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Disarmament Diplomacy

Issue No. 40, September - October 1999


Verifying the CTBT: Responses to Republican Criticisms

By Oliver Meier


During the CTBT ratification debate in the US Senate opponents of the Treaty used two key arguments before the proposed bill was defeated on October 13, 1999. Firstly, critics argued that ending nuclear testing could affect the safety and reliability of the US nuclear stockpile. Secondly, they maintained that an international ban on nuclear testing would not be verifiable. "Militarily significant" tests could be conducted "with little or no risk of detection", according to one Senate Treaty opponent.1 While the US would not be able to test, went another argument, "rogue" states could secretly develop - or improve - nuclear weapons, thus ultimately threatening US security.

These arguments about verifiability, however, add nothing new to the debate about the CTBT. At best, they are misperceptions about the Treaty's intentions. At worst, they represent deliberate attempts to discredit the CTBT. However, if US ratification is to be achieved it will be essential to consistently and continuously refute false allegations made against the Treaty's verification system.

What is the Capability of the CTBT Verification System? - Sub-Kiloton Tests

The International Monitoring System (IMS) consists of 321 stations and 16 radionuclide laboratories located around the world, and forms the core of the Treaty's verification mechanism. The system, which is due to be ready when the Treaty enters into force, will also be supplemented by a regime for on-site inspections. Despite some political, legal and technical problems the Provisional Technical Secretariat (PTS) has made steady progress in setting up the IMS.2 Approximately one-third of all the stations are already reporting to the International Data Center (IDC) in Vienna, which will be fully functional next January. Based on current trends the entire system will be operational by 2003, given continued US support.3

While it is true that there is no such thing as a perfect verification system and that undetected cheating is possible in any arms control agreement, the Treaty's verification system will considerably increase the international community's ability to verify compliance with the CTBT. For any potential violator, it will considerably increase the risk of being detected and the cost of attempting to cheat.

Some in the US remain apparently unconvinced about verifiability. On September 8, 1999, US intelligence agencies detected two seismic events near the former Russian nuclear test site at Novaya Zemlya. US experts were allegedly unable to determine the nature of these events. Unnamed US defence officials later stated that these events looked like "a covert nuclear test".4 Critics of the Treaty used this incident as proof that the CTBT is not verifiable. During the same month, a CIA report was released which concluded that the IMS cannot reliably detect very small nuclear tests, and that this "grey area" provides an opportunity for cheating.5 Moreover, the CIA "concluded that [the US] cannot monitor low-level nuclear tests by Russia precisely enough to ensure compliance".6

The Treaty outlaws any nuclear explosion, regardless of yield. The IMS was designed to guarantee the detection and location of explosions down to one kiloton, but the Treaty negotiations clearly reflect recognition that the synergistic relationship between the different monitoring technologies would ensure actual detection and location capabilities well below one kiloton.

Therefore, a determined proliferator could by no means be certain that a sub-kiloton test would go undetected. The IMS has already proven that it is capable of detecting such very small tests with a yield of less than one kiloton, under some circumstances. A test explosion using 0.1 kiloton (100 tonnes) of conventional chemical explosives, conducted in Kazakhstan in August 1998, was detected and located by nine IMS stations in Africa, Asia, Australia, Europe and North America.7 All four monitoring technologies (seismic, infrasound, hydroacoustic and radionuclide) have proven to be much more capable than anticipated, and monitoring technologies are being continuously improved and updated while the IMS is being set up. The combined effects of these technologies are already resulting in synergies, which will increase the system's capability to monitor compliance.

In addition, the Treaty contains an elaborate on-site inspection mechanism in case any ambiguity about an event remains unresolved. This mechanism, however, can only be applied if the Treaty enters into force. From this perspective, failing to ratify the Treaty is a self-defeating policy for the US Senate: it denies the United States - and other countries - the ability to check on-site for evidence of Treaty violations at suspected nuclear test sites.

Muddying the Verification Issue:

Sub-Critical Tests

Further confusion was added to the debate about verifiability when a Clinton Administration official suggested that the seismic event detected at Novaya Zemlya on September 8, 1999, might have been a Russian sub-critical test.8 Sub-critical nuclear tests are not explicitly banned under the Treaty but they may be detected by remote monitoring means, such as satellites or signal intelligence. Sub-critical experiments are not "real" nuclear explosions, since no self-sustaining fission reaction takes place, although small quantities of fissile materials are present. Instead, conventional explosions are used to determine how nuclear and non-nuclear materials perform under conditions similar to those in nuclear warheads. These tests are used to advance knowledge about nuclear designs. Russia and the United States maintain that sub-critical tests are necessary to guarantee the safety and reliability of their nuclear stockpiles.

During the CTBT negotiations many non-nuclear weapon states tried to strengthen the disarmament aspects of the Treaty by proposing stricter limits on sub-critical tests or other types of experiments that would assist in nuclear arms modernisation. These attempts failed.9 A $US 4 billion Stockpile Stewardship Program, including sub-critical tests, was the price the Clinton Administration paid in 1996 to gain the support of the US nuclear weapons complex for US signature of the CTBT. With this money, the weapons laboratory directors repeatedly testified they were "confident that a fully supported and sustained stockpile stewardship program [would] enable [them] to continue to maintain America's nuclear deterrent without nuclear testing".10 However, during the Senate debate on ratification the directors of all three major nuclear weapons laboratories somewhat revised their position and testified that they could not guarantee the long-term safety and reliability of the US nuclear stockpile under a CTBT. These attempts to discredit the Treaty may have been motivated by the wish to gain additional funding - or by hopes of resuming nuclear testing.11

Moscow reacted to the most recent CIA allegations by denying that any nuclear test had taken place at Novaya Zemlya and stating that it had not conducted any sub-critical experiments in 1999.12 Russia's Minister of Atomic Energy, Yevgeniy Adamov, also pointed out that Russia - like the United States - has a sub-critical testing programme which is supposed to ensure the safety and reliability of nuclear weapons and which is not explicitly banned by the Treaty.

While the IMS could not be expected to detect the small conventional explosions used in sub-critical tests, it might detect a sub-critical test that had gone unintentionally critical (or what US nuclear weapon scientists call the "whoops" factor). There are a number of ways to alleviate concerns about sub-critical testing, which is prone to being misinterpreted as an attempt to evade the Treaty. The United States and Russia - as well as other nuclear-armed nations that have sub-critical programmes - could and should be more transparent about these programmes. While the US does, at least, announce the dates of its sub-critical tests, it does not allow any observers at its test site in Nevada, where the sub-critical tests are usually conducted underground. Russia does not even announce the date of tests. The US Energy Secretary, Bill Richardson, has offered talks with Russia about bilateral transparency measures, such as reciprocal visits to their test sites and 24 hours pre-notification of sub-critical tests.13 While such measures would not solve the underlying problems caused by sub-critical testing, they would help to alleviate concerns that they may actually be low-yield nuclear tests in violation of the Treaty. By inviting representatives of the CTBT Organisation (CTBTO) to observe sub-critical tests, other states could also be assured about their nature and purpose.

The Treaty does not impede any bilateral transparency measures. Nor does it preclude the United States from using national technical means to reassure itself that no nuclear explosions are being conducted. But the Treaty's multilateral verification system would certainly augment the United States' national monitoring effort. Past events have shown that there are considerable gaps in US capabilities to detect nuclear tests and preparations for such tests. The US was caught off-guard, for example, by the Indian test series of May 1998. When an earthquake in the sea off Novaya Zemlya took place in August 1997, the United States mistakenly accused Russia of having conducted a nuclear test. The facts were later clarified using non-US seismic stations.14

Maintaining Support for the CTBTO

It will remain important to correct false allegations about the purpose and capability of the Treaty's verification system if the next ratification debate in the US Senate is to be won. Clearly, some senators who voted against ratification were misinformed about the scope and capability of the Treaty's monitoring system. But others, opposed to the CTBT in principle, did not want to listen and contrived arguments about non-verifiability to block ratification of the Treaty. When a high-ranking delegation of Princeton physicists visited Washington at the beginning of October - more than a week before the final Senate vote - they tried to identify and convince undecided Senators to support the CTBT, but they "couldn't find any". One of the visitors, Massachusetts Institute of Technology (MIT) Professor Frank von Hippel, said he came to realise that "the result was already stitched up".15

The United States should demonstrate its continued support for the CTBT by assisting the work being done in Vienna to set up the global monitoring system. Until the US Senate votes again on ratification of the Treaty, the US should not only continue to pay its share of the budget of the Preparatory Commission (PrepCom) charged with implementing the verification system - which it is obliged to do as a signatory state - but it should also continue its voluntary technical co-operation that has been so important in developing and implementing the Treaty's verification system. Failure to do so would result in further delays in setting up the IMS and call into question its future.

But completion of the verification system does not depend on the US alone. Both China and Russia reacted to the US Senate vote by pledging to continue national ratification procedures. Whether or not these statements reflect an attempt to take the moral high ground, or are indications of a serious commitment to the CTBT, will be measured by the support these states give to the PrepCom's continuing work. Finally, Ambassador Wolfgang Hoffmann, Executive Secretary of the PrepCom, has already made clear that the PTS "will continue to build up the global verification regime, which will take several more years", and hopes "that during this time the United States will see its way to ratifying the CTBT".16

Notes & References

1. Senator Wayne Allard quoted in "Clinton Asks Senate to Delay Test Ban Vote", Helen Dewar, Washington Post, October 9, 1999.

2. For a detailed account of progress in setting up the IMS see "Not Quite Ready and Waiting: The CTBT Verification System", Trevor Findlay and Oliver Meier, VERTIC Briefing Paper 99/3. (London, Verification Research, Training and Information Centre, September 1999).

3. Press Conference with Ambassador Wolfgang Hoffmann, October 8, 1999, Vienna. 4. "Russians May Have Tested Nuclear Device Underground", Bill Gertz, Washington Times, September 15, 1999.

5. "CIA Admits Test-Ban Shortcomings", Robert Suro, International Herald Tribune, October 4, 1999.

6. "US Senate ignores scientific advice in failing to ratify test ban treaty", Colin Macilwain, p. 735, Nature 401, 6755, October 21, 1999.

7. "Speech by the Executive Secretary of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) to the Conference on Facilitating the Entry Into Force of the Comprehensive Nuclear-Test-Ban Treaty", Vienna, October 6, 1999.

8. "Of Testing and Treaties", Walter Pincus, International Herald Tribune, October 9-10, 1999.

9. See "Ending Nuclear Weapon Testing: Getting and Keeping the CTBT", Rebecca Johnson, pp. 23-42, Verification 1997, The VERTIC Yearbook, [Ed Richard Guthrie], Boulder, Colorado and Oxford, UK: Westview Press, 1997.

10. Testimony of June 1999 before Congress, quoted in "Nuclear Arsenal is 'Safe and Reliable' Under Test Ban Treaty: U.S. Doesn't Need to Test -- But Others Do Need Tests to Improve Their Arsenals", Coalition to Reduce Nuclear Dangers, Press Release, Washington, D.C., October 11, 1999.

11. "US Senate ignores scientific advice in failing to ratify test ban treaty", Colin Macilwain, Nature 401, 6755, October 21, 1999.

12. PPNN Newsbrief, p. 3, Number 47, 3rd Quarter 1999.

13. "U.S. And Russia To Seek New Ways To Monitor Nuclear Test Ban Pact", Michael R. Gordon and Judith Miller, New York Times, October 4, 1999.

14. See CTBT Verification related case studies of three recent events: Novaya Zemlya, India and Pakistan, Department of Foreign Affairs and International Trade, Canada, December 1998.

15. "US Senate ignores scientific advice in failing to ratify test ban treaty", Colin Macilwain, p. 735, Nature 401, 6755, October 21, 1999.

16. "Statement on the United States Senate Vote by Wolfgang Hoffmann, Executive Secretary of the CTBTO PrepCom", Press Release, CTBTO PrepCom, Vienna, October 14, 1999.

Oliver Meier is Arms Control and Disarmament Researcher with the Verification Research, Training and Information Centre (VERTIC) in London.

© 1999 The Acronym Institute.

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