NoKo/Pak H-bomb test superior to Indian S-1

Several conclusions in my previous blog (“Rogue Triad and H-Bomb Tests”) have been borne out. According to a source, it is confirmed that what was exploded was a fusion-boosted fission device of Pakistani design that was vetted/refined by Chinese weapons scientists. Officially, South Korean siesmic sensors read 4.7+ on the Richter scale, the US 4.9+, Japanese 5.2+, but the most reliable read is from the Russian station at Petropovlovsk on the Kamchatka Peninsula nearest to the test site with 5.3-5.5+ Richter. Petropovlovsk also has, according to this source, a radionuclide detection facility. While the Granite stratum of the Hamygeong test site dampened/suppressed the shock waves, the 5.5 on Richter translates into a certifiably estimated 20-30 Kiloton explosion. This, on the face of it, is a better performing design than the S-1 device tested in Pokhran on May 11, 1998. This should worry GOI enough for it to order resumption of N-testing, because now there’s no doubt whatsoever about Pakistan obtaining, centrally with Chinese help and assistance, thermonuclear armaments.

About Bharat Karnad

Senior Fellow in National Security Studies at the Centre for Policy Research, New Delhi, he was Member of the (1st) National Security Advisory Board and the Nuclear Doctrine-drafting Group, and author, among other books of, 'Nuclear Weapons and Indian Security: The Realist Foundations of Strategy', 'India's Nuclear Policy' and most recently, 'Why India is Not a Great Power (Yet)'. Educated at the University of California (undergrad and grad), he was Visiting Scholar at Princeton University, University of Pennsylvania, the Shanghai Institutes of International Studies, and Henry L. Stimson Center, Washington, DC.
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27 Responses to NoKo/Pak H-bomb test superior to Indian S-1

  1. satyaki says:

    Bharat Sir,

    What was S-1’s yield ? About 25 kt ?

    • Juuso says:

      Indian government claim: 45-65kt
      Western experts: 20-30kt.

      Pakistan claimed back in 1998 that they detonated at least one weapon with 40kt yield, but western experts put all their test yields below 20kt. When it comes to weapon yields, India and Pakistan seem to be sitting in a same line.

  2. satyaki says:

    Indeed the NoKo/Pak test aooears to be that of a primary for a thermonuclear weapon. Similar to the S-1 parry, possibly.

  3. satyaki says:

    Bharat Sir,

    I just read one of K Santhanam’s interviews. He says S-1 was 20-25 kt. Since the secondary of S-1 had essentially zero yield, the primary was 20-25 kt (more or less like the current NoKo test).

  4. Yusuf says:


    The South Koreans have put a yield of 6kt. This test was certainly not a thermonuclear test. Yes it does represent an improvement for NoKo as its first two tests were duds.

    As far as Pak is concerned, you have never spoken about how Pak moved from Uranium to Pu based weapons in the last 10 years. They have not even tested a Pu bomb. It can only be possible if there was more proliferation from China with Pu designs.

    As far as my opinion goes, there is a major reliability issue with Pak nukes with no good test data. The west regards its tests as duds.

    Pak is building bombs like crazy coz it knows they are not reliable and hopes that one of them explodes if it ever uses them. Their missiles reliability or the lack of it has been completely exposed. They kept claiming success while their missiles kept failing test after test.

    Sent from my iPhone

    • That’s an interesting point you make about making as many bombs as possible just so some of them explode. Then again, the Khushab Pu dedicated reactors I & II have been operating — esp Khushab-I for some time, and China has been a constant companion, helping with ‘technical advice’ and both Pakistan and China have a close relationship with NoKo (with NoKo’s Nodong missile tech transfer to Pakistan).

      • Vihan says:

        There is also some sporadic information which I am inclined to believe that Pakistani scientists, engineers, technicians and military men have been present during some of China’s nuclear testing during the 1980’s. There is also some more information which I am also inclined to believe that the Chinese have tested at lease one device for the Pakistani’s either during the late 1980’s or 1990’s.

        Our worst case estimate should be that Pakistan did get proven Plutonium fission bomb designs and/or ready made weapons from China, and have been pursuing the goals of Uranium bombs, as well as boosted fission, thermonuclear and tactical weapons. What we will actually do about it is of course is something I can only hope from a new government.

  5. satyaki says:

    With the next few NoKo tests, Pak will have a proven TN of around 200 kt yield (current test appears in the same league as the S-1 primary). While we have only the unproven 125-175 kt thermonuclear weapons.

    Does this give Pak nuclear superiority where they have a high probability of decisively winning a nuclear conflict ? Or does our deterrent stay where it is: credible vis a vis Pak for geographic reasons while not yet so against PRC (unless we test to confirm our TN) ?

  6. Pingback: India sees Pakistani hand in North Korear's nuclear test

  7. sbm says:

    Sir, I would suggest that India needs to resume thermonuclear testing (with due regard for consequences of course) regardless of the DPRK/Pak test. Looking at the yield estimates of both the Pak and DPRK tests (seismic etc.) I am inclined to believe the lower estimates. However, that does not invalidate your point – India needs reliable Thermonuclear weapons.

    As you indicated in your book India’s nuclear policy, the thermonuclear arsenal is not reliable and building a deterrent around fission and boosted-fission weapons is expensive in plutonium terms and is far from satisfactory.

    I would ask you this – it is now 2013 – what is your estimate of India’s nuclear arsenal and Agni missile stocks ?


  8. aamatya says:

    Sitting on past glories is just not enough because the enemy capabilities, by all means-beg,borrow or steal, are improving. India must look for new sites to conduct new tests. They could be under oceans where seismic activity is high or just with any other credible cover-up.
    But all this talk is in vain unless we show some spine and resolve in the government.

  9. Shiv says:

    Let’s not hype up things with fantasy. The Indian H-bomb had a ~20 KT yield boosted fission primary (5 KT device boosted by a factor of four). The secondary was a cylindrical design that was “de-fueled” to explode at a reduced yield of 25 KT.

    The actual test yield may have been less…but within 10-15% of the design calculation, as is alleged by R Chidambram [whom I hate with a passion – and consider the arch type of a dumb, underperforming genius who let India down]. I still expect around 40 KT of energy from the hydrogen bomb.

    The mb [body wave magnitude] value on the Richter scale from a USGS machine in Tibet was ~5.2. In hard water-saturated rock that may indicate a yield of about 15 KT but in soft, dry porous materials the yield could easily be 25 KT to 30 KT(a figure ironically supplied by the USGS in 1998 – which contradicts figures by Wallace and Los Alamos).

    As the max mb value was 5.4 (except for stray readings which went all the way to 5.8), we can easily accept a 30-60 KT rating supplied by a seismic researcher at the University of Leeds – published in a science journal in 1998.

    That said – the single test would be insufficient for a reliable weapon. You would need about 5 tests at full yield for total confidence in the physics design – this based off the writings of Ray Kidder, a former LLNL weapons engineer. With simulations you can reduce the testing to four devices.

    What this means is that India can explode a boosted fission device with a ~15-20 KT yield quite dependably, but not have any high confidence in the secondary device [hence the full hydrogen bomb] working dependably, and there would be very minimal confidence that the bomb can explode even near 200 KT.

    So thanks to the slip shod work done by the DRD and BARC, we can’t be confident much beyond 20 KT. Even so…that is just about enough for a basic deterrent.

    Pakistan tested a ~22-25 KT yield device in circa 1998, though it appears to have underperformed due to either manufacturing defects or the tritium not being replenished. That said, they have a reliable design, as attested by American nuclear scientists who simulated a stolen Pakistani design weighing about 400 pounds [which is very good, and similar to Indian technology levels].

    Overall….both India and Pakistan are at the same level. India has a 20 KT yield that can be depended on, and Pakistan has pretty much a similar device in terms of yield, also boosted fission, though made of uranium [which is better than plutonium if you wanted to perform hydrodynamic or “cold” tests as you could replace the HEU with U-238/depleted uranium….while plutonium cannot be so replaced]. All in all, I would say that the Indian design is a bit lighter and the Pakistani one is easier to maintain and cold test.

    With the 20-25 KT yield capability expect as a reliable minimum yield for the Indian H-bomb (and similar from the Pakistani boosted fission device) you can use a combination of “swarming attacks” and pinpoint precision strikes to achieve damage similar to megaton yield weapons – due to dispersed blast and fire patterns. The only disadvantage is that you need at least a hundred weapons for this feat.

    All in all – both India and Pakistan can build over a hundred weapons in time, and be able to inflict massive damage on each other’s cities. India can also handle at least 2 or 3 Chinese cities while have a few dozen weapons as back up. That would be reasonable deterrent ability, albeit not very impressive… And of course, the Chinese capability is light years ahead of ours, needless to day.

    • The shortfall on S-1 yield, according to Santhanam, director, field testing, at Pokhran was way more that 10%-15% that Chidambaram put out, as lot else, by way of misinformation. If I recall right Santy’s view (in interview in Outlook of Oct 9, 2009) was that the fusion device designed for 42 KT actually produced only half as much — the falloff being significant enough for him to recommend to GOI that more tests were needed.

      • Shiv says:

        The fusion device was designed for a 45 KT yield, and reported for a 43 KT +/- 3 KT yeild, so it was described as a 43-45 KT device. One article (an American one) came up with a 42 KT figure, with no cause for this.

        Santhanam had only one way to measure the H-bomb’s yield based off the way the DRDO set up the instruments. On the other hand, BARC used a total of six methods.

        Further, BARC had a conflict with the DRDO on their instrumentation calibration. This means that they did not agree with the way the DRDO had gauged things. That counts a lot in their favor.

        If you are familiar with nuclear testing, a lot of differences can exist from tests like the CORRTEX experiment that measures crush forces on a cable. In one American test, differences of ~20 KT for a single shot (explosion) have been noticed. Moreover, the seismology estimate was ~20 – 40 KT different from the twin CORRTEX devices used. In the end, the Americans resorted to radiochemical analysis of the shaft debris to estimate yields, and never told us which figure was accurate. They had three significantly different values, and we don’t know which is correct so far (or if all three are wrong).

        The whole point is that it matters little if the device exploded at 40 KT or 25 KT. Either way, it would be insufficient for a H-bomb test. Your reliable yield would would be based off this equation:

        primary [~20 KT, perhaps a little less if the tritium is not replenished]
        + a few kilotons of fusion from some hydrogen atoms fusing

        The fusion stage could of course explode perfectly, or it may not. Without several tests to cover for manufacturing defects and also to qualify the “physics package” thoroughly, there is little confidence in it.

        In the end, India has reliable fission device technology, and so far, it’s tested up to about 20 kilotons. We are in the same league as Pakistan in that sense, though theotetically more advanced in terms of physics. [They, on the other hand, are more “street smart”.] India’s fusion technology is not proven reliable.

        Our ability to build a deterrent rests solely on fission device technology for practical purposes, though our enemy cannot be confident that the fusion stage won’t work. Chances are, it will work at some level.

  10. With all due respect I believe that indian H bomb did succeed although may be marginally underperforming. My estimate is 38-39KT for H bomb against expected value of 43-45KT and 13-15 KT for fission bomb which is as per expected value. Basically the interference between fission and fusion tests gave the reduced body wave magnitude. If you see data in north south axis, it is clearly more than that in E-W axis. In fact santhanam’s revelation may have confirmed that. The 27KT that he claims for fission bomb of that actually 13-14KT is signal from H bomb as ground accelerometers cannot distinguish signals coming from two simultaneous tests. Add this 13-14KT to 20-25 KT from DRDO instrument measurement at H bomb site, you get 37-39 KT for H bomb with upper bound of 40 KT against BARC expectation of upper bound of 45KT . Cavity analysis confirms the H bomb yields at 37-38 KT. BARC tried to brush aside DRDO as admitting even minor underperformance (of 5KT) would have led to disclosure of design details including fission fusion breakup. The crucial question is what is the fission fusion breakup. It cannot be 15KT from fission and balance from fusion because it would make indian H bomb design well ahead of chinese and american peers.My sense is that they were actually testing a 3 phase bomb- 15KT boosted fission/fission, 15KT fusion and 15 KT tamper. Instead they got 15KT fission, 15KT fusion and maybe 8-9KT from tamper.

  11. paralysisofanalysis11 says:

    Basically I think the H bomb succeeded albeit underperforming marginally (by 5KT). BARC did not want to admit that to DRDO as it would have meant giving fission fusion breakup thereby giving the design so they gave the excuse of calibration. My estimate
    Fission bomb-13-15KT against expected yield of 13-15KT
    H bomb-35-40 KT against expected design yield of 40-45KT
    If you see the seismic data NS axis values are higher than EW axis magnitude clearly indicating interference. Basically foreign seismologists refused to admit interference as it would show that H bomb worked but was not detected by the seismic network and Indian scientists tried to calculate interference to fit the yield of 40-45KT for h bomb. Santhanam has fortunately cleared the lid from this. motion sensors installed by DRDO could not give breakup of signal coming from H bomb and fission bomb site but they could give us glimpse of total yield.
    DRDO instrument ; Fission site (27-28 Kt) of which actually only 13-15KT came from fission and rest 14KT from fusion site
    H bomb site: 23-25KT
    Add 14KT to 23-25KT and subtract it from 28KT
    you get
    H bomb: 37-39KT (against expectation of 40-45KT)
    A bomb:13-15KT (within expectation)

  12. ahmad says:

    Pakistani atomic Missile and bomb superior to india’s. Only 3 minutes. I hope you will understand.

    • hindustan says:

      Due to pak small size indian 20kt nukes are enough.for china we can target there fifty nuclear reactors and some large dams with sufficient 20kt nuking reactor is also destructive to china

    • hindustan says:

      As 20kt nukes are enough to destroy pak as its size is small.for china india can strike on chinese nuclear reactors which are more then fifty with its 20kt nukes.and some dams also.

    • Sure. But hope you also understand that Pakistan will cease to exist due to an annihilatory response, and in less time.

  13. john smith says:

    At some defence claimed that india has capacity to scale its 20kt nukes to 500kt by using boosted fission tech.and this tech is present in india from 2000-2009 it true

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