identifying lethal warlicadsloud ofoutside the atmosplscce. it is desirable that an eioatmosphcricemploy weapons with asill radius as feasible. This in turna nuclear warhead with improved kill capabilities, one waymight be throughays. One ofp of weapons describedpreceding paragraph appears highly suitable for use with the Calo*iihave no evidence whatsoever thai (his or any other of tha group ofnuclear weapons is the Galosh warhead, not indeed con we_bc suregroup of new nudear weaponsNeverthe-
less, the apparent deployment of Lnow lyrpni employing em-atmospheric interceptors argues that the Sovietsaiheadarge kill radius, whatever mechanism may he used to achieve it.
It. Theions in the preceding paragraphs lead us to believe tint the chances arc about even that die Sovietsevdoned an exoatmosphcric ABM
even though wc think that
they dtViloTI completo system in lOol-lOui li is of course desirable to test ABM warheads In their actual environment, but it ur possible byfrom laboratory and underground test data to calculate the eflccts of specific waxheads on various objects at various altitudes.
IMPACTHRESHOLD TEST BAN TREATY ON SOVIET MILITARY PROGRAMS
limitations on Nuclear Testing
egree of Hiik Accepted. Because of variations ia geological structure aodie propagation paths of seismicuclear explosions o; the tame yield may produce quite diflerent seismic readings. Experimental evidence based on US tests and measurements indicates thai the seismic magnitudeuclear test of known yield andiven medium may vary by up tonits on the Culenberg-Riditer scale. As SO percent of (lie cases fall above and SO peiceai below the averagehot intended toeading5 on thai scale would0 percent chance of exceeding thatountry desiringercent assurance of not exceeding5 limit would be limited lo tests of about one-half the yield it might test with only SO percent assurance.
H Testing Medium. Most detected Soviet underground tests have taken place in granite. JO
SCCRCT
r i
ould be possible, without violating the Threshold Treaty, to test in dry alluvium devices of larger yield than those which could be tested in granite.
Wc believe that the Soviets have ad little experience in testing underground in dry alluvium at yields above the low kiloton range. The USSR probably has alluvial deposits of sufficient deptlt, but we do not, know whether lhe deposits are dry toepth as would permit testing
Decoupling. It is possible that the Soviets would resort totechnique in which die nuclear explosion takes placearge cavern, tltereby reducing the seismic disturbance. Decoupling at lower yields appears feasible, but io decouple larger yieldshat they can be tested within5 be com ci increaifngly expensive and difficult. It lias been estimated thativen seismic tlueshold one might test witheviceield up to as much asimes greater than could be tested withoutoupling. But thisighly theoretical and obviously very uncertain estimate.ractical matter, it seems to us likely on the basis of present knowledge that seismic eflects from an explosion on the ordermost of tlie time, be degraded through decoupling to5 reading,ery large and costly cavity would be required.
The Soviets could probably scale up from the devices tl>cy tested and build, with reasonable confidence, weapons having yields four or five times as great asest devices. Thus, we think that, pioviding they accepted in some0hance of exceeding the thrcslwld. the Soviets could develop weaponsConceivably they might develop weapons withy utilizing expensive decoupling methods. *
B. Impoct on Military Programs Oilier than ABM
IS. It follows from what lias been said abovehreshold Treaty would not seriously hamper Soviet development of small yield tactical weapons, low yield testing for special effects (enhanced or suppressed radiation for tacticalr acquisition of data on the vulnerability of components. Underreaty, though with some risk of violating it, the Soviets could also probably,
develop new or follow-on TN warheads with yields
for their small-silo missile systems, as well as lor newutue jy*.cmi.believe that for the tests needed to develop an entirely new warhead withSoviets would be forced either to resort to expen-
couplinjj. or,kcly, toreater thanercent chanceest would5 seismic reading. Full-scale tests of high yieldor of silo hardness against nuclear weapons cannot be conducted under either the Threshold Treaty or the Partial Test Ban.
Tlic Threshold
s difficult even under the Partial Test Dan to conduct the teststo developwarheadsreaty would add to these dullevltics.
technology would support iL eitlicr without further testing or with tests that wouldeasonable diancc of not eaceediog the threshold. The Soviets coulday lethality data applying toarhead from underground testing without violating the Treaty. We believe also that inests the Soviets acquired enough data on radar blackout dTects to permit them lo develop and deploy this weapon system. Although llie Soviets would almost certainlyequirementull-yield eroalmosphcric lest of the system and for tests to acquire additional blackout data, this is already prohibited under the Partial Test Ban.
behove the Soviets have not developed an ABM warhead
They migliteed tar
In this event; we Deuevccaty would ootoafe-
ing factor as long as the prospective warheads were in the submegaton range. For the devdopmcntew ABM warhead of this type In (lie multimegalon range Use Threshold Treaty wouldignificant limitation over the present
treaty.
III. US DETECTION CAPABILITIES
Igh
till!
ability of the US tohtcsliold Ticaty and to detectinvolves establishmenteismic event has taken place and ismagnitude, identification of such an event as natural or explosive Inidentification of an underground explosion as nuclear or conventionaliflcrcnt, but tdated, problem is that oforld for
SCCRCT-
tcncr
r
esort to such activity s0 far as practicable if they itlempledwe do not believe, they would be completely successful in
C.iolalion
i (a
Wc believe that in
tns
. auu. umwimonstratedorld lorum only1 un'lcr an? form of contemplated ThresMd
[
IHE POSSIBILITY OF SOVIET COVERT VIOLATION
e have estimated above that the Soviets can meet most of theirrefundments for weapons development without violating aIf they foresaw testing requirements for military programs thatconsistent eolation, they probably would not sign the treaty in theWc also believe theyot accede to the treaty unless theywould be relat.vcly advantageous to them, or at least notllicy had enteredreaty, the Soviets probably would feel thatto be gained from frequent violation would not be worth theto their international position, providing these violations were
t is dear, however, that the Soviets could gain significant advantages in weapons development from one or twoear which exceeded tlw threshold
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