The recent assertion by K. Santhanam, formerly with the Defence Research and Development Organisation and a key figure who coordinated the Shakti series of nuclear tests, that the thermonuclear bomb tested on 11 May 1998 was a fizzle and failed to reach the desired yield has raised questions about the reliability of India’s nuclear arsenal.
It has also renewed the debate on whether it is essential to conduct further nuclear tests or not to ensure India’s thermonuclear weapon will work as expected.
It is the wrong question to ask. The real question is: does India really need a thermonuclear weapon to ensure its credible minimum nuclear deterrent?
Before addressing this question, it is important to understand what a thermo- nuclear weapon is and how it is different from a nuclear weapon. It is equally crucial to understand the factors motivating countries to acquire such weapons.
So, what is a thermo- nuclear bomb? A nuclear bomb, which is triggered by conventional explosives to create a chain reaction from the critical mass of fissile material, derives its explosive power by splitting (fissioning) atoms of the heavy elements uranium (U235) and plutonium (Pu239). That is why a nuclear bomb is known as a fission weapon.
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In contrast, a thermonuclear bomb is also called a fusion bomb or a hydrogen bomb because the bomb derives its explosive power from fusing atoms of the light element hydrogen, such as tritium (3H) or deuterium (2H or D). Since fusion can only be achieved at extremely high temperatures of around 10,000 degrees Celsius (such as those found in the sun), hydrogen bombs are triggered by a fission bomb, which is the only source capable of producing these high temperatures on earth. Because of the high temperatures needed for fusion, the hydrogen bomb, or H-bomb, is also known as a thermonuclear bomb.
The H-bomb is a two-stage weapon where a fission nuclear bomb serves as the primary detonator, which then compresses and triggers a fusion fuel secondary, leading to a massive explosion. In theory, an H-bomb can produce unlimited destructive power. The biggest bomb tested by the Soviet Union produced 50 megaton of explosive power—nearly 3,000 times more destructive power than the bomb dropped on Hiroshima.
The H-bomb is also the most complex of all nuclear weapons to develop and this is why no country has been able to perfect it in a single shot. It would have been a miracle or a technological fluke if the first ever test of an Indian H-bomb had worked flawlessly.
The challenges of building an H-bomb notwithstanding, there are at least three reasons why countries seek to acquire this deadliest of all nuclear weapons. First, thermonuclear weapons provide more bang for the buck in that the fissile material used to make a fission bomb can be made a hundred or thousand times more lethal by adding a secondary or a second-stage fusion at little extra cost.
This might be particularly appealing to countries that have limited fissile material and feel the need to develop weapons with yield in the megatons. Although this might be attractive to a country such as India that perhaps has limited fissile material for all its strategic nuclear needs, it is a huge gamble to depend on a design that has not worked as expected. It would be far more prudent to use the material in a boosted weapon, which has already been successfully tested in 1998.
Secondly, countries that adhere to a counter-force strategy, which seeks to attack and destroy the nuclear forces and related command and control capabilities of the other side in a decapitating first strike before these forces can be launched, will find the H-bomb attractive. The enormous destructive power of the H-bomb is particularly suitable for destroying the hardened underground nuclear missile silos and command and control centres.
However, for India, which has a declared no-first-use strategy and an implied second-strike, counter-city strategy (which calls for India to absorb the first nuclear strike and then retaliate against the vulnerable cities of the other side), the H-bomb is not particularly useful. Such massive destructive power is not necessary against unprotected cities, which are particularly vulnerable even to fission weapons.
Perhaps this is why the Indian Armed Forces, which have consistently asked for nuclear weapons, have never demanded the H-bomb. The outgoing navy chief and the chairman of the chiefs of staff committee, Admiral Sureesh Mehta, endorsed this when he categorically stated that India had already acquired a credible minimum nuclear deterrent, implying that an H-bomb was not essential for India’s strategic nuclear objectives.
The third reason why countries might seek the H-bomb is prestige. In fact, given the complexity of building the H-bomb, the history of this bomb is rife with stories about scientists and countries seeking this weapon to prove that they are as good, if not better, than scientists in other countries or even in their own nuclear establishments.
This debate is likely to remain alive and the reliability of India’s nuclear arsenal will be constantly questioned until the government firmly endorses the credibility of the arsenal by ruling out any further tests once and for all.
The best way for the Manmohan Singh government to end this debate and shut off the possibilities of future tests is to sign and ratify the comprehensive test ban treaty. Such a move would be even more courageous than signing the Indo-US nuclear deal or, indeed, carrying out more tests for a weapon that India does not really need. Will Singh show this courage of conviction?
W. Pal Sidhu is vice-president of programmes at the EastWest Institute, New York. His PhD thesis from Cambridge University was on The Development of India’s Nuclear Doctrine Since 1980. He writes on strategic affairs every fortnight. Your comments are welcome at firstname.lastname@example.org