Weaponisation & the CTBT

By P. R. Chari

A PRESS report quotes Dr. R. Chidambaram, Chairman, Atomic Energy Commission, affirming that of the five nuclear devices exploded in Pokhran two years ago, ``The 15 kiloton device was a weapon, which had been in the stockpile for several years. Others were weaponisable configurations''. The difference between a weapon and a ``weaponisable configuration'' lies in the fact that a host of other parameters, including the reaction of the device with the environment, has to be taken into account before a ``weaponisable configuration'' can be converted into a weapon. In other words, a ``weaponisable'' device could be designed or made into a weapon. The question now arises whether more tests are required to convert these ``weaponisable configurations'' into weapons.

The Joint Statement issued by the AEC Chairman and the Scientific Adviser to the Defence Minister shortly after the nuclear tests had stated that: ``The three tests conducted on May 11, 1998, were with a fission device with a yield of about 12 kt, a thermonuclear device with a yield of about 43 kt and a sub-kilo tonne device. On May 13, 1998, two more sub-kilo tonne nuclear tests were carried out.'' It further informed that: ``The tests... have provided critical data for the validation of our capability in the design of nuclear weapons of different yields for different delivery systems. These tests have significantly enhanced our capability in computer simulation of new designs and taken us to the stage of sub-critical experiments in the future, if considered necessary.'' This carefully-worded phraseology does not clarify whether more field tests would be required to fashion the devices tested at Pokhran, with reasonable confidence, into deliverable nuclear weapons.

This issue gains salience because several assertions have been made by Dr. Chidambaram, the scientific bureaucracy and the political leadership that India does not need to conduct more nuclear tests, since the data provided by Pokhran would allow proceeding towards weaponisation and deployment of nuclear weapons. Based on the advice of the nuclear- defence scientific community India had announced ``a voluntary moratorium on underground nuclear test explosions'' soon after the May 1998 tests. The Prime Minister also formalised India's position on the CTBT by assuring Parliament in December 1998 that, ``We are prepared to bring these discussion (on the CTBT) to a successful conclusion, so that the entry into force of the CTBT is not delayed beyond September 1999. We expect that other countries, as indicated in Article XIV of the CTBT, will adhere to this Treaty without conditions.

This assurance was indubitably in response to the communiques issued by the P-5 countries in Geneva and G-8 nations in London that were included in Security Council Resolution 1172 of June 6, 1998, after the Indo-Pakistan nuclear tests. They required India and Pakistan, in part, to ``conduct no further nuclear tests; (and) sign and ratify the Comprehensive Test Ban Treaty immediately and without conditions''. But an escape route was kept open with the Government's caveat that a national `consensus' was necessary before India could sign the CTBT.

The demarche that India enters the CTBT is included among the ``benchmarks'' being discussed within the continuing Strobe Talbott-Jaswant Singh dialogue. The failure of the U.S. Senate to ratify the CTBT has currently placed it on the backburner, gaining valuable breathing time for India. In the U.S. perception, however, it is important that India and Pakistan sign and ratify the CTBT, and great emphasis is being placed on this particular benchmark in official and non-official dialogues. The two motivations informing U.S. policy are obviously the need to corral the two South Asian adversaries into the CTBT, which would be a major incentive for other holdouts to join and ratify the Treaty, and ensure thereby its universalisation; and to stop further tests by India and Pakistan, this would mitigate the likelihood of a dangerous nuclear arms race ensuing between them.

The U.S. pressure upon both countries to sign and ratify the CTBT will persist till the end of the Clinton Administration. Whether the next administration will abandon this policy, is essentially a speculative question. The inescapable problem confronting India is whether to sign the CTBT at this juncture or conduct more tests to operationalise its nuclear posture.

This issue can be approached from a different perspective. How far can India proceed without further nuclear tests? Mr. Richard Garwin, a highly regarded former consultant to Los Alamos National Laboratory in the U.S., wrote in the November-December 1997 issue of Arms Control Today that a non-nuclear-weapon state could: ``With reasonable confidence build a gun barrel-type fission weapon using uranium-235, and a first-generation implosion `weapon' with greater difficulty and less confidence using weapons grade uranium or plutonium. Somewhat greater uncertainty and difficulty would be associated with using reprocessed plutonium from commercial reactor-grade spent fuel. Increasing uncertainty would arise if more advanced implosion systems were to be produced using less fissile material that the basic solid-sphere design. Still greater uncertainty would arise if a `boosted' fission weapon was to be designed and manufactured without testing. Finally, very little confidence could be placed in the efficacy of a two-stage thermonuclear weapon that had never been tested.''

Great scepticism has attached to our scientists' claims that a thermonuclear device had been tested in Pokhran. Analysis of seismic signals endorsed beliefs that a ``boosted fission'' device had been tested and not a two-stage thermonuclear device; the Atomic Energy Commission angrily refuted this. Dr. Chidambaram is now on record stating that a ``fusion-boosting fission device'' had constituted the primary stage of this device, followed by a fusion device in the secondary stage. Only its aggregate yield viz. 45 kt was made public, but not the separate yields of the two stages for reasons, no doubt, of national security. Dr. Iyengar has calculated the yield of the secondary thermonuclear stage to be around 20 kt, which, he believes, requires the device to be improved ``to get greater efficiency and smaller size. This would require design changes in the thermonuclear device, and further tests to validate the improved design.'' Even if one does not contest the affirmation that a two-stage thermonuclear device had, indeed, been tested in Pokhran, commonsense suggests that one test of such a complex system is not enough, and more tests are essential to validate the design to the satisfaction of the military and political leadership.

Why is the need for a credible thermonuclear device imperative? To cite Mr. Garwin again, in testimony before the U.S. Congress, ``even in the yield range accessible to fission weapons, thermonuclear weapons are attractive for their economy of fissile material, their compact size, and their improved safety.'' But, ``without nuclear tests of substantial yield, it is difficult to build compact and light fission weapons, and essentially impossible to have any confidence in a large-yield two-stage thermonuclear weapon.'' The capability no doubt exists currently to deploy 15-20 kt fission weapons. The need for thermonuclear weapons, however, is unavoidable if India is to deploy a nuclear triad as envisaged by the nuclear doctrine, which is moreover not country-specific but possesses an all-azimuth character. This would be impossible unless further tests are conducted, their number would depend on the sophistication required from the nuclear arsenal. In the current state of the game, India cannot be accepted as a de jure nuclear weapon state without amending the Nuclear Nonproliferation Treaty, which is a highly improbable possibility. Its claim to be de facto nuclear weapon status would be constrained by the inadequacies of its nuclear capability, noted above, all other recognised nuclear weapon powers premise their arsenals on thermonuclear weapons.

What then are India's narrowing options vis-a-vis the CTBT? It is to sign it without reserve, or sign it but not ratify the Treaty (it needs mention that the Vienna Convention on Treaties binds a country signing a Treaty to abide by its provisions thereafter), continue the present standstill policy of honouring its declared moratorium but continue laboratory work to refine the warheads, or resume testing and then enter the CTBT. Obviously, each of these options has its attendant costs and benefits. The process of hammering out a national consensus cannot shirk addressing these issues.

(The writer is Director, Institute of Peace and Conflict Studies, New Delhi).

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