Senior DRDO scientist K Santhanam on Thursday reiterated that there was no question about backing away from his assertion that the 1998 Pokhran II nuclear tests were not fully successful, while the Chief of Naval Staff, Admiral Sureesh Mehta, said the tests conducted eleven years ago were adequate.
Santhanam said that he stood by what he had said. Admiral Mehta, who was addressing his farewell press conference in New Delhi, said: "The tests were adequate. We believe whatever the scientists tell us. The scientists said the tests were enough and tested. We believe the scientists, as they provide us with nuclear capability."
Admiral Mehta's statement came even as the defence ministry and former National Security Adviser Brajesh Mishra dismissed Santhanam's statement, adding that India has a meaningful number of nuclear weapons and an effective delivery system to go with it.
Sources in the ministry told a channel that India has a nuclear deterrent that is adequate for its security.
Santhanam, who was director for 1998 test site preparations and worked directly under Dr. A P J Abdul Kalam when he was the scientific adviser to the then Defence Minister, told said the yield of thermonuclear explosions was actually much below expectations and the tests were perhaps more a fizzle rather than a big bang.
In nuclear parlance, a test is described as a fizzle when it fails to meet the desired yield. Santhanam said the yield for the thermonuclear test, or hydrogen bomb in popular usage, was much lower than what was claimed. Santhanam also said that given this fact, India should not rush into signing the CTBT.
He emphasized 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.
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.
Sources claim that Santhanam had admitted that the test was a fizzle during a discussion on CTBT organized by IDSA. India conducted five nuclear tests at the Pokhran test range. Three of them were conducted on May 11 and two on May 13, 1998.
Rajagopala Chidambaram headed the team, which conducted tests, and the device was developed at the Defence Research and Development Organization's Ballistics Research Laboratory.