March 27, 1984

March 27, 1984 | Backgrounder on National Security and Defense

The Flawed Test Ban Treaty

(Archived document, may contain errors)

340 March 27, 1984 A FLAWED TEST BAN TREATY INTRODUCTION In 1974, the United States and the Soviet Union negotiated and signed the Threshold Test Ban Treaty (TTBT which limited underground nuclear testing to a maximum yield of 150 kilotons.

Although the Treaty has never been approved by the U.S. Senate the two countries pledged to observe the terms of the TTBT signing of the TTBT, and two years later, the Peaceful Nuclear Explosions Treaty, was heralded by many as the beginning of the process leading to the long sought-after comprehensive ban on all nuclear testing. However, Soviet violations of the terms of the TTBT, combined with the lack of any verification guarantees, have entering into international arms control agreements before securing ironclad verification requirements The caused the Treaty to become a symbol of the flawed premise of The TTBT bans underground nuclear tests for weapons that have explosive yields greater than the equivalent of 150,000 tons of TNT-over ten times the power of the bomb dropped on Hiroshima.

If nuclear testing were limited, the hope was that the development of Soviet nuclear weapons would be limited, thus increasing U.S security.

These hopes have floundered, as President Reagan's recent report to Congress on Soviet violations of arms control agree ments clearly showed. Soviet noncompliance with. TTBT, the Anti Ballistic Missile (ABM) Treaty, and the Strategic Arms Limitation Treaty (SALT) increases the possibility that Soviet nuclear weapons could overwhelm existing U.S. forces.

Even if effective verification procedures were accepted by Moscow, the Soviets have achieved military advantages that strongly suggest that ratification of the TTBT would be inimical to U.S. security interests. To redress the worsening strategic 2 balance, further testing is required to achieve a number of extremely Cmportant improvements in U.S. nuclear weapons tech nology. Testing at higher yields and the continued development of nuclear defensive systems are also required. The TTBT effec tively prevents any of these necessary measures, and thus reduces U.S. security.

THE SOVIET TESTING RECORD I I I Since the TTBT was negotiated, it has been criticized alike by arms control apologists and by arms control skeptics. Arms control enthusiasts regard the 150-kiloton testing limit as much too high. Skeptics feel that the Treaty would freeze the great Soviet advantage in high-yield warheads, hinder U.S. efforts to undo the harm done by the "assured destruction" doctrine of the McNamara era,l and limit the U.S. to weapons not optimal for at tacking hardened or protected military targets.

Skeptics also argue that the Treaty is basically unverifiable.

The reason: a factor of two uncertainty exists concerning the method for estimating the'yields of Soviet underground nuclear tests. Critics contend that, with current test measuring capa bilities, a test at 150 kilotons would occasionally appear on the measuring instruments to be 300 kilotons, and more important occasionally appear to be only 75 kilotons. Finally, the TTBT would prevent testing of nuclear weapons designed for the defen- sive purpose of attempting to minimize nonmilitary casualties and damage from a nuclear exchange.

When the first evidence of Soviet testing well above the TTBT limit came to light in 1976, the initial U.S. government response was to stop releasing reports of Soviet nuclear test yields to the public tific basis to cast doubt on the yield estimates themselves In 1977, the Carter White House ordered the intelligence community to adopt a new methodology that in effect cut estimates of these yields in half doubled the yields of their underground testing and again appeared to be in violation of the TTBT The next step was a search for some scien Within a year of this change, the Soviets nearly During this period there were press reports, since confirmed by the Reagan Administration of Soviet tests with estimated yields or central values, the middle of the range of estimates of possi ble yields) well above 150 kilotons responded by withholding the facts and making misleading statements The Carter Administration See infra p. 9 See. for example. Jack Anderson U.S. Can't Tell If Russia Cheats on Test Ban," Th Washington Post,

The Administration's position on the TTBT remains that the U.S. should not ratify the treaty unless the Soviets agree to improve verification procedures. The U.S meanwhile, continues to adhere to the 150-kiloton limit, despite Soviet rejection of any further negotiations on the subject.

THE TECHNIQUE OF VERIFICATION Determination of a Soviet treaty violation is based upon interpretations of signals received thousands of miles away from Senate Armed Services Committee, Preview Budget Briefing Fiscal Years 1981-1985 Five Year Defense Program (Washington, D.C U.S. Government Printing Office, 1980 p 37. Harold Agnew, op. cit.

Rudy Abramson Senators Press Reagan on Two Nuclear Pacts Los Angeles Times, May 26, 19

82. Other prominent individuals and newspapers soon followed suit and urged ratification. See for example: Theodore C. Sorenson Test Ban and Epitaphs New York Times, July 25, 1982; see also "Banning the Ban," The New Republic, August 16 and 23, 1982 Nuclear Steps to Take Now," The Christian Science Monitor, August 6, 1982 A Mistake on Nuclear Test-Ban Negotiations The Minneapolis Tribune, July 25, 1982; and "The Tail of the Snake The Boston Globe, July 23, 19

82. Prepared Statement before the Senate Foreign Relations Committee Wash ington, D.C ACDA, Mimeo, 1982 Mr. Rostow's concerns become ironic with his calling for the Treaty's ratification. 4 the Soviet test sites.7 distance through the ground can be distorted substantially. This distortion is known as "path bias.lI Since the seismic waves from Soviet tests pass through geologic formations very different from those for U.S. tests, there is no assured basis for comparison.

Any path bias assumption is at best an educated guess; there is no way of being confident that the estimate is accurate Seismic signals travelling such a long Seismic waves generated by different Soviet tests in the same area, however, would be subject to the same path bias, and thus can be compared to each other with great accuracy. This is significant because a pattern of Soviet testing at the same sites has developed that strongly suggests, in spite of the uncertainties inherent in U.S. estimation of Soviet yields, that the Soviets are in fact actually violating the TTBT. Most of the Soviet nuclear tests that appear to be over 150 kilotons occur in one area: the Shagan River test site in Eastern Kazakhstan in Central Asia.

Rather than directly challenge the Soviet Union, the Carter Administration decided in 1977 to introduce path bias assumptions into the calculations of Soviet test yields, thereby reducing their yield estimate8 (see chart on page 5). Tests that had previously appeared to U.S. specialists to be in the range of 300 kilotons-a TTBT violation-were I1correctedl1 by path bias and declared in'compliance with the TTBT In the words of one expert We [the U.S have normalized our criteria for detection in order to reconcile the seismic signals received to keep Soviet tests within the 150-kiloton limit.11g Within a year, the Soviets had begun testing at levels that again appeared to violate the TTBT by roughly a factor of two.

Because these tests took place at the same test site, there was no doubt that the test yields had increased in a way that could be compared to previous tests rected for path bias and yet, again, appeared to be nearly twice the 150-kiloton TTBT limit These tests had already been cor The Soviet tests after 1978 are about twice as powerful as the tests conducted between 1976 and 19

78. Thus, if the Soviet tests between 1976 and 1978 were. in the 150-kiloton range, those after 1978 must be 300 kilotons or more--clearly in violation of the 150-kiloton limit.

If the post-1978 tests were under the 150-kiloton limit the earlier tests must have been under 75 kilotons to account for the increased percentage. This would mean that the Soviet See "Soviet Violations of Arms Control Agreements ressional Record, May 19, 1983 pp. S7134-7139 rior to 1977, no path bias was assumed the TTBT in The Con Harold Agnew, op it 0 0 0 0 P 6 Union for almost three years was testing at less than half the negotiated testing limit. Given the Soviet record of stretching arms control agreements to their limits and beyond, the contention that they tested at such a low level for such an extended period strains credulity In fact, Soviet military requirements provide a great incen tive for the Treaty maximum or beyond seventies, the Soviet Union introduced a new series of improved intercontinental ballistic missiles (ICBMs including the SS-17 SS-18 Mod 4, and the SS-19 Mod 3.1 associated with these missile warheads strongly suggest that it would have been unlikely for the Soviets to deploy these weapons without testing well above 150 kilotons. The incentive for future Soviet testing above the Treaty limit is the development and deployment of a new generation of warheads designed specifically to destroy U.S.missile silos In the late The megaton range yields Although questions concerning compliance cannot be resolved completely with currently available technical data, informed and reasonable judgments can be made cates that Moscow continues to test at levels far above the TTBT limit but within the factor of two uncertainty the U.S. believes it can assess. U.S. estimates of Soviet yields already have been correctedll once for path bias. Thus the inescapable conclusion from a TTBT verification standpoint, is that the uncertainty factor on yield verification must approach four if the Soviets are to be judged in compliance. This serious technical uncertainty, combined Treaty, must call into serious question the desirability of its ratification by the U.S The pattern of testing indi I i with the Soviets' powerful military incentives to violate the i IMPROVING .TTBT VERIFICATION The fundamental problem with the TTBT, as with most arms control agreements, is verification. First, underground testing by its very nature precludes collecting the information about nuclear design and yield that could be obtained by observing the explosion. Second, the TTBT is the only modern arms control treaty that does not ban deliberate concealment that would impede verifi cation. Under the TTBT, it is perfectly legal to conceal every thing about a nuclear test and engage in deliberate deception.

For example, exploding a nuclear device in a cavity tends to reduce its seismic signal and makes the explosion and its yield appear smaller than they are No improvement in seismic detec tion would reduce significantly the margin of uncertainty regard- ing yields of underground nuclear explosions. The verification lo The Defense Department, Soviet Military Power 1983 (Washington, D.C Government Printing Office, 1983 pp. 17-18 7 problem lies not in recording the seismic signals but in inter preting what those signals mean It would not be possible to eliminate all the uncertainty about Soviet nuclear testing yields even if all U.S. verification proposals were accepted. Moscow could still cheat. But reduction of the current margin through cooperative verification procedures could reduce substantially the military significance of possible Soviet cheating under the TTBT achieved because the TTBT specifies exchanges of data following ratification. Yields of two past explosions in each designated geophysically distinct" (undefined in the Treaty) testing area would be exchanged. However, the Soviet Union could provide false yields if they were testing at above the 150-kiloton limit.

Thus, such yield information would change nothing. Data about certain elementary physical properties of the test sites would be a secondary part of this exchange even if assumed to be accurate, would be of little help unless the Soviets provided detail far beyond that specified in the Treaty. This is highly unlikely, given past and current Soviet attitudes It has been suggested that adequate verification might be Knowledge of these properties The data exchange mandated by the TTBT could even worsen matters because it would create a legitimized channel for Soviet misinformation. There would be no verification that the data concerning calibration shots were correct.ll The yield data the Soviets provide in two tests could be false and intended to give the impression that all Soviet tests were of a lower yield.

What kind of agreement would improve yield estimation so that compliance with the TTBT could be verified? Clearly, it would be necessary to obtain independently verified data that allowed less ambiguous yield estimates. The specific U.S. pro posal is for a direct yield measurement obtained by inserting a cable down the emplacement hole into the vicinity of the ex plosion. The cable would measure the speed with which the explo sion energy travels out through the ground, allowing much more accurate yield estimates. U.S. personnel would be required at Soviet test sites, and Soviets would monitor U.S. tests. Moscow however, has rejected this approach SOVIET COMPLI~CE WITH ARMS CONTROL AGREEMENTS With adequate verification.of the TTBT in doubt, the record of Soviet treaty noncompliance becomes even more relevant no longer possible to doubt seriously Soviet violation and circum vention of existing arms control treaties. Said President Reagan It is l1 See Judith Miller Experts Split on Flaws in Pacts Limiting Nuclear Tests,"

New York Times, July 26, 1982. 8 III am sorry to say that there has been increasingly serious ground for questioning their compliance with arms control agreements that have already been signed and that we both have pledged to uphold."l2 Secretary of State George Shultz has characterized MOSCOW'S behavior as a If continuing practice of stretching a series of treaties to the brink of violation and beyond.Ifl3 Nearly every agreement in this area has produced credible allegations of Soyiet noncom pliance.

When the Soviet Union apparently decided to conduct nuclear tests at yields that violated the TTBT, it did so after more than a decade of violations of the 1963 Limited Test Ban Treaty (LTBT).

After an initial announcement by the Johnson Administration.of a technical violationIf of the Treaty in 1964, the U.S. government neither insisted on Soviet compliance nor made any further an nouncements of additional LTBT violations. The Carter Administra tion refused to release any information concerning the Soviet venting of radioactive nuclear debris across its borders and even denied that such events violated the LTBT: "There have been vent ing cases in which radioactive nucleii have been detected outside the Soviet Union again these are not clear violations are matters of stretching the limits of the agreement."14 They The U.S. government, as early as the mid-l960s, signaled to the Soviet Union that it would not insist on strict Soviet compli ance with arms control agreements. In addition, the Soviet Union saw the U.S. government rationalize a host of Soviet activities between 1973 and 1976 that either violated SALT I or circumvented its essential limitations. It would be understandable if the Kremlin concluded that the U.S. government would do nothing against Soviet testing above 150 kilotons. And indeed, the only U.S. responses were ineffectual dkmarches followed by predictable Soviet denials.

The Soviets soon may be able to deploy a new ICBM, contrary to SALT I1 Treaty limitations. It would have an advanced warhead developed in violation of the TTBT, and would be defended by anti-ballistic missiles, in direct contradiction of the ABM Treaty.

The lack of an American response to previous Soviet violations of arms control agreements enhances the possibility of this scenario.

THE TTBT AND U.S. SECURITY Even if agreement could be reached assuring effective veri fication of the TTBT, serious questions arise as to the actual l2 l3 Text of Remarks by the President to the Los Angeles World Affairs Council Washington, D.C The White House, March 31, 1983 p. 2 U.S.-Soviet Relations in the Context of U.S. Foreign Policy Statement before the Senate Foreign Relations Committee (Washington: State Depart ment Mimeo, June 15, 1983), p. 8.

Former Secretary of Defense Harold Brown, cited in Senate Armed Services Committee, op. cit l4 9 utility of limiting testing in the manner called for by the Treaty.

Donald Kerr, Director of the Los Alamos Laboratory, has pointed out that Ifnuclear tests are essential for determining the proper functioning of nuclear explosives; calculations do not suffice and there is no way to experimentally simulate the performance of a nuclear design I1 Because the U.S. has limited itself to very small missile systems, one objective of nuclear testing is to increase yield-to weight ratios-the amount of nuclear explosive yields obtained from any given weight. Nuclear weapons are also frequently removed at random from the existing stockpile and tested to prove that they will have a given yield ducted about 40 such tests.

Over the years the U.S. has con In addition, the U.S. tests nuclear devices to correct prob- lems that develop in weapons that have previously been placed in the stockpile. By 1978, there had been a dozen instances in which weapons revired a nuclear test to repair a problem. If a problem with a nuclear weapon required a test over 150 kilotons, it could not be repaired under the TTBT.

The TTBT also limits development of new weapons types. New designs are constrained by the Treaty.'s test ceiling, and options for developing systems exceeding the 150-kiloton limitation must utilize existing designs to insure Treaty compliance.

The negative impact on U.S. security is even greater when probable Soviet TTBT violations are taken into account. Since 1978 the Soviets have conducted 15 nuclear tests that appear on U.S. instruments to have yields substantially above the 150-kiloton TTBT ceiling. The argument that no Soviet violations have occurred is technically plausible in the sense that one cannot prove it in a purely scientific.manner, but it is extremely unlikely in a practical sense when other factors are taken into account.

The limitations the TTBT places on nuclear testing must also be viewed in the context of historical nuclear strategies. The introduction of the mutual assured destruction doctrine in the early 1960 resulted in the termination of most major weapons systems other than the Minuteman and Polaris programs. The devel opment of small missile systems carrying small warheads, such as l5 Dr. Donald Kerr, former Acting Assistant Secretary for Defense Programs Department of Energy, current Director of Los Alamos Laboratory, testimony before the House Armed Services Committee Effects of a Comprehensive Test Ban on U.S. National Security Interests Washington, D.C Govern ment Printing Office, 1978 p. 5.

A detailed explanation of MAD may be found in the "Statement of the Secre tary of Defense Robert S. McNamara before the Senate Armed Services Com mittee on the Fiscal Years 1969-73 Defense Program and 1969 Defense Budget Washington, D.C Government Printing Office, 1968 pp. 41-69 l6 10 the Minuteman I11 and the Poseidon, produced a combination that does not have the yield and accuracy capability to destroy hardened military targets. This shortcoming has been exacerbated by the deployment of Soviet ICBMs with the ability to destroy hardened U.S. targets.

To counter this new threat to U.S. deterrence and nuclear stability, the Accelerated Test Program was begun in the U.S during the 1970s. A primary objective of this program was to seek out and develop new options for higher yield weapons to destroy hardened Soviet targets. Testing of any of these new weapons would be precluded under the TTBT if their yields in creased by a substantial amount.

Supporters of the TTBT have argued that testing new designs at the higher yields needed is no longer necessary because nuclear weapons development is at a technological plateau and further design improvements cannot be achieved. On the contrary, Robert Woodward, Associate Director of Nuclear Design, and W. F. Scanlon Deputy Director of Military Applications at the Lawrence Livermore National Laboratory, point out that the so-called Ilplateau" is actually caused by the Ilimposed limits of the TTBT rather than the lack of anything technically new to be done.1117 As a result of observing TTBT limitations, the U.S. has been forced to use older, less advanced designs for the MX and Trident I1 warheads because their tests were allowed at full yield only before the signing of the TTBT. There is a substantial risk in using these older plans. dramatically the performance, of nuclear weapons systems, rendering the older plans relatively obsolete. The warheads for the MX Trident 11, Mark 12A, the new bomb carried on the B-52, and the future B1-B bomber cannot be proof tested at full yield in their final deployed form under the TTBT. The MX, Trident 11, and cruise missiles all have "options under research and development upon which nuclear testing has not been completed, and the U.S would not certify them and place them into the strategic'stockpile without having completed that nuclear testing.I1l8 Strategic uncertainties concerning their performance Very slight design changes often can improve deterrence systems have never been previously deployed with such An additional problem facing the'U.S. is the shortage of special nuclear materials, including plutonium and Uranium-235 which comprise the basic building blocks of nuclear weapons.lg l7 l8 Letter to the Editor, The Washington Post, August 10, 1983.

Admiral R. R. Monroe, Director of the Defense Nuclear Agency, testifying before the House Armed Services Committee Current Negotiations on the Comprehensive Test Ban Treaty Washington, D.C Government Printing Office, 1978 p. 104.

See Arnold Kramish America's Plutonium Predicament Strategic Review Summer 1982, p. 48 l9 11 This shortage might be averted through the development and deploy ment of higher kiloton nuclear warheads that use lower levels of special material to achieve their design yields. However, TTBT limits prohibit the testing, and hence the development and deploy ment, of these weapons with yields of more than a few hundred kilotons--precisely the type most needed today. The problem of critical nuclear material shortages, then, is exacerbated by the TTBT, thereby limiting the U.S. ability to meet the growing Soviet threat.

Besides requiring the use of older and less efficient designs for multibillion dollar strategic weapons, the TTBT limits the response to future Soviet military hardening programs. Any such Soviet fortifications will require the U.S. to deploy megaton and multimegaton yield weapons to maintain a credible deterrent.20 It becomes imperative to test higher yield weapons systems that can penetrate these hardened targets because "it is not possible to always accomplish the same objective with greater accuracy of delivery.II2l Yet there is no viable option of testing in this yield range.

Improved air defenses in the Soviet Union, not limited by any treaty,22 also contribute to the need for larger testing yields. Bombers and cruise missiles must travel longer distances to overcome these air defenses, reducing the accuracy of their payloads. This in turn requires an increased yield from the weapons carried in order to offset the decreased accuracy if a. target is to be effectively destroyed combination of new defense and hardened targets, the development of higher yield weapons, is precluded under the TTBT The best response to this The ABM Treaty and the TTBT limits also essentially preclude the development of advanced U.S. defensive weapons, such as the ABM program and the so-called X-ray laser.23 .Yet Soviet.ABM related.activities--research, testing, and radar deployment create a real threat of violation or "breakout" from the ABM 20 21 22 23 The yields, for example, for the Poseidon and Minuteman I11 are only .04 megaton and .17 (or .335) megaton, respectively weapons are in the mega'ton or multimegaton yield range. See Mark B Schneider SALT and the Strategic Balance Strategic Review, Fall 1974 p. 42; and Colin S. Gray Of Bargaining Chips and Building Blocks,"

International Journal, Spring 1973, p. 287 Woodruff and Scanlin, ERDA Funding and Management Alternatives for ERDA Military Applications," p. 2 Air defense systems against air-breathing weapons, such as the manned bomber and cruise missile, are not covered under the ABM Treaty.

The largest underground U.S. nuclear test'was devoted to the development of an ABM warhead for the Spartan ABM Nuclear Technology in Support of Our Strategic Options Air University Review, November 1.976, pp. 33 Comparable Soviet See Major General Edward B..Giller, 12 Treaty. There are four references to this possibility in the bi partisan Scowcroft Commission Report on Strategic Forces.24 By violating both treaties, the Soviets may be able to deploy effec tive strategic defensive weapons, while the U.S., limited to exploratory research and development, will lack this capability.

One option for meeting this threat would be for the U.S. to develop new strategic warheads, putting a great premium on nuclear testing above 150 kilotons.

CONCLUSION Soviets responded by increasing their testing yields to over 300 kilotons. The Soviet Union apparently had some tests as high as 350-400 kilotons.

Testing at these yields enables the Soviet Union to develop new and improved nuclear weapons systems for its seemingly unending series of new missiles. At the same time, the U.S. limits itself to testing at 150 kilotons and cannot develop weapons suitable for use on its MX, Trident 11, or Midgetman ICBM unless it adapts existing, older designs. The only other available option entails the serious risk that major new strategic systems will be deployed with warheads that will not deliver their expected yield because of the lack of appropriate testing.

Treaties that favor the USSR, the TTBT gives Moscow a significant military advantage. This undoubtedly will grow with time. The Soviets have, in effect, boosted the yields at which they test.

The higher the yields tested by the Soviets, the more the U.S revises its methodology to legitimize these tests. The Soviet Union has tested and will continue to test at slightly more than twice the maximum allowable yield calculated by the U.S. at any given time. Thus, if the U.S. takes action in the future to legi timize Soviet tests now estimated at 300 kilotons or more, the Soviets will be able to test at 600 kilotons by any procedure 'apparently acceptable to Moscow. The Soviets have rejected all negotiations concerning improved verification.

The United States, moreover, has sound national security reasons for not ratifying the TTBT. There is substantial evidence that the Soviet Union is cheating. The U.S. has clear military requirements for developing and testing weapons above 150 kilotons.

If the current situation persists-in which the Soviets are probably testing at two to three times the Treaty limit--the U.S. will con tinue to fall behind the Soviet Union in strategic military power When the U.S. revised its testing methodology in 1977, the When combined with the features of the SALT I and SALT I1 The TTBT is not now verifiable and cannot be made verifiable Brian Green Policy Analyst 24 Report of the President's Commission on Strategic Forces, April 1983, Brent Scowcroft, Chairman, pp 10, 12.

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