CTBT Ratification: Pros and Cons

February 1999


Cato Policy Analysis No. 330

January 15, 1999



The Comprehensive Test Ban Treaty

The Costs Outweigh the Benefits


by Kathleen C. Bailey

Kathleen C. Bailey is an author and defense analyst.
Executive Summary
The Comprehensive Test Ban Treaty (CTBT) is now before the U.S. Senate for its advice and consent. The treaty bans all explosive testing of nuclear weapons.
Advocates of the CTBT make several arguments in support of the treaty. The reasons reduce to two points: the ban will constrain the modernization and development of nuclear weapons by the nations that already possess them, and it will help prevent the spread of nuclear weapons to additional nations. Both objectives are set out in the CTBT's preamble.
Opponents of the CTBT are most concerned about one issue: in the absence of nuclear testing, U.S. nuclear weapons can be neither as safe nor as reliable as they should be. Those deficiencies will diminish the effectiveness of the U.S. nuclear deterrent. While the treaty will constrain the United States from modernizing and developing weapons, it will be possible for other nations to cheat with little or no risk of being caught because the CTBT cannot be verified.
To resolve safety and reliability questions, the Clinton administration has developed the U.S. Stockpile Stewardship Program (SSP). The SSP is intended to improve knowledge about nuclear weapons to such an extent that it will be possible to fix problems and design new weapons without nuclear testing. The SSP is extremely expensive and technologically very risky.
Furthermore, it is unclear whether the SSP will accomplish its goal of attracting, training, and retaining scientists and engineers capable of fixing future problems with current weapons and designing new weapons.
Text of Policy Analysis No. 330 (PDF, 31 pgs, 124 Kb)
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Facing Reality

A Test Ban Will Benefit U.S. and International Security:


A Reply to Kathleen Bailey


By Christopher Paine, Senior Researcher,

NRDC Nuclear Program

The Cato Institute's new Policy Analysis seeks to weigh the costs and benefits of the Comprehensive Test Ban Treaty, and finds that the former outweigh the latter. However, this conclusion is reached through the application of sweeping and largely unsubstantiated generalizations about such complex matters as verification capabilities, the role of global norms in influencing the behavior of nation states, the role of nuclear explosive testing in maintaining U.S. weapons reliability and safety, and the role of nuclear explosive tests in the weapon development programs of prospective proliferant states. Moreover, omitted from the analysis is any consideration of the consequences for U.S. and international security that would likely ensue if the United States were now to resume nuclear explosive testing, as suggested by the paper.
In the analysis that follows, Dr. Bailey's contentions are highlighted in italics, followed by my response.
(The cover page for this report, "Facing Reality," is saved as: http://www.clw.org/coalition/nrdc0299.htm)
Opponents of the CTBT are most concerned about one issue: in the absence of nuclear testing, U.S. nuclear weapons can be neither as safe nor as reliable as they should be. Those deficiencies will diminish the effectiveness of the U.S. nuclear deterrent. (Executive Summary)
This formulation begs a host of questions which are not answered in the report, such as "how safe is safe enough," and "how 'reliable' does a weapon have to be to constitute an effective deterrent?" Moreover, the implied relationship between nuclear deterrent reliability in the statistical sense and a successful underground nuclear test does not exist. During the Cold War, neither weapons nor delivery systems were ever tested sufficiently to provide a valid indicator of their "effectiveness" in war. It is even more unlikely that the United States would do so now, even if afforded the opportunity to resume testing.
In agreeing to the extension of the original 9-month test moratorium established by the Hatfield-Exon-Mitchell Amendment, the Joint Chiefs of Staff reviewed the option of conducting an additional 15 tests over four years for the purpose of incorporating improved plutonium dispersal safety in 400 W-88 SLBM warheads and fire-resistant pits in two weapon types delivered by aircraft. These upgrades were rejected by DoD, the Navy, and the Air Force as not constituting cost effective investments in safety, especially in view of post Cold War changes in storage and alert procedures that reduced the likelihood of the very scenarios the proposed upgrades were designed to address.
While the treaty will constrain the United States from modernizing and developing weapons, it will be possible for other nations to cheat with little or no risk of being caught because the CTBT cannot be verified. (Executive Summary)
In reality, because of the depth and breadth of the Stockpile Stewardship Program, and the sheer amount of resources being devoted to it, the United States is better positioned than any other weapon states to "modernize" its weapons without resort to nuclear test explosions, and indeed, it is already doing so.
Moreover, while some amount of cheating at low yields is "possible" under a CTBT, as explained in detail below, most scenarios can hardly be considered probable, and it is utterly preposterous to suggest that such activity runs "no risk" of detection by the CTBT monitoring regime, or by U.S. unilateral monitoring capabilities, the intelligence capabilities of friendly states, and the world scientific community, whose seismic monitoring capabilities exceed that of the CTB's International Monitoring System in many areas of the globe.
Equally preposterous is the implication that nameless "other nations" would be likely to achieve technical results through clandestine tests that would somehow nullify America's enormous advantages in resources and technology and the knowledge that comes from having conducted over 1000 nuclear test explosions.
The organization will oversee the treaty's verification regime, called the International Monitoring System (IMS), and an International Data Center. (Introduction, p.2)
Actually, the treaty's "verification regime consists of the IMS and two other components ­ On-site Inspections and Confidence Building Measures. The paper does not mention or assess the contributions of these elements.
Because the CTBT is likely to have a profound impact on the reliability and future safety of the U.S. nuclear deterrent, the treaty's ratification is contentious. (p.2)
In reality, the CTBT is contentious because it (a) tends to downgrade the importance of nuclear weapons, and hence the role of the U.S. nuclear weapons establishment, in U.S. foreign and security policy, and (b) it severely constrains the development of new types of nuclear weapons and limits the ways in which nuclear weapons can be adapted or redesigned for changing military missions. As a purely technical matter, it is certainly possible, and if good judgment and managerial discipline prevail, it is indeed likely that a CTBT will have either a positive or no impact on weapons safety, and only a modest or no negative effect on confidence in enduring stockpile performance. A detailed explanation of why this is true is provided later in this critique.
Weapon Modernization
Constraining modernization is risky because it seriously degrades the ability of the United States to tailor its arsenal to emerging or as yet unknown threats or to adapt it to changes in other nations' defensive technologies.
While there is admittedly, a large subjective policy component to the question of how much importance to assign nuclear weapons modernization as a means of coping with future security threats, Dr. Bailey overstates the post Cold War risks in this regard. While compelling national security justifications are lacking, existing nuclear explosive packages can, as a technical matter, be integrated into new or modified warhead and bomb systems, and these systems in turn can be mated to new or modified delivery systems, without resort to nuclear explosive tests.
In other words, under a CTBT some of the operational characteristics of nuclear weapon systems can be adapted to changing military missions. Improved casings, radars, altimeters, boost-gas delivery systems, neutron generators, detonators, batteries, integrated circuits, fuzing and arming systems, permissive action links ­ all can be developed, tested, and integrated into nuclear bomb and warhead systems without modifying the primary or secondary components of the nuclear explosive package design. Indeed, Bailey herself cites the case of the conversion of the B61-7 strategic bomb into the B61-Mod 11 earth penetrating weapon for destruction of deeply buried targets, but fails to note that this conversion was carried out and certified for the stockpile by the Stewardship Program without nuclear explosive tests.
If the proliferation of missiles armed with chemical or biological weapons agents becomes a more serious threat to the Untied States and its allies in the future, it may be prudent to include in the U.S. nuclear arsenal some warheads designed specifically for the mission of destroying such agents either in their storage areas or on incoming missiles. (p.5)
It would not be in the US interest to explicitly adopt a posture of using nuclear weapons to deter the use of biological/chemical weapons, since the adoption of this posture would only encourage and legitimize the proliferation of nuclear weapons by currently non-nuclear weapon states facing far more imminent threats of such use than the U.S. Moreover, as a technical matter, it is by no means clear that a new rather than existing nuclear explosive package would be required to execute the Chem/Bio incineration mission, and the feasibility of this mission is questionable in light of the possibilities for delivery via widely dispered submunitions.
Finally, serious threats from the emergence of hostile ballistic missile powers armed with WMD is provided for under the treaty's withdrawal clause, which explicitly allows a right of withdrawal to any party in the event that "extraodinary events have jeopardized its supreme national interests." It hardly seems necessary to jettison the near term benefits of a nuclear test ban merely to massage somewhat tenuous nuclear options for countering future WMD threats, which can be maintained in any case at some reduced level under a CTBT. Indeed, the CTBT's positive contribution to international security might well be such that at least some of Dr. Bailey's future WMD threats fail to mature as anticipated.
Preserving the option of modernizing U.S. nuclear weapons is also important in the context of other nations' emerging defensive technologies. We cannot know what means opponents may develop to render U.S. warheads or delivery vehicles obsolete. Such technological breakthroughs could necessitate a complete overhaul of U.S. delivery systems and nuclear warheads.
Again, as a technical matter, preserving the "option" of modernizing U.S. nuclear weapons to counter "emerging defensive technologies" does not require an ongoing nuclear testing program. Indeed, the most likely initial countermeasures would involve changes to the missile and reentry systems, but not necessarily to the nuclear explosive package. On a political level, Dr. Bailey's concern can only be described as arcane and even bizarre. Didn't the U.S. government just announce its intention to deploy a missile defense system, and wasn't it the U.S. secretary of defense who stated that the U.S. would unilaterally abrogate the ABM Treaty, if necessary, to achieve this objective? If conservative advocates of missile defenses are sincere in their desire to shift defense strategy increasingly toward defenses and away from retaliatory nuclear deterrence of attack, a test ban should be regarded as a welcome adjunct to such a policy. A CTBT would severely limit the ability of future adversaries to build the very kind of sophisticated high yield-to weight MIRVed warheads that could penetrate such a system.
Dr. Bailey is also concerned that as the US changes its delivery systems over time new nuclear explosive packages will be needed for them. After all, in the past new warheads were designed to fit the delivery system, not the other way around. But those days are over. If new missile and reentry systems are required in the future, they can be designed to accommodate the dimensions and performance envelopes of existing nuclear explosive packages. While the resulting combinations might represent less than the optimal yield-to-weight or yield-to-eight ratio achievable with nuclear testing, should anybody really care? In fact, we have already adopted this approach. New Trident II missiles are built to carry older W76 warheads as well as newer W88s, and a modified W87 MX warhead is slated for redeployment under START II on the refurbished single warhead Minuteman III missile.
Will a Test Ban Foreclose Needed Safety Improvements?
"...we can assume that nuclear weapons technology will continue to advance and that new measures to make nuclear weapons safer will be discoveredtesting would be required in most cases before such advances could be integrated into stockpile designs." (p. 6)
Just because a new technology comes along does not mean that it would be cost-effective to rebuild the nuclear arsenal to incorporate it. In theory, with a big enough collector, one could also generate electricity from the sunlight reflected off the moon. Just because a technological possibility exists does not make it indispensable or even sensible. As already noted, the current arsenal is "safe" in that it meets modern "one point" safety standards against accidental nuclear detonation. This characteristic is an inherent function of a boosted primary's nuclear design, and it does not disappear with age. Likewise, the susceptibility of the chemical explosives in nuclear explosive packages to accidental detonation does not increase with age, so as the arsenal ages it is not expected to pose a greater plutonium dispersal risk.
The only question then is do we want to make nuclear warheads "safer" than they are today? Dr. Bailey gives the example of high explosive formulations that are less sensitive to impact. In fact, the Navy was asked in 1992 if it wanted to replace its existing W88 Trident missile warhead with a new version with less sensitive explosives. The Navy decided it could improve the safety of the Trident system more cost-effectively by changing the way it loaded the warhead onto the missile, rather than changing the warhead itself. Moreover, many warhead parts relevant to safety and/or use control - such as detonators, fusing and arming systems, and permissive action links - all can be improved without modifying the nuclear explosive package design. The lesson: accelerate the retirement of any substandard weapons, look for approaches to improved safety that do not involve major changes to the nuclear explosive package design, and minimize the exposure to potential accident environments of those weapons with the greater plutonium dispersal risk.
Are Nuclear Test Explosions Required to Ensure the Reliability of the Enduring Stockpile?
To use another automobile industry analogy..Ensuring reliability means that no "recall" will be warranted.(p.6)
On the contrary, ensuring reliability has always included, and continues to include, having the capability to both detect the need for and execute a "recall" should an "actionable defect" recur in a large sample of warheads. Detecting such defects is a major objective of the Stockpile Surveillance Program.
As noted previously, some less advanced types of nuclear weapons designs do not require testing to ensure reliability. Such designs are relatively simple, and their performance can be calculated and modeled with high confidence. Advanced designs, such as those in the U.S. stockpile, are extremely complicated. They have many variables and several thousand components.With the technology available today, there is no way to simulate nuclear detonation of the high-performance complex designs in the U.S. stockpile. (p.7)
Many times in the past, U.S. nuclear weapons designers were surprised by the results of nuclear tests, which revealed problems the designers had not imagined. The tests showed them that they had not understood conditions and technologies as well as they had thought. Thus while some defects have been discovered through surveillance of the stockpile and non-nuclear testing, other problems with U.S. nuclear weapon designs have been identified solely as a result of a nuclear test. (p. 9-10)
The above statements constitute a compilation of fallacies. First, they fail to distinguish between the complete bomb or warhead system, which may indeed have "thousands of parts," and the nuclear explosive package, which has roughly two orders of magnitude fewer parts.
Second, they fail to distinguish between the tests that have historically been required to certify the nuclear explosive performance of a new nuclear explosive package design, and those intended to confirm, on a random selection basis, satisfactory performance of stockpiled weapons that had been subjected to the stresses of a simulated "stockpile-to-target" sequence and then detonated underground in Nevada. For most of the Cold War, such "stockpile confidence" tests were not conducted, because until the advent of the Reagan Administration the laboratory leaderships considered them a waste of resources. These "reliability" tests merely repeated the "stockpile certification" tests that all new weapon designs underwent prior to quantity production for the stockpile, and of the 13 conducted since 1980, only one revealed a significant deviation from expected performance, which was traced to a tritium maintenance problem and easily corrected without modifying the nuclear explosive package.
Finally, the empirical record of computationally predicted versus measured test yields shows that "with the technology available" the laboratories actually did an excellent job of predicting the performance of the "complex" boosted devices now in the enduring stockpile. The mean deviation of predicted versus radiochemically measured test yields is classified but is reassuringly small, even for first time tests of new boosted primary designs. Nor does the test record support the contention that current complex designs are unpredictably sensitive to small changes in production tolerances and materials, as the shift from laboratory built R&D test devices to fully engineered factory built weapons reveals no significant deviations in nuclear explosive performance.(1)
As discussed in greater detail below, very few problems ­ less than 1% -- were identified "solely as a result of a nuclear test."
In 1997 the [then] director of Los Alamos National Laboratory, Sig Hecker, wrote to Sen. Jon Kyl (R-Ariz.), stating that confidence in the U.S. stockpile had decreased since the last U.S. test in 1992. Hecker also said that several problems, some of them age related, had developed which previously "we would have turned to a nuclear test in the kiloton range to resolve." (p. 7)
This is a rather incomplete synopsis of Hecker's views, which were provided in response to a list of questions sent to him by Senator Kyl, a test ban opponent. It condenses the response to two separate questions. In response to the question, "will confidence in the safety and reliability of U.S. nuclear weapons decline without nuclear testing?" Hecker actually replied as follows:
"The stockpile stewardship and management program, designed jointly by the Department of Energy's Defense Programs and the weapons laboratories, has allowed us to continue to certify the safety and reliability of the stockpile although it has been five years since we last conducted a nuclear test. As anticipated, our confidence in the nuclear stockpile has decreased somewhat during that time frame. This decline in confidence is an inevitable consequence of lack of testing. To date, we have found the decline to be manageable because we have not introduced any new weapons into the stockpile and we still have on hand a cadre of experienced nuclear weapons designers and engineers. Moreover, we have an adequate nuclear test history for the weapons in the stockpile. I have just sent my second annual letter to the Secretaries of Energy and Defense certifying the nuclear weapons we designed to be safe and reliable without nuclear testing. For the longer term, science based stockpile stewardship is designed to develop new tools to better understand the fundamental science and technology of nuclear weapons that will help us shift to basing our confidence in the nuclear stockpile on SBSS, and away from our historic reliance on nuclear testing (emphasis added)."(2)
In the second question, Hecker was asked: "Since the last nuclear test, have there been age-related or other changes in the stockpile that previously would have been addressed by conducting at least one nuclear test? If so how certain are you of the fixes? If your level of confidence in the fixes is not extremely high, how has this affected your view of stockpile reliability?" Hecker replied:
"Yes, there have been several instances since the cessation of nuclear testing in September 1992, where we have found problems, either age related or otherwise, for which in the past we would have turned to a nuclear test in the kiloton range to resolve. In the absence of testing, we have used the methodology of SSMP to evaluate the problem and suggest fixes if required. This has included more extensive calculations, non-nuclear laboratory experiments, comparison to previous nuclear test data, and the extensive experience of our designers and engineers. Moreover, our assessment has been checked against the rigors of peer review by the Lawrence Livermore National Laboratory. We have examined several problems of this nature during this year's certification cycle. At this time, we have sufficient confidence in our solutions to certify the stockpile without a resumption of nuclear testing. If our confidence in the fixes were not sufficiently high, we would not certify the stockpile. Our experience to date in resolving suspected problems has increased our confidence in SSMP and in the process of annual certification (emphasis added)." (3)
Some additional observations by Hecker, not cited in the Cato Policy Analysis, are pertinent to the subject at hand:
"I believe that the SSMP as currently configured and fully funded provides the best approach to keeping the confidence level in our nuclear stockpile as high as possible for the foreseeable future. We recognize that there is no substitute for full-systems testing in any complex technological enterprise. This is certainly true for nuclear weapons. A robust nuclear testing program would undoubtedly increase our confidence. However, our long-term confidence in the stockpile would suffer if we substituted a program consisting of an occasional nuclear test for a robust stewardship program because it would lock us into an empirical approach tied to limited testing data without the benefit of the flexibility and resiliency provided by better scientific understanding (emphasis added."(4)
Hecker certainly realizes, even if Dr. Bailey does not, that in the post-Cold War era "a robust nuclear testing program" cannot be justified by DOD's current or reasonably foreseeable nuclear weapon requirements, and could not be justified politically to the American public and the international community, which overwhelmingly support an end to nuclear explosive testing.
In his responses to Kyl, Director Hecker returns twice more to the theme of the tradeoff between continuation of a modest nuclear test program without the CTBT, and a robust stewardship program with the CTBT, and he repeatedly chooses the latter:
"Again, I would like to add the caution that conducting an occasional nuclear test in lieu of a fully-funded SSMP will jeopardize our long-term confidence in the stockpile. The SSMP is designed to predict and correct problems in the stockpile, whereas an occasional nuclear test would focus primarily on existing problems. It is critical at this time that we focus the attention of our people on being able to do the best possible job without nuclear testing."(5)
"I should also add that in August 1995, when the President made his [zero yield CTBT]decision, we had already not conducted a nuclear test for almost three years. Our budgets had decreased precipitously over the previous six years. Our people were looking to get out of the nuclear weapons program. The production complex appeared hopelessly broken. The prospects of doing an occasional nuclear test was proving to be a barrier to adopt[tion of] a new approach to nuclear stewardship. This situation has turned around dramatically in the past two years with the emphasis on science-based stockpile stewardship. Our people have a renewed commitment to stockpile stewardship and an enthusiasm for the development of a new methodology, based on rigorous science and engineering, to ensure the safety and reliability of the stockpile." (6)
"The 1958-61 test moratorium provides a relevant comparison. At that time, some stockpile problems were fixed, and there was confidence that the solutions worked. When the moratorium ended and testing resumed, the "fixes" were found to be inadequate." (p. 7)
WRONG. The 1958-61 moratorium does NOT provide a relevant comparison. Immediately preceding or during the 1958-61 moratorium, nine warheads were developed and deployed in "crash" programs, when the United States imprudently rushed some 6500 inadequately tested warheads per year into the stockpile. Seven of these new warhead types were never tested before deployment with aged end-of-life components, and developed problems related to a common cause ­ aging of their tritium reservoirs. This failure was particularly acute given the lack of experience at the time with the behavior of boosted warhead designs.
Today we have an additional 30 years of test experience with such boosted weapons. Defects in the other two warheads were also directly traceable to the crash nature of the program in the moratorium era. One underwent a change in high explosive during the moratorium and was stockpiled without a nuclear proof test. The other was designed with a known inattention to the problem of neutron radiation external to the warhead, and then deployed without a neutron vulnerability test. The resumption of testing uncovered a severe vulnerability problem. Finally, all nine of these problem warheads have long since been retired from the stockpile.
The experience and understanding of the experts who designed the current U.S. nuclear weapons have not been well documented because the entire U.S. nuclear weapons program was predicated on the absolute need for an ability to conduct testing throughout the life of the design. (p. 8)
This is an excessively dire and therefore misleading view of the state of U.S. nuclear weapons knowledge. While the specific technical rationales for certain design decisions lack extensive contemporaneous documentation, DOE is seeking to fill in these gaps through improved archiving and interviews. Much of the accumulated U.S. nuclear weapons knowledge is embodied in the nuclear test calibrated nuclear design codes, which in the hands of skillful users yielded remarkably accurate performance predictions when new designs represented iterations or modest extrapolations from previous test experience.
Moreover, it is emphatically NOT TRUE that "the entire U.S. nuclear weapons program was predicated on the absolute need for an ability to conduct testing throughout the life of the design. For example, from 1965 to 1980, no underground tests were conducted for the primary purpose of identifying or developing corrections to stockpile problems. According to Sandia National Laboratory Director Paul Robinson:
"Historically, only a small fraction of our nuclear tests were for the purpose of evaluating the stockpile's health, because we could depend on a variety of other evaluation techniques. The introduction of new and improved non-destructive surveillance techniques should provide us the ability to detect problems in the stockpile and to maintain or even improve the safety of our systems.
"A principal concern for the future is that, without carrying out nuclear testing, nuclear design engineers (at Los Alamos and Lawrence Livermore labs) may not be able to confirm that a fix proposed to solve a stockpile problem does, in fact, work without introducing some other unintended and unforeseen problems. This concern has more to do with whether we will end up unable to correct problems, once they are detected, than with a general loss of confidence that might result from the elimination of nuclear testing (emphasis added)." (7)
In fact, the extent of U.S. dependence on nuclear explosive tests to maintain stockpile weapon "reliability" is known rather precisely known. A 1996 tri-lab study of the Stockpile Surveillance Program reveals that, of some 830 specific recording "findings" of defects in stockpile weapons from 1958 to 1993, less than 1% were "discovered" in nuclear tests, and all but one of these tests involved weapons that entered the stockpile before 1970 and are no longer in the U.S. nuclear stockpile today.
After 1970, one warhead maintenance problem, related to the effect of tritium decay on the design yield, was discovered in a Stockpile Confidence Test (SCT) of the W84 warhead (now in the "reserve" stockpile) for the GLCM missile eliminated under the INF Treaty, but the problem was easily rectified without modification of the nuclear assembly system. Another three underground tests confirmed the existence of problems in the high explosive of the W68 SLBM warhead (fully retired) and in the cold temperature performance of the (then new) Insensitive High Explosive (IHE) used in the W80 ALCM, and the "Mod 4" version of the B61 bomb. But only four out of 141 (i.e. about 3%) of "Product Change Proposals" to war reserve weapons specifically required underground nuclear explosive tests to develop or confirm the corrective actions. In addition, three routine SCT's reportedly served the dual function of confirming fixes to already identified problems. Hence a total of 11 tests, or less than 3% the 387 tests conducted after 1970, were directly related to maintaining the reliability of the existing stockpile.(8)
When asked to quantify the reduction in stockpile confidence resulting from the tran-sition from underground testing to the stockpile stewardship and management program (SSMP), Sandia Director Robinson noted:
"Because we cannot guarantee how successful SSMP will be, it follows that I cannot quantify any reduction in stockpile confidence that might eventually result. What I can say, however, is that the kinds of stockpile problems that would lead to such an erosion in confidence seem unlikely during the next 5 or 10 years. Beyond that time frame, however, as the base of experienced individuals disappears, it becomes much more difficult to make any predictions." (9)
In the light of such testimony by highly qualified individuals with detailed nuclear weapons knowledge, one wonders why Dr. Bailey does not feel similarly constrained from making dire predictions that the SSMP will inevitably prove unable to maintain a safe and reliable stockpile.
Can't Remanufacture of Warhead Components Maintain Reliability?
Why can't measures other than nuclear testing ­ surveillance of the stockpiled weapons, non-nuclear testing of materials and components, and rebuilding of aging weapons --­reveal problems and provide high confidence solutions. To some extent, they can and already have. However, we have learned from experience that weapons in the U.S. stockpile can have design flaws or problems that are introduced as a result of field handling. A particularly difficult problem to address is what nuclear testing experts call the "unknown unknown" ­ the unanticipated problem that is exposed only by the extreme stresses encountered in the environment of a full-scale nuclear test. (p.9)
It would seem that rebuilding warheads regularly to replace their parts and materials would correct age-related problems that develop in nuclear warheads. Indeed, Russia's approach to ensuring reliability depends on rebuilding; it produces thousands of weapons per year to replace aging warheads in its inventory." (p. 10)
Dr. Bailey seems to take the odd (and indefensible) position that warhead surveillance and component remanufacture will work in a technologically lagging and nearly bankrupt Russia, but cannot be made to work in the U.S., the richest and most technologically advanced nation in the world. Moreover, Russia is no longer producing "thousands" of warheads per year to replace aging warheads in its inventory. The actual number is closer to a few hundred, and this number will further diminish with time as Russia's budget crisis continues.
In the case of the U.S. arsenal, rebuilding warheads to ensure reliability is not currently an option. Some components and materials are no longer available, and there is no way to duplicate them. It may not be possible to determine, in the absence of nuclear testing, what the functional equivalent of a particular component or material is. And there is a Catch-22: Even when new U.S. production capabilities are built, it will be impossible, absent nuclear testing, to validate the new plants, processes, and people. Nuclear tests are the only known means of demonstrating that new production lines produce functionally identical products. (p.10)
The above statements fail to distinguish between non-nuclear component production capabilities, which are currently functioning and producing replacement and new components for the stockpile, and nuclear component fabrication capabilities, which have not been fully reestablished. This is hardly cause for alarm, however. While limited life components, such as neutron generators, tritium reservoirs, and batteries, must be replaced periodically, the plutonium pits and uranium-lithium secondary components have as yet indeterminate life spans, conservatively estimated to be on the order of 50 years or more.
There is ample time, therefore, to reestablish plutonium pit recycling and fabrication capabilities, and in light of ongoing arms reductions and the likelihood of further reductions, there is an advantage to proceeding, to avoid hasty, very expensive, but potentially redundant investments in plutonium fabrication capabilities. A limited capability for pit fabrication has been reestablished at Los Alamos, and current efforts concentrate on precisely the issue of concern to Dr, Bailey ­ "certification" of a new process for casting plutonium pits through carefully diagnosed hydrodynamic experiments at Los Alamos and NTS. Likewise, facilities for modification of secondary components are now operating again at Oak Ridge.
As for the role of nuclear tests, while undoubtedly adding to confidence in the remanufactured product, even if successful a nuclear test does not in itself guarantee that subsequently manufactured devices will perform as intended. They are in fact one of the least viable means for "demonstrating that new production lines produce functionally identical products." Statistically valid sampling, detailed inspection, and non-nuclear testing of warhead components, including full scale and intensively diagnosed integrated testing of the nuclear assembly system, are the best way of verifying the "functional identity" of the reestablished product lines. Underground nuclear explosions are too expensive, and often provide too highly integrated a result, to be of much use in identifying the root cause of any system malfunction.
Is the CTBT verifiable?
...any adversary that covertly tests ­ while the United States forgoes testing ­ can gain significant military advantage.
...two key questions must therefore be addressed: what is the minimum yield of a nuclear test that can provide militarily significant information, and can the CTBT verification system detect tests at that level.
...Testing at any yield, regardless of how low it is, may provide militarily significant information to a proliferator and, perhaps, to and advanced nuclear weapons state. (p.11)
Clearly, this must be regarded as an extreme position. Bailey glides easily between "significant military advantage" and "militarily significant information," but they are not the same concept. Given the advanced state of U.S. nuclear weapon capabilities, it would take much more than a few covert tests for any state to gain "significant military advantage" over the United States. Did India or Pakistan gain significant military advantage over the U.S. or any other nuclear weapon state as a result of their recent tests? Can anyone honestly say that a covert nuclear test by Russia today would confer upon it a significant military advantage over the United States? It is one thing to acquire nuclear weapons information through one or a few covert low yield tests. It is another matter entirely to exploit that information in a manner that preempts timely detection of production and deployment and a deterrent response, and therefore confers a meaningful military advantage.
The International Monitoring System (IMS) will not be able to detect, with any significant degree of confidence, nuclear testing below one kiloton. If the test is evasively conducted, the system will not detect a test of several kilotons.
These misleading assertions deserve a closer look. First, there is recent demonstration that the IMS will be able to detect and identify non-evasive explosions of less than 1 kiloton in some strategically important areas. In August 1997, a small seismic event was detected in the area of Novaya Zemlya, Russia's primary nuclear test site. At first, ambiguous preliminary U.S. seismic intelligence data, along with simultaneous preparations for underground "subcritical" experiments at the Russian site, suggested that this event was a secret nuclear test. Additional data from stations in the still incomplete IMS quickly served to more precisely locate the event well off-shore in the Kara Sea, and revealed seismic signatures characteristic of an earthquake, not an explosion. Had this been an underground nuclear test, its magnitude (3.3) would have corresponded to a yield of less than 100 tons (0.1 kilotons) in the absence of evasive measures. A nearby event identified as an earthquake in January 1996 was a factor of ten smaller (2.4), corresponding to a yield of about 10 tons. This is much better than the minimum expected global seismic event detection and identification capability that Bailey and others have often mistakenly characterized as the best that can be achieved (i.e.1 kiloton non-evasively tested, magnitude 4). It is simply not cost effective or sensible to attempt to achieve a uniformly low seismic threshold for all areas of the globe and against all "possible" evasion scenarios, no matter how implausible these may turn out to be in practice. Such a capability would result in a huge increase in the number of seismic events detected in low threat regions, covering most of the globe, that would require further processing and identification.
Moreover, the seismic capabilities to monitor the CTBT go beyond the IMS. In addition to the IMS's 170 seismic stations, for example, there are more than 10,000 other seismic stations providing dense regional coverage -- in many cases providing a better detection capability than the IMS. Also, the United States is deploying enhanced capabilities as part of its own national intelligence means that will exceed those of the IMS in important areas.
Finally, the capabilities of the verification regime go beyond seismic monitoring to include hydrophone, infrasound, and radioactive debris detection capabilities, voluntary confidence building measures (such as voluntary site visits and cooperative transparency measures) on-site inspections at the request of 3/5 of the treaty's Executive Council, and the ever present possibility of human intelligence and leaks regarding clandestine testing activities.
The most likely cheating scenario may be an underground nuclear explosion in a cavity. That would muffle the energy, reducing the blast signal by as much as a factor of 70. Thus, a 1 kiloton explosion could be made to look seismically like a 14 ton explosion; a 5 kiloton explosion could look like a 70 ton explosion. (p. 12)
The effects of "decoupling" are well documented. For example, the United States conducted two nuclear tests in the Tatum salt dome located at Chilton, Mississippi. Sterling, the test conducted on December 3, 1966, had a yield of 380 tons. The apparent seismic yield was only 5.3 tons, a reduction by a factor of 71.7. (Footnote 12)
How Probable Is Successful CTBT Evasion via Cavity "Decoupling" ?
This synopsis is seriously misleading. Much more can be said about the prospects for successful evasion via "decoupling." In reality, the prospective evader would be very far from certain that cavity-decoupled explosions as large as several kilotons would escape detection and subsequent identification as nuclear tests. This is particularly true for states with little or no nuclear test experience. Cavity decoupling is a major technical undertaking, requiring specialized knowledge and equipment and hundreds of skilled personnel. Decoupling even low-yield explosions would a difficult and uncertain task.
To begin with, even so called "full decoupling" means not the absence of a seismic signature, but a difficult-to-predict reduction in the seismic signature, ranging from the experimentally observed maximum of a 70 -fold reduction at the low frequencies (< 6 hz) that propagate long distances, down to only a factor of seven reduction (at 20 hz) for higher frequency waves propagating over regional distances (this significant detail is omitted from Bailey's analysis).
Far from being "well documented," as Bailey asserts, these "full decoupling" factors are based on analysis of the 380 ton Sterling event and the even smaller Diamond Beech/Mill Yard tests in volcanic tuff at the Nevada Test Site. Whether these results hold for larger decoupled explosions on the scale of kilotons in correspondingly larger cavities and different geologic media is simply not known, and will be obviously very difficult to establish once the test ban goes into effect. Data from a 10 kiloton partially decoupled explosion carried out by the former Soviet Union in a salt dome, now located in Western Kazahkstan, indicate that teleseismic signal amplitudes were reduced only by a factor of ten relative to a tamped (i.e. well coupled) explosion of similar yield, suggesting that the decoupling factor drops off rapidly if the explosion is too large for full decoupling within the cavity.
Hence, the postulated "full decoupling" factors of 7-70 (depending on the frequency) are obtainable only if the yield of the device and the size and shape of the cavity are appropriately matched. In the proliferation evasion scenario, the yield of the explosive device will not be known in advance with any degree of precision, and thus the appropriate match with cavity size cannot be assured, making it likely that only partial or possibly no decoupling will be achieved.
Indeed, based on Russian and U.S. test experience, such a scenario involves a substantial risk of containment failure, leading to discovery of the test through large-scale venting of radioactive gases into the atmosphere. The United States and Russia developed their containment technology largely through trial and error based on repeated experiences at well-studied test sites. A prospective evader without extensive nuclear test experience would have to consider that the probability of getting it right the first time, at an untried location, is at least highly uncertain and probably quite low. This risk was demonstrated recently when one the recent low yield Pakistani tests vented radioactive debris into the atmosphere which was subsequently collected by U.S. monitoring aircraft. Indeed, the use of a new site raises the risk of containment failure even when the decoupling is attempted by an experienced nuclear weapon state.
In the event the seismic signal from a cavity explosion of a few kilotons is only partially decoupled, it would readily be detected and discriminated from earthquakes of comparable magnitude, so the penalty for not doing the job exactly right is severe. Human intelligence, data from national technical means, and on-site inspections, would pose a substantial risk of further identifying this "point-source" explosion as being nuclear rather than chemical in origin.
Even if containment failure can be avoided, there is still the problem of preventing the delayed leakage or "seep" of radio-isotopes from the cavity due to barometric pressure. Radioactive contamination from the cavity may also finds its way into the water table, where it can be detected through drilling conducted during an on-site inspection, and the cavity must also be protected against subsequent collapse to avoid creating a telltale subsidence crater at the surface.
Due in part to its lack of joints and fractures which might allow seepage of radioactivity from the secret blast to the surface, domed or thickly bedded salt is the preferred medium for decoupling. However, the locations of major salt deposits capable of sustaining a cavity explosion on the order of one kiloton or more are known.
Creating a decoupling cavity is a delicate balance between the minimum depth required to fully contain the cavity-generating explosion, and the maximum depth at which a stable cavity of the desired size can be sustained without being crushed by the pressure of the overburden. If solution mining techniques rather than an explosion were employed to create the cavity, tens or hundreds of millions of gallons of brine would have to be disposed of without drawing attention to the project. And given that the hydrostatic pressure of the brine in the cavity helps to support the weight of the overlying rock, evacuation of the brine from the cavity in preparation for the test would make the stability of the cavity highly uncertain. Existing solution mined cavities are elongated and irregular in shape, creating the likelihood of an unpredictable and possibly sharp reduction from the nominal "full decoupling" values assumed in Bailey's paper.
As a consequence of these and other difficulties, such as concealing or masking such preparations from the prying eyes of U.S. intelligence, the CTB inspection system, and one's own citizens, most experts agree that attempts at full decoupling are completely impractical for yields above a few kilotons and highly uncertain at any yield for nations with no experience with conducting underground nuclear detonations. For example, the full decoupling of a 5 kt explosion in a salt dome would require a deeply buried cavity with a minimum diameter of 86 meters (282 ft), big enough to contain the Statue of Liberty on its pedestal with room to spare. And yet Bailey tosses off the possibility of decoupling a 5 kiloton explosion as though it were just another walk in the park.
Bailey raises the possibility that a nation might conduct a test in the open ocean, where it would be relatively easy to detect but difficult to determine who did it. She is right about that; it is quite possible that the international community would be unable at first to attribute an open ocean explosion.
But this does not mean that there would be no risk to the violator. Once detected, the US and other nations would go to great lengths to figure out who did it. Secret operations are always vulnerable to leaks, both before and after the fact. The movements of naval vessels and even commercial shipping around the world are extensively monitored by the U.S. and other Naval intelligence services, and by ocean reconnaissance satellites, and all their communications are likewise subject to monitoring. Hence the support vessels involved in such an operation are potentially subject to detection and surveillance. Any debris from the bomb's platform (boat, submarine, etc) not vaporized in the blast might be traceable back to the point of origin. There is also some possibility that the characteristics of the radioactive debris from the nuclear explosive could be traced back to the maker.
There is only one reported case of a publicly unattributed open ocean explosion, the still-unresolved 1979 event in the Indian Ocean. If this method of evasion is so easy, why haven't we seen more of it? And if nations have not had reason to use this method in the past, why would we start to see more of it under the CTBT? We will not. And even if we did, the US could reconsider its adherence to the Treaty, as could other nations that have greater reason to feel threatened by such developments than the United States.
This paper largely misses the point on verification. One hundred percent certainty is not the goal. The goal of any verification system is to deter all violations of the treaty, while assuring detection of violations that would deprive a party of the security benefits it derives from the compliance of the other parties. Thus the probability of detecting violations must be high enough so that potential violators will believe that the risks of being found in violation outweigh the expected benefits of the illegal act. Conversely, the law-abiding nations must be convinced that the security risks posed any by undetected violations are substantially less than the security benefits of the treaty.
The CTBT verification system meets these conditions. In general, the higher the yield of a nuclear test, the greater the chances that it will be detected and identified as a nuclear explosion. Above a few kilotons, these probabilities are high irrespective of location and the mode of emplacement. It is true the treaty's verification system will not have a uniformly high-confidence capability worldwide to detect and identify very low-yield nuclear tests (i.e. those ranging from a few pounds to a few hundred tons). However, at the higher end of this spectrum, events with seismic yields of tens to hundreds of tons can be readily detected in many areas of the globe, but discrimination of potential nuclear events from large point-source chemical explosions remains a problem. The treaty addresses this issue by providing for voluntary notifications and exchanges of data regarding the conduct of large chemical explosions, and by mandating procedures for the conduct of on-site inspections of the vicinities of suspect events. Tests below a few hundred tons do not permit an adequate assessment of deuterium/tritium boosting, a major performance indicator in advanced nuclear weapons. A full yield proof test of a boosted primary for a two-stage thermonuclear device requires a test in the range of several kilotons or higher.
And for an aspiring nuclear weapon state lacking sophisticated computational design code capabilities, testing kiloton range fission weapon designs at greatly reduced yields can be a dicey proposition, creating the possibility of an overshoot that ruptures the containment planned for the reduced yield, thereby risking disclosure of the test and harm to valuable scientific personnel. Data from such a modified device, while possibly leading to the discovery of errors in computer design codes, or improving confidence in such codes, does not allow confident certification of the desired nominal yield.
Finally, there is the problem of inadvertant disclosure of the secret activity - for example through discussions at scientific conferences - and the ever present likelihood that among the project personnel there will be at least one "whistleblower" - a Mordechai Vanunu -who will expose the illegal test to the world. Under such circumstances, a proliferant nation would have ample reason to conclude that the risks of detection, including the diplomatic and economic consequences likely to flow from being found in violation, are greater than the benefits from conducting such tests.
The technical problems with CTBT verification are complicated by another difficulty the problem of gaining political consensus for a response when noncompliance with the treaty is suspected. In the case of the current nuclear testing moratorium, there have been indications that Russia may have conducted low-yield tests. Yet there have been no U.S. protests or inquiriesRegardless of the reason, it is clear that challenging nations suspected of illegal behavior can be politically very difficult.
It is difficult to take seriously such concerns regarding CTBT compliance in a paper that otherwise opposes entry-into-force of the very mechanisms that would make it easier to "challenge nations" regarding their nuclear testing activities. On the question of recent Russian test activities at Novaya Zemlya, Bailey is flat wrong. The U.S. government has made repeated inquiries about these activities, and the consistent Russian response is that they are performing subcritical experiments, in a manner similar to our own underground experiments at the Nevada Test Site. The current ambiguity surrounding these activities was predicted by independent verification analysts, and is the inevitable outcome of allowing continuing underground explosive experiments at existing nuclear test sites. (10)
Can other nations "legally cheat"?
If other nations chose to apply a less restrictive definition than does the United States, they could conduct very low-yield tests in which the nuclear energy released was less than, for example, a four-pound equivalent of high explosives ­ what the United States refers to as hydronuclear testing."
It was principally at United States behest, and that of other nuclear weapons states, that a more detailed and restrictive definition of prohibited activity was not included in the treaty. But the difficulty of reaching agreement on a more precise definition might well have consumed months of negotiating time without any guarantee of a successful result. So the Parties opted for another approach, a broad definition banning all nuclear weapon test explosions, and any other nuclear explosion, and in August 1995 both the United States and France formally announced their view that the treaty prohibited all weapon tests that resulted in a prompt critical assembly of fissile material. None of the negotiating parties to the treaty dissented from this view of the treaty's scope, although some states regretted that the treaty did not go farther to ban other kinds of nuclear weapons-related experiments. I believe that the negotiating record will show that in discussions among the five nuclear weapon states, it was made abundantly clear to the Russians, who did not object, that a four pound nuclear test is a prohibited test under the CTBT.
However, whether Russia is or is not testing at the four pound level is almost a moot point. In deciding in favor of a so-called "zero yield" threshold, the United States made the unilateral determination that such testing was not required for its own security, and that well diagnosed hydrodynamic experiments coupled with computations provided an experimental result that was superior to hydronuclear experiments, which require significant modification of the weapon assembly system and extensive computations to yield a more uncertain result. But such experiments could be of some limited use to proliferant states, and thus, on balance it was better to ban them.
Will Stockpile Stewardship Succeed?
Since Dr. Bailey tends to overstate the role of nuclear tests in maintaining the safety and reliability of an already test proven, enduring stockpile, she likewise overstates the challenges faced by the program designed to replace nuclear testing with data from computations and experiments. While I tend to sympathize with some of her criticisms of the SSMP, most of her assertions are undocumented and rather open-ended, and some are clearly exaggerated.
The SSP facilities will not be completed for a decade, perhaps longer. In the interim, the stockpile could erode seriously because the United States would have inadequate capabilities to detect and fix the problems that arise. (p.16)
All of the major approved stockpile stewardship facilities, such as NIF, DARHT, Contained Firing Facility, and Atlas, are scheduled to be operational by 2005 at the latest. Moreover, with the possible exception of the improved dynamic radiography capability represented by the two-axis DARHT facility, none of the other new facilities are critical to the capability to maintain the stockpile in the next five to ten years.. They are being constructed to retain, attract and train the next generation of stockpile stewards.
The SSP is designed to address research and development needs; it does not include a program for rebuilding U.S. nuclear weapons. (p.17)
While the SSP certainly emphasizes the retention and replication of research and development capabilities, it is inaccurate to state that it does not include a program for rebuilding U.S. nuclear weapons. Billions of dollars are being expended on consolidating, modernizing and reconstituting production capabilities for both nuclear and nonnuclear components. If the paper means to imply that more attention should be paid to the problem of remanufacturing existing weapons, and rather less attention paid to ensuring future capabilities to design new ones, I agree. But it is apparent in very the next quotation that Dr. Bailey does not mean this.
SSP managers are likely to limit the types of experiments they are willing to undertake because of adverse reaction from anti-nuclear activists. This could make the SSP less relevant to nuclear weapons design. (p.17)
Dr. Bailey is difficult to please. First she accuses the SSP for paying too much attention to R&D at the expense of weapon remanufacture, and then she turns right around and suggests that SSP managers are poised to blunt U.S. nuclear weapon design capabilities in order to placate "anti-nuclear activists." As one of those frequently identified as such, I detect no such tendencies on the part of DOE, unless one regards the various authors of the zero yield policy, such as President Clinton, Secretary Perry, and Vic Reis, as "anti-nuclear activists."
The credibility of the U.S. nuclear deterrent may erode regardless of the SSP's success because the reliability and viability of the U.S. arsenal will not be demonstrated regularly. (p.17)
This statement belongs to the realm of theological conviction, and I can offer no comment, other than to pose the question, where on the globe, now or in the future, would U.S. security interests be advanced by a resumption of nuclear testing for the psychological purpose of reinforcing the "credibility" of U.S. deterrent threats to use nuclear force?
Maintaining Testing Capabilities
In the absence of testing, however, the capabilities to test cannot be maintained. (p.17)
...keeping highly skilled, knowledgeable people at hand will be virtually impossible absent testing. (p. 18)
This assessment is contradicted by LANL Director Hecker:
"Right now, we find that most of the key skills are being exercised with the subcritical tests at NTS. We are also working diligently to keep some skills alive by utilizing some of the techniques and people, previously at the test site, here at our laboratory."(11)
Does the CTBT Contribute to Nonproliferation?
A proliferator may want to test its nuclear weapons for political reasons, as India and, particularly, Pakistan did in 1998. However, nuclear testing is not a prerequisite to acquiring a workable, reliable arsenal. (p.20)
Today, without testing, relatively sophisticated weapons (nonboosted, implosion-type devices) may also be designed with high confidence. (p.20)
In summary, the CTBT will not create a significant or meaningful obstacle to nuclear proliferation. A nation may quite feasibly design, build, and stockpile effective nuclear weapons without testing. (p. 21)
Bailey raises the political motivations and consequences involved in nuclear tests, but then utterly fails to account for their effects in her far too swift dismissal of the impact of a CTBT on proliferation. She focuses solely and inaccurately on what might be accomplished by proliferant states under a CTBT, and neglects entirely to analyze the types of weapon developments that would be prevented or severely constrained by the treaty.
A global ban on nuclear explosions will obviously affect particular nations differently, depending on their technological level and the resources plausibly available for the proliferation effort. Bailey likewise neglects the other numerous technical requirements for achieving a nuclear weapons capability, not the least of which is obtaining the requisite types and amounts of fissile and other relevant weapon materials and components, many of which are tightly controlled. Here too the picture is complex, with very few states enjoying unrestricted access to both highly enriched uranium or separated weapon-usable plutonium, and the industrial and technical infrastructure needed to produce fully-engineered nuclear explosives.
South Africa has demonstrated that "gun-type" bombs using highly enriched uranium can be built without nuclear explosive tests, although even in this case, explosive tests would be very useful in reducing uncertainty in the expected yield. Bailey considers the case of non-boosted implosion-type weapons, which she asserts generally "can be designed with high confidence without testing." Not only does she fail to distinguish between the impact of a test ban on the development of different types of unboosted implosion weapons, but the issue is not merely whether such weapons can be merely "designed" without testing, but whether they can be stockpiled with "high confidence" without testing.
Particularly in the case of first-time proliferators, nuclear explosive tests would confirm not only the physics design, but also the quality and accuracy of the materials science, weapons engineering, and manufacturing processes employed in actually producing the nuclear explosive package, and its ability to function after withstanding the simulated rigors of its "stockpile-to-target" delivery sequence.
Implosion weapons are presumably of considerable interest to prospective proliferators because much less fissile material is needed for an implosion weapon than for a gun-assembly device for a given yield. Further, implosion designs can use plutonium as well as HEU. In the most straightforward design, a solid core or cylinder of plutonium is surrounded by a neutron reflector tamper, which in turn is surrounded by high explosive. While the yield of such a design can be predicted using modifications of commercially available nuclear hydrodynamic computer codes, accurately predicting the yield is more difficult than predicting the yield of a gun-type device. The geometry and density of the final supercritical assembly, and hence the number of critical masses represented by the fully imploded pit, is harder to predict, and this may translate into larger uncertainties about the resulting yield, again depending on the technical abilities available to extract the necessary time, velocity, and density measurements from carefully diagnosed experiments.
However, such "solid pack" implosion designs require relatively larger amounts of both high explosive and fissile material to achieve the number of assembled critical masses needed for a sizable nuclear explosion. When assembled, this configuration is not inherently safe against the possibility of achieving nuclear yield in an accidental detonation of the high explosive, and the yield-to-weight ratio of such a fully weaponized device is likely to be insufficient for long-range delivery by ballistic or cruise missiles.
To pose a more credible long-range missile threat, a proliferator might well seek to develop so-called "levitated pit" or "hollow core" weapons that employ the principle of the "flyer plate": driven by the chemical explosive, concentric shells of reflector/tamper and fissile material gain momentum as they accelerate inward through free space before converging and rebounding at the center. This produces higher compression of the fissile material, allowing hollow core designs to be lighter and use less fissile material to achieve the same yield. Relative to solid pack nuclear warhead designs, the physics and nonnuclear experiments required to verify the performance of these designs are more complicated, and the possibility for error is greater.
Without nuclear explosive testing, a technically sophisticated proliferator could have confidence that a conservatively designed weapon would work, but considerable uncertainty would persist about its yield, and the design would not approach the optimum in terms of its yield-to-weight or yield-to-volume ratios, reducing its effectiveness for missile delivery. Moreover, the yield of such relatively lightweight, untested pure fission weapons intended for longer range missile delivery is probably limited to a few tens of kilotons.
Thermonuclear Weapons
Bailey's insertion of the qualifier "nonboosted" before "implosion weapon" merely begs the question of the impact of the CTB on single-stage boosted fission weapons and two-stage high-yield thermonuclear (TN) weapons. Her remarks do not address this issue, which happens to be the very area where virtually all informed observers -- both pro and con -- agree the CTBT has its greatest strategic impact.
In a typical modern boosted fission weapon -- typically the first stage or "primary" of a two-stage high yield thermonuclear weapon -- the rate at which the compressed plutonium or highly-enriched uranium undergoes fission is "boosted" during the explosion phase by a burst of additional energetic neutrons from fusion reactions in deuterium-tritium gas injected into the center of the core immediately prior to detonation. The quantity of high explosive and fissile material in a boosted device having a yield of a few kilotons can be made sufficiently small to be made very safe from the standpoint of accidental detonations; that is, the chance of a nuclear yield resulting from accidental detonation of the high explosive at a single point can be made extremely small (less than a one-in-a million chance of exceeding four pounds is the U.S. safety standard). Since DT burning does not begin until the fission energy release has reached at least 100 tons of TNT equivalent, and since in an actual weapon, mechanical rebound and thermal expansion of the fissile material both occur prior to boosting, non-nuclear testing with surrogate materials cannot provide high confidence that the boost phase of a nuclear device will operate as designed.
In a staged thermonuclear device, the radiation from a fission or boosted fission primary is partly trapped and re-irradiated within a heavy metal case to heat and compress a "secondary" component comprised of fission and fusion materials. Early conservative thermonuclear designs used heavy unboosted primaries with primary yields on the order of a hundred kilotons or more. Modern staged thermonuclear warheads use lightweight boosted fission primaries with primary yields on the order of a few to about 15 kilotons and total weapon yields ranging from tens of kilotons to a few megatons, with typical missile warhead yields in the range of a few hundred kilotons.
Perhaps a very few technologically advanced nations might have -- or be able to acquire -- the technical potential to design, engineer, and produce thermonuclear weapons without nuclear explosive tests or test data, but these weapons are likely to be heavy single-stage devices, or possibly heavy two-stage devices with heavy high-yield primaries. Perfecting the design of an optimal yield-to-weight, two-stage thermonuclear design for long range missile delivery, with a yield of several hundred kilotons, has in the past required - and some would argue can only be achieved with - at least partial yield testing of the secondary component.
Radiation implosion of the secondary and ignition of the fusion fuel of a modern staged high yield thermonuclear weapon can be verified experimentally only with nuclear explosive testing beginning at around 10-20 kilotons. This is the primary technical reason why the CTBT remains both an important arms control and nonproliferation measure.
In sum, from the technical perspective, a CTBT is important because the nuclear weapon establishment of a prospective proliferant cannot verify that its weapon codes accurately predict nuclear yield without verifying the accuracy of the computational modeling for the explosive disassembly phase of the weapon. For this, it needs nuclear test data in the kiloton range or higher, or access to historical nuclear test data or nuclear test-calibrated codes. Therefore, full-scale nuclear explosive tests are highly desirable for all but the lowest technology designs, not only to certify the yield of fully-engineered devices, but also to improve the predictive power of nuclear weapons design codes and to optimize designs with respect to the yield-to-weight and yield-to-volume constraints of delivery vehicles.
From the political perspective, which is after all the context in which real world decisions about weapons and national security are actually made, the CTBT likewise remains an undeniably important instrument of political and geostrategic restraint. Bailey's remarks miss the essence of the political as well as technical importance of the CTBT to nonproliferation. Governments do not make important national security decisions based solely, or even primarily, on what their defense scientists say they can do, but on what the majority of the body politic -- or at least its most highly organized and influential elements -- are demanding at any given time in the never ending quest for political power. In this context, the conduct of underground nuclear test explosions can influence the future course of nuclear weapons proliferation, both "vertical" and "horizontal." One can imagine, for example, the pressures that mounted on the political leadership in Pakistan in the wake of the Indian nuclear tests in May.
Is the Future of the NPT at Risk Regardless of the CTBT?
Dr. Bailey's arguments in this section (p.21-22) are puzzling and, to the extent that I understand them, they tend toward self-contradiction. The burden of much of her paper is that the CTBT will undermine the safety, reliability, and deterrent credibility of the U.S. nuclear arsenal. In this section, however, she attributes these views to the non-nuclear weapon state parties to the NPT, and then says the CTBT won't satisfy their desire for "nuclear erosion" because the U.S. and other nuclear weapon states "are establishing programs designed to ensure that their stockpiles will remain safe and reliable--despite the testing ban." Hence many states "are likely to perceive that the CTBT is not the disarmament measure they anticipated."
Here Dr. Bailey has suddenly reversed field and headed in the opposite direction, arguing that the desired nuclear erosion will be "effectively undermined by a successful SSP," the very program she has just condemned as an ineffective substitute for nuclear testing. She then leaps to the daring if not bizarre conclusion that embittered non-nuclear weapon states will then "probably try to use the threat of unraveling the NPT as leverage to terminate the SSP and equivalent programs in Russia, China, France, and the United Kingdom." I think it best not to try further to sort this one out, so I will move on.
Is the International Norm Argument Meaningless?
...the international norm the CTBT would create is as meaningless as similar norms created by some other arms control treaties.
Dr. Bailey would appear to have little use for international norms. History is replete, she says, with examples of how "some nations readily dismiss treaty norms." In support of this contention, she cites Iraqi and Russian violations of the Biological and Toxin WeaponsConvention and numerous alleged violations of the norm allegedly established by the NPT "when the treaty went into effect in 1970." Bailey apparently believes that instances in which historical norms have been violated altogether vitiates their value.
Norms are codes of behavior, usually but not always embodied in laws, conventions, charters, treaties, and the like, that enjoy near universal adherence even though the police and judicial power needed to enforce them is not always available. The NPT in 1970 did not fit this description. The lack of readily available enforcement power is obviously especially acute in the international sphere. But that by no means vitiates the value of efforts to establish norms of conduct within and between nations. Would Bailey likewise reject efforts to establish universal observance of basic human rights? Would she have rejected as useless British efforts in the first half of the 19th century to abolish the slave trade, even though slavery still persists even today in certain remote areas of the globe?
More to the point, perhaps, China and France came to observe the global norm of non-testing in the atmosphere long before they officially adhered to the Limited Test Ban Treaty. Likewise, the NPT has taken 30 years to reach near universal adherence. Should we cease to cultivate this norm just because a few states, such as India, Pakistan, and Israel remain outside this treaty -- states whose conduct has already been at least partially constrained by the global norm of nonproliferation?
The human ascent from club-wielding cave dweller to, hopefully, something more is all about the ever broadening observance of norms, whether it be the integrity of data in scientific inquiry, the obligation to come to the aid of seafarers in distress, the treatment of prisoners of war, or the banning of chemical and biological weapons. Bailey only has eyes for the club, and its continuing evolution into ever more lethal instruments for mass annihilation.
Does the "Clinton CTBT" Give Extraordinary Powers to the International CTBT Organization?
"The treaty creates an international bureaucracy with a charter that includes a carte blanche to pursue additional measures in support of nuclear disarmament. (p. 23)
"The Executive Council comprises 51 member states, each of which is elected to the council by the Conference of All the States parties (all states that are party to the treaty)The treaty does not guarantee the United States a seat. Conceivably unforeseen political events may someday deny U.S. representation. (p.24)
"The danger exists that the Executive Council may use its power to conclude arrangements that have significant political or economic repercussions, or both, and that would legally bind the United States ­ all without the approval of Congress. Providing such power to an international organization is unprecedented. (p.24)
it is possible that the Executive Council will use its authority to pursue additional steps toward disarmament, including measures unrelated to nuclear testing. By funding the CTBT organization, the United States would be financing an international bureaucracy with a charter that includes responsibility for pressuring the Unites States to give up its nuclear deterrent.
The above statements can only be described as "off the deep end" and "over the top."
First of all, members of the Executive Council are designated by their regional groupings on the basis of objective criteria and rotation. The North American and Western European Group, which includes the United States, has ten seats on the Council. Based on the objective criteria, as well the composition of the regional group, the U.S. is confident of continuing membership.
The notion that the CTBT Executive Council has acquired unprecedented and extraordinary powers to conclude agreements is fanciful. Every EC implementing a treaty can enter into agreements. How else would the treaty organization be able to contract for goods and services, transport, communications, data processing, install and upgrade monitoring stations in foreign countries, hire personnel, and so on?
Where is Public Opinion on the CTBT?
Based on a selective set of polling data from a 1997 University of New Mexico public opinion survey (commissioned by Sandia National Laboratory), Kathleen Bailey claims that there is strong support for the CTBT, because polling "respondents were not told that the treaty would be unverifiable or that confidence and reliability of the U.S. stockpile would decline without testing." She suggests that if the public were presented with the argument that the treaty is unverifiable and that confidence in the U.S. stockpile will decline without testing, the public opposition to the CTBT would "probably substantially increase."
Bailey's analysis is misleading and incomplete in several respects:
1. Bailey ignores a large body of recent and historical polling data indicating that voters of all political affiliations overwhelmingly support the CTBT, no matter how the question is asked. These results reinforce the UNM survey's finding that 73% of the public support the CTBT:
* An overwhelming majority of American voters want the Senate to approve the Comprehensive Test Ban Treaty (CTBT), according to bipartisan public opinion surveys conducted in six states by a bipartisan polling team in June 1998.(12) When asked -- "Do you think the U.S. Senate should approve a Treaty with 140 other countries that would prohibit underground nuclear weapons explosions worldwide?" -- approximately 8 out of every 10 voters say the treaty should be approved.
* Support for the CTBT Cuts Across All Demographic and Partisan Lines. In all states and in two separate national surveys (The Mellman Group, May 1998 and September 1997), Republican, Democratic, and independent voters overwhelmingly support Senate approval of the CTBT. In no state does support for the test ban from Republican, Democratic, or independent voters drop below 70%. Support for the test ban treaty remains strong among all demographic groups, including veterans and voters with family members who have served in the military.
* Since India and Pakistan's nuclear tests in May, public support for a nuclear test ban treaty appears to be growing. According to the June 1998 Mellman-Wirthlin state polls, support for Senate approval of the CTBT is higher in each of the six states (Kansas: 79% approve, 14% disapprove; Nebraska: 83% approve, 13% disapprove; Oregon: 86% approve, 10% disapprove; Tennessee: 78% approve, 19% disapprove; and Utah: 83% approve; 14% disapprove) than it is nationwide (73% approve, 16% disapprove, according to the May 1998 poll, which was conducted days after India's tests, but before Pakistan's).
* The Indian and Pakistani tests have penetrated the public's consciousness: at least 8 out of every 10 voters in each state surveyed say they have heard about the tests and equal numbers say the tests pose a "serious threat to international security." Approximately 8 out of every ten respondents who heard about the South Asian tests supported the CTBT.(13)
* American public support has remained consistently high over the decades. The results of the latest opinion surveys are consistent with those from 11 nationwide polls on the test ban conducted since 1957, when President Eisenhower first sought a nuclear test ban. While poll questions have varied somewhat over the years, support has ranged only from 61%-85%.(14)


With such consistent support for the CTBT, it is highly unlikely that the public will change its view as a consequence of so-called "information" from test ban opponents. The public deserves greater credit and respect for its consistent support for a treaty to end all nuclear testing.
2. Contrary to Bailey's assertions, when survey respondents are presented with more detailed arguments for and against the CTBT, support remains very strong.
When given the choice between two possible candidates for Senate -- one who supports the CTBT and the other who opposes the CTBT -- most voters solidly prefer a candidate who supports the CTBT over one who opposes the treaty. According to the results of the June 1998 Mellman-Wirthlin state surveys, 69-73% of respondents say they would support the candidate who supports the CTBT, 20-24% would support the candidate who opposes the CTBT. In this question, respondents heard descriptions of two hypothetical candidates for Senate, including arguments typically used for and against the treaty:
Candidate A (Supports CTBT) says that the U.S. Senate should ratify the Comprehensive Test Ban Treaty, because the treaty is an important step in stopping the spread of nuclear weapons worldwide. Candidate A says the treaty would outlaw nuclear testing, improve our ability to detect nuclear tests and would prevent other countries from developing reliable nuclear weapons. Candidate A says the U.S. has conducted over 1000 nuclear test and does not need further nuclear tests to maintain our nuclear arsenal. Candidate A says the U.S. should be a leader and ratify the Treaty if we expect other nations to stop their nuclear weapons testing.
Candidate B (Opposes CTBT) says that he U.S. Senate should not ratify the Comprehensive Test Ban Treaty because the treaty does not stop other countries from acquiring nuclear weapons. Candidate B says that because compliance with the treaty cannot be verified, ratifying the treaty would prevent the U.S. from conducting tests to maintain and improve our nuclear arsenal while other countries seeking nuclear arms could continue to conduct secret tests.
3. While the UNM survey finds that a majority of the public believes that it is "important" to retain U.S. nuclear weapons, Bailey fails to note that a majority of UNM respondents also oppose increases in "spending for developing and testing new nuclear weapons" (61% say such spending should be decreased, 15% say it should stay the same, 23% say it should be increased).(15) This essentially represents a rejection of her alternative to the CTBT -- allocate funds for a resumption of U.S. testing.
These results are indicative of other survey findings that demonstrate that most Americans believe that nuclear weapons have improved U.S. national security, but that nuclear weapons dangers should be reduced when and where possible. In a September 1997 national public opinion survey conducted by The Mellman Group for the Henry L. Stimson Center, 56% of respondents "feel that nuclear weapons improve our national security," 33% "feel that nuclear weapons threaten our national security," and 12% don't know. At the same time, 80% of all respondents "support eliminating all nuclear weapons from all countries in the world through a verifiable enforceable agreement," 17% oppose, 3% don't know.(16)
End Notes
1. For a detailed discussion of this issue, see R. E. Kidder, "Maintaining the U.S. Stockpile of Nuclear Weapons During a Low-Threshold or Comprehensive Test Ban," UCRL-53820, Lawrence Livermore National Laboratory, October 1987, and Michael C. Axelrod, "A Statistical Analysis of the Accuracy of the Measurement and Prediction of the Yields of U.S. Nuclear Weapons Tests, LLNL, Livermore, CA., UCID-21186, 24 September 1987. The Kidder study exists in both classified and unclassified versions. The Axelrod study remains classified.
2. Enclosure 1 to letter to the Honorable Jon Kyl, United States Senate, from S. S. Hecker, Director, Los Alamos, September 24, 1997, response to Question 1.
3. Hecker to Kyl, op. cit., response to Question 7.
4. Ibid., response to Question 2.
5. Ibid., partial response to Question 5.
6. Ibid., partial response to Question 15.
7. "Sandia's Answers to CTBT Questions from Senator Kyl," October 22, 1997, enclosure to letter to MR. Alex Flint, Majority Clerk, Senate Appropriations Committee, November 5, 1997, response to Question 1.
8. Kent Johnson et al., "Stockpile Surveillance: Past and Future," SAND 95-2751/UC-700, January 1996, pages 5 and 8 and Figures 4 and 10.
9. Robinson to Flint, op. cit., response to Question 2.
10. A requirement to conduct all such dynamic experiments with fissile materials above ground in suitable containment vessels with a given tensile strength, would place a much lower bound on the maximum yield from such experiments, and such vessels could be easily inspected after the shot for evidence of fission products indicating that a prohibited prompt critical chain reaction had been achieved.
11. Hecker to Kyl, op. cit., response to Question 13.
12.. The state polls were commissioned by the Coalition to Reduce Nuclear Dangers, a non-partisan alliance of 17 of the nation's leading arms control groups. The results are based on the findings of opinion surveys of registered voters in six states conducted by Wirthlin Worldwide, a Republican polling firm, and a Democratic firm, The Mellman Group, from June 8-24. The statistical margin of error is plus or minus 3.5 to 4.9 percentage points. National opinion surveys were conducted in May 1998 and September 1997 by The Mellman Group. Complete polling results and survey questions are available on the Coalition's Web Site http://www.crnd.org
13. Presentation of Findings from Statewide Surveys in Kansas, Nebraska, Oregon, Tennessee and Utah, for the Coalition to Reduce Nuclear Dangers, The Mellman Group, Inc. and Wirthlin Worldwide, July 1998. Available at http://www.clw.org/coalition/combo.htm
14. "Public Support for a Nuclear Test Ban Treaty Remains High," polling results on public attitudes on the CTBT since 1957. Coalition Issue Brief, September 26, 1997, available at http://www.clw.org/coalition/bckgrpol.htm
15. Public Perspectives on Nuclear Security, UNM Institute of Public Policy, The University of New Mexico, June 1998, page 89.
16. Public Attitudes on Nuclear Weapons, The Henry L. Stimson Center, September 1997, page 22-24.
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