Pokhran-II: An H-bomb disaster

Several articles have been written in recent weeks, on the Pokhran tests of 1998 and, in the wake of disclosures about the failure of the test of the thermo-nuclear (TN, or hydrogen bomb) device, the need for further testing. Some of these articles have argued that technical information published by the DAE and the BARC does not show that Pokhran-II was unsuccessful; and that there are compelling arguments against resuming H-bomb testing, even if the TN test was a failure.

BARC is quoted as saying that the TN device's yield was "consistent with" its original estimate of 50 + 10 kilotons (kT) for the two main tests conducted on May 11, 1998, viz. a 45 kT (TN) device and a 15 kT A-bomb which were exploded simultaneously.

BARC has also argued that it employed different techniques to estimate the device yield (power output), and that the post-shot Radio-Chemical Method (RCM) used to arrive at the above figure was considered the most accurate for measuring device yields. However, according to the former director of BARC's radio-chemistry division, he had measured the yield of India's first nuclear device in 1974 (P1) using the Mass Spectrometry method, internationally accepted as even more accurate than the officially tom-tommed RCM. It is also far less sensitive to the major weakness of the RCM method: If a sample is taken even slightly off the geometric centre of the core cavity (the heart of the nuclear weapon), the yield estimate can be way out from correct value. That was the principal reason why Raja Ramanna, the 'Father of our Nuclear Weapon Programme,' insisted on using the MS method for yield estimation in 1974. If the MS method was used in P-2 also, the results should be made public. If it was not used, why not?

Both the A-bomb 'trigger' and the main H-bomb produce neutrons. However, H-bombs produce more neutrons than A-bombs. This leads to considerably larger amounts of two artificially created radio-isotopes--Manganese 54 and Sodium 22--being produced by the TN device than the A-bomb. This higher ratio of Manganese 54 to Sodium 22 in the H-bomb explosion gives an 'idea' of the A-vs H-bomb/device yields (no numbers, only an "idea"), it has been argued.

The absolute values of this higher ratio have been withheld for 'obvious' reasons, says BARC conveniently. However, a 'fizzled' TN device also produces 'copious amounts' of these isotopes. Moreover, the mere presence of these isotopes is not a quantitative yield measure; at best it is only a qualitative indicator. The source of many of the assertions is an article in the July 1999 issue of BARC's in-house newsletter — not a peer-reviewed scientific journal. How many people in India, let alone internationally, are even aware of such a newsletter, or read it, even sporadically?

But there are more serious problems with BARC's assertions. Crucially, BARC claims the A-bomb yield was only 15 kT when its collaborator in P-2, the Defence Research and Development Organisation, and leading nuclear weapons laboratories worldwide, have rated it at 20–25 kT. Moreover, the hi-tech ARC — which is totally independent of both BARC and DRDO—with its very large seismic array that is 10-15 per cent more sensitive and accurate than DRDO's, (and far superior to the 30-year-old BARC array at Gauribidanur in Karnataka) measured all seismic signals from all P-2 tests. The highly sophisticated measurements and calculations of ARC scientists indicated a maximum TN device yield at only 20 kT. It is no wonder that the failed TN device has not been weaponised, 11 years after P-2, and India is absolutely naked today before China's H-bombs!

A 15 kT device could not have produced a 25-metre diameter crater as had occurred. What's more interesting is that, what BARC claims was a 45 kT H-bomb—that is supposedly thrice as powerful—produced no crater at all! Commonsensically, a genuine 45 kT TN device should have produced a gigantic crater. To get around this difficulty, BARC argues that if the shaft (in which the TN device is placed) is deep "enough", there will only be upheaval within the shaft, but no crater will be created. However, the shaft containing the TN device was only 20 metres deeper than the shaft for the A-bomb. Such a small difference cannot "explain" the fact that there was no crater at all.

Had the TN test really worked, the 120-metre deep shaft at the bottom of which the TN device was placed would have been totally destroyed, and its deepest portions even vapourised. There would, in addition, have been enormous surface damage. Most tellingly, the massive two-tonne, eight-meter high tripod ("A-frame") astride the shaft's mouth with a complex set of winches and pullies connected to a lift-like container to lower and raise personnel, equipment and materials to and from the shaft's bottom, would have been totally destroyed. But the A-frame was totally intact after the TN device test. How can this hard, visual evidence be ignored?

Some experts have argued that the damage that even a 25 kT A-bomb can cause to enemy city targets with large populations would be unacceptable to any adversary, and so, such A-bombs would be enough for us to deter even China, which has already deployed 200 H- bombs of 3.3-5 megaton yields each--200 times more powerful than what we have. Around 50 of these are in Tibet targeting us. It is astonishing to see the same people who argued vociferously for decades that H-bombs were central to our Credible Minimum Deterrent, suddenly do a volte-face and say A-bombs (which, for technical reasons, cannot be made to have yields more than 80 kT) are enough! Why?

China would be undeterred by our A-bomb arsenal of the yields indicated above. So we reiterate our considered view-- shared by the majority of our nuclear scientists, strategic analysts and, above all, our military--that a solely A-bomb arsenal is inadequate as a deterrent against China. Otherwise, why did four prime ministers want a TN device (H-bomb) and why did the then Prime Minister Vajpayee and his National Security Advisor Brajesh Mishra direct and insist with the BARC-DRDO leadership — Kalam, Chidambaram, Santhanam and Kakodkar--that at least one P-2 test must be of a TN device?

The current controversy over the failure of India's sole H-bomb test of P-2 is only the latest case in a long history of DAE and BARC being "highly economical" with the truth, and using such "economy" to protect themselves from public criticism of major failures in large numbers of programmes and projects. Failures have been screened from the public gaze on the grounds of 'nwarranted secrecy; worse, DAE has made a huge effort to hide the facts from not only successive Parliaments and the people but even from successive governments, causing incalculable damage to our nuclear weapon and power programmes and to national security.

K Santhanam is a former chief adviser (Technologies), DRDO, and programme director, Pokhran II.

Ashok Parthasarathi is a former S&T adviser to late Prime Minister Indira Gandhi and Secretary of several scientific departments.