I fully agree with K Santhanam that the single thermonuclear device we tested in 1998 did not produce anywhere near the expected design yield. I know this reliably, from multiple knowledgeable sources.
According to them, only 15 to 20 percent of the intended release of fusion energy was actually achieved. However, what happened is neither unusual nor was it a 'scientific failure' on the part of the Bhabha Atomic Research Centre/Defence Research and Development Organisation scientists.
All nations which have perfected fusion bombs have carried out several development tests, and no country has hit it perfect in their first test! Dr R Chidambaram and A P J Abdul Kalam should know this well, that they alone are not super-scientists!
But, as a nuclear engineer myself, I am appalled that a scientist of Dr Chidambaram's stature could claim that this solitary test was perfect and, for further fine-tuning of the design, we do not need any more tests, rather we could rely solely on computer simulations!
The establishment of a validated computer simulation model requires a reasonably large body of data to be obtained from a minimum set of well-structured tests, in each of which certain critical parameters are systematically altered. This is true not only for nuclear tests, but even for pharmaceutical or material development tests, etc. No extrapolation or improvement of the current faulty design can be done without more weapon tests.
Dr Chidambaram is an enormously gifted high-pressure physicist who was associated for years as a member of the weapons team led by Dr P K Iyengar. Dr Iyengar is truly considered to be the father of the Indian thermonuclear weapons development. Soon after the 1998 tests, Dr Iyengar himself has come out with scientific details to show that the thermonuclear device of 1998 did not function at all as per design or as expected.
Incidentally, Dr Kalam, who has also commented on the yield, is neither a nuclear scientist nor did he have any major role or contribution in the country's nuclear weapons development.
Certain DRDO labs and their specific groups have contributed, and the military establishment under Dr Kalam's overall guidance gave much of the logistical support at the test site. It is ridiculous to see the Indian media and many admirers of Dr Kalam dubbing him wrongly as the 'Father of the Nuclear Bomb'.
More pathetic is the spectacle of Dr Kalam silently taking the bow and indirectly accepting the accolades wrongly directed at him, when he is aware that it is really the qualified and experienced scientists in BARC like the late Dr Raja Ramanna, Dr Iyengar, Dr Chidambaram, Dr S K Sikka and others over the years who are to be applauded for this achievement.
It seems highly unethical of Dr Kalam to accept credit when he knows it does not belong to him. In the same vein, when it comes to contradicting Dr Santhanam's belated admission of the truth, Dr Kalam has neither the technical qualifications nor the direct participatory experience to technically comment on the veracity of the government position.
In summary, it is a fact that India has no proven capability today to design and deliver a thermonuclear warhead for the Indian armed forces.
Dr Kalam, who is contradicting Dr Santhanam's position, is neither a scientist who understands fusion physics or weapons design in depth, nor was he intimately involved in the device design or its post-test analysis. Dr Chidambaram in 1998 had taken the same government position as today, and being a part of the Prime Minister's Office, he cannot contradict it. Dr Kalam and DR Chidambaram have both gained a great deal personally in terms of official positions and awards, through their recognition as the 'great first-time developers' of the Indian fusion bomb, and they would not like this position of fame to be damaged.
In summary, the question before the country is: Do we need thermonuclear weapons as part of our arsenal for deterrence? If the answer is yes, India must conduct further tests, irrespective of any under-the-table promise that might have been given by the United Progressive Alliance government to the Americans that India will not conduct any more tests. But the government has to transparently and convincingly substantiate the reasons for not conducting any more tests, and that reason should not be linked to the Indo-US nuclear deal or the Nuclear Suppliers Group waiver getting into trouble if we undertake more tests.
Dr A Gopalakrishnan, former chairman of India's Atomic Energy Regulatory Board, made these observations in a letter to diplomat and rediff.com columnist T P Sreenivasan.