There are a number of issues that need to be taken note of and that seem to be lost in what is increasingly a war of personalities between scientists:
(1) Dr. Santhanam has claimed that the TN test achieved a yield of between 23-27 kilotons.
(2) If that statement is taken to be accurate - and let us assume that it is - that yield is substantially higher than that claimed by analysts in the West who using data and assumptions that were at times questionable suggested a much lower yield.
(3) Dr Santhanam in his op-ed piece claimed the deployment of 25 kiloton warheads on a wide scale.
(4) Subsequently he has said that India's deterrent consists only of 15 kiloton weapons - some consistency would be appreciated in this regard.
(5) What nobody has explained is why India has built missiles - with Santhanam himself in DRDO - with payloads of between 700 and 1500kg ?
(6) The other issue that has not been tackled is that of the primary stage of the TN device which has not been disputed as being a boosted-fission device and which, if Santhanam's figures are correct would have had to have a yield and produced a yield of between 15 and 17 kilotons.
(7) Taking Dr. Santhanam's words as being accurate some conclusions can immediately be drawn:
(a) India's weapons teams were not convinced of the TN test and did not weaponize any thermonuclear weapons
(b) India's deployed nuclear weapons weigh between 700kg and 1500kg - based on the Agni payloads
(c) Both fission and boosted-fission types that were tested worked.
(8) Admiral Suresh Mehta's words were very guarded:
"As far as we are concerned, scientists have given us a certain capability which is enough to provide requisite deterrence...the deterrent is tried and tested"
(9) No 15 kiloton or 25 kiloton fission or boosted fission device weighs 700-1500kg. At most the figures for those types will range between 170kg and 300kg with Indian design technology.
(10) Nobody - either critics or supporters - have considered the possibility of the scalability of either the fission or boosted-fission weapons/devices tested. This aspect of Indian weapons research in the last decade is what needs to be examined if one is to assess the Indian nuclear deterrent.
(11) The French MR31 120kiloton warhead used on their SSBS-S2 IRBM was a pure fission warhead weighed 700kg using about 25kg of weapons-grade plutonium (which is a considerable amount). The successor warhead, the MR41 was a boosted-fission warhead for the MSBS M1 and M2 SLBMs and had a yield of 500 kilotons and weighed 700kg.
To what yield are India's fission and/or boosted-fission designs scalable ?
Do the large payloads of the Agni series lead to the inexorable conclusion that large fission or boosted-fission weapons are the ones deployed ?
Without an analysis of this question, everybody who is attempting to tell the world they know what India's deterrent consists of is merely whistling in the wind - adding nothing but noise to a debate that has seen Dr. Santhanam being described as a nuclear scientist (when he is not) and Dr. Kalam being told to shut up because he is not a nuclear scientist and which has seen the POK-1 1974 test team turn on the 1998 team without remembering that the yield of their test in 1974 was also hotly disputed.
There are no heroes in this drama. What India needs to do is ignore the rhetoric and analyse whether its fission and boosted-fission capability can reliably deliver warheads in the 50-100 kiloton class to the armed forces with confidence.