The 1998 Pokhran II nuclear tests might have been far from the success they have been claimed to be. The yield of the thermonuclear explosions was actually much below expectations and the tests were perhaps more a fizzle rather than a big bang. (
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The controversy over the yield of the tests, previously questioned by foreign agencies, has been given a fresh lease of life with K Santhanam, senior scientist and DRDO representative at Pokhran II, admitting for the first time that the only thermonuclear device tested was a "fizzle". In nuclear parlance, a test is described as a fizzle when it fails to meet the desired yield.
Santhanam, who was director for 1998 test site preparations, told TOI on Monday that the yield for the thermonuclear test, or hydrogen bomb in popular usage, was much lower than what was claimed. Santhanam, who was DRDO's chief advisor, could well have opened up the debate on whether or not India should sign CTBT as claims that India has all the data required and can manage with simulations is bound to be called into question.
``Based upon the seismic measurements and expert opinion from world over, it is clear that the yield in the thermonuclear device test was much lower than what was claimed. I think it is well documented and that is why I assert that India should not rush into signing the CTBT,'' Santhanam told TOI on Wednesday.
He emphasised the need for India to conduct more tests to improve its nuclear weapon programme. The test was said to have yielded 45 kilotons (KT) but was challenged by western experts who said it was not more than 20 KT.
The exact yield of the thermonuclear explosion is important as during the heated debate on the India- US nuclear deal, it was strenuously argued by the government's top scientists that no more tests were required for the weapons programme. It was said the disincentives the nuclear deal imposed on testing would not really matter as further tests were not required.
According to security expert Bharat Karnad, Santhanam's admission is remarkable because this is the first time a nuclear scientist and one closely associated with the 1998 tests has disavowed the government line. ``He is not just saying that India should not sign the CTBT, which I believe is completely against India's interests, but also that the 1998 thermonuclear device test was inadequate.
His saying this means that the government has to do something. Either you don't have a thermonuclear deterrent or prove that you have it, if you claim to have it,'' said Karnad. Sources said that Santhanam had admitted that the test was a fizzle during a discussion on CTBT organised by IDSA. Karnad also participated in the seminar. He told TOI that no country has succeeded in achieving targets with only its first test of a thermonuclear device.
``Two things are clear; that India should not sign CTBT and that it needs more thermonuclear device tests,'' said Santhanam. The yield of the thermonuclear device test in 1998 has led to much debate and while western experts have stated that it was not as claimed, BARC has maintained that it stands by its assessment. Indian scientists had claimed after the test that the thermonuclear device gave a total yield of 45 KT, 15 KT from the fission trigger and 30 KT from the fusion process and that the theoretical yield of the device (200 KT) was reduced to 45 KT in order to minimise seismic damage to villages near the test range.
British experts, however, later challenged the claims saying that the actual combined yield for the fission device and thermonuclear bomb was not more than 20 KT. Key Pokharan scientist R Chidambaram had described these reports as incorrect. He has also argued that computer simulations would be enough in future design.
Kalam defends Pokhran-II
Tribune News Service
A day after senior DRDO scientist K Santhanam created a stir by stating that India’s nuclear test in May 1998 at Pokhran was “not a total success”, his theory was debunked and discarded by defence experts, including former President APJ Abdul Kalam, who were in the know of the subject today. R Chidambaram, Principal Scientific Adviser to the Union government who had led the team of scientists during the 1998 nuclear tests, today dismissed as "absurd" the suggestion that Pokhran-II explosions did not yield the desired results. “There is no controversy over the yield of Pokhran-II nuclear tests,” he said.
Chidambaram, who was the chairman of the Department of Atomic Energy in 1998, was quoted by PTI news agency as saying: “If he (Santhanam) has any new scientific information which we are not aware of, it will be nice to have that data. He is a scientist and not a politician. Let him tell exactly what made him give that comment.” The results were published in detail in international journals and also took into account studies by several global experts, he added. Santhanam, who was the Defence Research and Development Organisation representative for Pokhran-II, had said “India should not sign the Comprehensive Test Ban Treaty (CTBT) as the country needed to carry out more tests as the thermonuclear tests in 1998 had failed to produce the desired results”. As per him, the yield of the tests could only be classified as a “fizzle” rather than big bang. In nuclear science, a fizzle is used when the outcome fails to meet the desired yield. Today as well, Santhanam, in a TV interview, stood by his comment.
Coming in defence of the test, former President APJ Abdul Kalam said the tests were successful and had generated the desired yield. After the test, he said, there was a detailed review based on two experimental results: seismic measurement close to the site and around; radioactive measurement of the material after post shot drill in the test site.“The tests at Pokhran were completely successful,” Kalam was quoted as saying by a news channel. Navy Chief Admiral Sureesh Mehta, while addressing his last press conference before retiring, said today: “India's nuclear deterrence capabilities are proven and capable enough” Official sources, when asked to comment on Santhanam's statement, said India's position on CTBT was well known, clear and consistent. “We will not subscribe to any treaty that is discriminatory in nature,” they said. Former national security adviser Brajesh Mishra, too, dismissed Santhanam’s statement by asserting that India had a “meaningful” number of nuclear weapons and an effective delivery system to go with it. He told a private television channel that the five nuclear tests conducted in May 1998 were successful.
“Dr APJ Abdul Kalam, then the scientific adviser to Defence Ministry, had announced that the 1998 nuclear tests conducted in Pokhran were successful. Dr Kalam’s version was credible enough, as Santhanam was working directly under him. That should set the record straight,” Mishra said Notably, the test, as per Indian scientists, is said to have yielded 45 kilotons (KT), a claim challenged by western experts who said it was not more than 20 KT.