Figures Claimed By Both India and Pakistan Are Disputed
Pakistan Nuclear Weapons
A Brief History of Pakistan's Nuclear Program
Pakistan's nuclear weapons program was established in 1972 by Zulfiqar Ali Bhutto, who founded the program while he was Minister for Fuel, Power and Natural Resources, and later became President and Prime Minister. Shortly after the loss of East Pakistan in the 1971 war with India, Bhutto initiated the program with a meeting of physicists and engineers at Multan in January 1972.
India's 1974 testing of a nuclear "device" gave Pakistan's nuclear program new momentum. Through the late 1970s, Pakistan's program acquired sensitive uranium enrichment technology and expertise. The 1975 arrival of Dr. Abdul Qadeer Khan considerably advanced these efforts. Dr. Khan is a German-trained metallurgist who brought with him knowledge of gas centrifuge technologies that he had acquired through his position at the classified URENCO uranium enrichment plant in the Netherlands. Dr. Khan also reportedly brought with him stolen uranium enrichment technologies from Europe. He was put in charge of building, equipping and operating Pakistan's Kahuta facility, which was established in 1976. Under Khan's direction, Pakistan employed an extensive clandestine network in order to obtain the necessary materials and technology for its developing uranium enrichment capabilities.
In 1985, Pakistan crossed the threshold of weapons-grade uranium production, and by 1986 it is thought to have produced enough fissile material for a nuclear weapon. Pakistan continued advancing its uranium enrichment program, and according to Pakistani sources, the nation acquired the ability to carry out a nuclear explosion in 1987.
Nuclear Tests
On May 28, 1998 Pakistan announced that it had successfully conducted five nuclear tests. The Pakistani Atomic Energy Commission reported that the five nuclear tests conducted on May 28 generated a seismic signal of 5.0 on the Richter scale, with a total yield of up to 40 KT (equivalent TNT). Dr. A.Q. Khan claimed that one device was a boosted fission device and that the other four were sub-kiloton nuclear devices.
On May 30, 1998 Pakistan tested one more nuclear warhead with a reported yield of 12 kilotons. The tests were conducted at Balochistan, bringing the total number of claimed tests to six. It has also been claimed by Pakistani sources that at least one additional device, initially planned for detonation on 30 May 1998, remained emplaced underground ready for detonation.
Pakistani claims concerning the number and yields of their underground tests cannot be independently confirmed by seismic means, and several sources, such as the Southern Arizona Seismic Observatoryhave reported lower yields than those claimed by Pakistan. Indian sources have also suggested that as few as two weapons were actually detonated, each with yields considerably lower than claimed by Pakistan. However, seismic data showed at least two and possibly a third, much smaller, test in the initial round of tests at the Ras Koh range. The single test on 30 May provided a clear seismic signal.
According to a preliminary analysis conducted at Los Alamos National Laboratory, material released into the atmosphere during an underground nuclear test by Pakistan in May 1998 contained low levels of weapons-grade plutonium. The significance of the Los Alamos finding was that Pakistan had either imported or produced plutonium undetected by the US intelligence community. But Lawrence Livermore National Laboratory and other agencies later contested the accuracy of this finding.
These tests came slightly more than two weeks after India carried out five nuclear tests of its own on May 11 and 13 and after many warnings by Pakistani officials that they would respond to India.
Pakistan's nuclear tests were followed by the February 1999 Lahore Agreements between Prime Ministers Vajpayee and Sharif. The agreements included confidence building measures such as advance notice of ballistic missile testing and a continuation of their unilateral moratoria on nuclear testing. But diplomatic advances made that year were undermined by Pakistan's incursion into Kargil. Under US diplomatic pressure, Prime Minister Sharif withdrew his troops, but lost power in October 1999 due to a military coup in which Gen. Pervez Musharraf took over.
- Satellite Imagery of Pakistan's May 28 and May 30 nuclear testing sites
Nuclear Infrastructure
Pakistan's nuclear program is based primarily on highly enriched uranium (HEU), which is produced at the A. Q. Khan research laboratory at Kahuta, a gas centrifuge uranium enrichment facility. The Kahuta facility has been in operation since the early 1980s. By the early 1990s, Kahuta had an estimated 3,000 centrifuges in operation, and Pakistan continued its pursuit of expanded uranium enrichment capabilities.
In the 1990s Pakistan began to pursue plutonium production capabilities. With Chinese assistance, Pakistan built the 40 MWt (megawatt thermal) Khusab research reactor at Joharabad, and in April 1998, Pakistan announced that the reactor was operational. According to public statements made by US officials, this unsafeguarded heavy water reactor generates an estimated 8-10 kilotons of weapons grade plutonium per year, which is enough for one to two nuclear weapons. The reactor could also produce tritium if it were loaded with lithium-6. According to J. Cirincione of Carnegie, Khusab's plutonium production capacity could allow Pakistan to develop lighter nuclear warheads that would be easier to deliver with a ballistic missile.
Plutonium separation reportedly takes place at the New Labs reprocessing plant next to Pakistan's Institute of Nuclear Science and Technology (Pinstech) in Rawalpindi and at the larger Chasma nuclear power plant, neither of which are subject to IAEA inspection.
Nuclear Arsenal
The Natural Resources Defense Council (NRDC) estimates that Pakistan has built 24-48 HEU-based nuclear warheads, and Carnegie reports that they have produced 585-800 kg of HEU, enough for 30-55 weapons. Pakistan's nuclear warheads are based on an implosion design that uses a solid core of highly enriched uranium and requires an estimated 15-20 kg of material per warhead. According to Carnegie, Pakistan has also produced a small but unknown quantity of weapons grade plutonium, which is sufficient for an estimated 3-5 nuclear weapons.
Pakistani authorities claim that their nuclear weapons are not assembled. They maintain that the fissile cores are stored separately from the non-nuclear explosives packages, and that the warheads are stored separately from the delivery systems. In a 2001 report, the Defense Department contends that "Islamabad's nuclear weapons are probably stored in component form" and that "Pakistan probably could assemble the weapons fairly quickly." However, no one has been able to ascertain the validity of Pakistan's assurances about their nuclear weapons security.
Pakistan's reliance primarily on HEU makes its fissile materials particularly vulnerable to diversion. HEU can be used in a relatively simple gun-barrel-type design, which could be within the means of non-state actors that intend to assemble a crude nuclear weapon.
The terrorist attacks on September 11th raised concerns about the security of Pakistan's nuclear arsenal. According to press reports, within two days of the attacks, Pakistan's military began relocating nuclear weapons components to six new secret locations. Shortly thereafter, Gen. Pervez Musharraf fired his intelligence chief and other officers and detained several suspected retired nuclear weapons scientists, in an attempt to root out extremist elements that posed a potential threat to Pakistan's nuclear arsenal.
Concerns have also been raised about Pakistan as a proliferant of nuclear materials and expertise. In November, 2002, shortly after North Korea admitted to pursuing a nuclear weapons program, the press reported allegations that Pakistan had provided assistance in the development of its uranium enrichment program in exchange for North Korean missile technologies.
Foreign Assistance
In the past, China played a major role in the development of Pakistan's nuclear infrastructure, especially when increasingly stringent export controls in western countries made it difficult for Pakistan to acquire materials and technology elsewhere. According to a 2001 Department of Defense report, China has supplied Pakistan with nuclear materials and expertise and has provided critical assistance in the construction of Pakistan's nuclear facilities.
In the 1990s, China designed and supplied the heavy water Khusab reactor, which plays a key role in Pakistan's production of plutonium. A subsidiary of the China National Nuclear Corporation also contributed to Pakistan's efforts to expand its uranium enrichment capabilities by providing 5,000 custom made ring magnets, which are a key component of the bearings that facilitate the high-speed rotation of centrifuges.
According to Anthony Cordesman of CSIS, China is also reported to have provided Pakistan with the design of one of its warheads, which is relatively sophisticated in design and lighter than U.S. and Soviet designed first generation warheads.
China also provided technical and material support in the completion of the Chasma nuclear power reactor and plutonium reprocessing facility, which was built in the mid 1990s. The project had been initiated as a cooperative program with France, but Pakistan's failure to sign the NPT and unwillingness to accept IAEA safeguards on its entire nuclear program caused France to terminate assistance.
According to the Defense Department report cited above, Pakistan has also acquired nuclear related and dual-use and equipment and materials from the Former Soviet Union and Western Europe.
Intermittent US Sanctions
On several occasions, under the authority of amendments to the Foreign Assistance Act, the U.S. has imposed sanctions on Pakistan, cutting off economic and military aid as a result of its pursuit of nuclear weapons. However, the U.S. suspended sanctions each time developments in Afghanistan made Pakistan a strategically important "frontline state," such as the 1981 Soviet occupation and in the war on terrorism.
Pakistan's Nuclear Doctrine
Several sources, such as Jane's Intelligence Review and Defense Department reports maintain that Pakistan's motive for pursuing a nuclear weapons program is to counter the threat posed by its principal rival, India, which has superior conventional forces and nuclear weapons.
Pakistan has not signed the Non-Proliferation Treaty (NPT) or the Comprehensive Test Ban Treaty (CTBT). According to the Defense Department report cited above, "Pakistan remains steadfast in its refusal to sign the NPT, stating that it would do so only after India joined the Treaty. Consequently, not all of Pakistan's nuclear facilities are under IAEA safeguards. Pakistani officials have stated that signature of the CTBT is in Pakistan's best interest, but that Pakistan will do so only after developing a domestic consensus on the issue, and have disavowed any connection with India's decision."
Pakistan does not abide by a no-first-use doctrine, as evidenced by President Pervez Musharraf's statements in May, 2002. Musharraf said that Pakistan did not want a conflict with India but that if it came to war between the nuclear-armed rivals, he would "respond with full might." These statements were interpreted to mean that if pressed by an overwhelming conventional attack from India, which has superior conventional forces, Pakistan might use its nuclear weapons.
Sources and Resources
- UN Nuclear Chief Warns of Global Black Market Mohammed ElBaradei commenting on questions raised by the Khan confession, February 6, 2004.
- Abdul Qadeer Khan "Apologizes" for Transferring Nuclear Secrets Abroad, broadcast on Pakistani television, February 4, 2004.
- Documents Indicate A.Q. Khan Offered Nuclear Weapon Designs to Iraq in 1990: Did He Approach Other Countries? By David Albright and Corey Hinderstein, February 4, 2004
Deadly Arsenals, chapter on Paksitan - by Joseph Cirincione, John B.Wolfsthal and Miriam Rajkumar (Carnegie, June 2002). The chapter discusses Pakistan's WMD, missile and aircraft capabilities. It also presents the strategic context of the nuclear arms race between India and Pakistan and the history of Pakistan's nuclear weapons program, touching on foreign assistance from China and on-and-off US economic assistance.
- Proliferation: Threat and Response, Jan. 2001 - A Defense Department report on the status of nuclear proliferation in South Asia. It includes a brief historical background on the conflict between India and Pakistan as well as an assessment of their nuclear capabilities, chem/bio programs, ballistic missile programs and other means of delivery.
- ENHANCING NUCLEAR SECURITY IN THE COUNTER-TERRORISM STRUGGLE: India and Pakistan as a New Region for Cooperation - by Rose Gottemoeller, Carnegie Endowment for International Peace, August 2002. This working paper explores possible cooperative programs that could enhance the security of Pakistan and India's nuclear arsenals, in order to prevent the diversion of dangerous materials into the hands of terrorists or rogue state leaders.
- "Pakistan's Nuclear Forces, 2001" from NRDC Nuclear Notebook, Bulletin of Atomic Scientists Jan/Feb 2002. A Two-page update on the state of Pakistan's nuclear arsenal. It makes rough estimates of the number of nuclear weapons and the amount of fissile material in Pakistan's possession and touches on fissile material production capabilities. Also included is a brief discussion of delivery mechanisms such as aircraft and missiles.
- Monterey Institute Resource Page on India and Pakistan - last updated July 7, 2000. This page has many useful links to relevant maps, news articles and analytical pieces on India and Pakistan's nuclear programs.
- Carnegie Endowment for International Peace - Pakistan resources
- Pakistan Nuclear Weapons - A Chronology - a timeline of the Pakistan's Nuclear Development program since 1965.
- "The Threat of Pakistani Nuclear Weapons" - a CSIS report by Anthony H. Cordesman (Last updated Nov. 2001). - This report tells the history of Pakistan's nuclear weapons program and discusses China role in its development. It also lists recent US intelligence reports on Pakistan's activities.
- From Testing to Deploying Nuclear Forces: The Hard Choices Facing India and Pakistan - Gregory S. Jones. (Rand, 2000). "This issue paper describes the requirements for a nuclear deterrent force in general terms, discusses how the Indian-Pakistani nuclear relationship is affected by China, and then considers the specific decisions that still must be made in India and Pakistan."
- Pakistan Nuclear Update, 2001 - Wisconsin Project. This three-page document provides a brief summary of Pakistan's main nuclear sites and an update on developments in Pakistan's nuclear program.
- Securing Pakistan's Nuclear Arsenal: Principles for Assistance - by David Albright, Kevin O'Neill and Corey Hinderstein, Oct. 4, 2001. An ISIS issue brief on the potential threats to the security of Pakistan's nuclear arsenal.
- The May 1998 India and Pakistan Nuclear Tests - by Terry C. Wallace, Southern Arizona Seismic Observatory (SASO), 1998. This technical paper provides a seismic analysis of India and Pakistan's 1998 nuclear tests. It concludes that Pakistan's May 28 tests had a seismic yield of 9-12 kt, and the May 30 test had a yield of 4-6 kt. An updated web page on this report can be found here
- Satellite Imagery of Pakistan's May 28 and May 30 nuclear testing sites, hosted on the Center for Monitoring Research Commercial Satellite Imagery Page
- "Pakistan's Nuclear Dilemma" - September 23 2001, Carnegie Endowment for International Peace. Transcripts from a Carnegie panel on developments in Pakistan in the aftermath of the Septempber 11th attacks. The panel included three speakers -- Shirin Tahir-Kheli, George Perkovich and Rose Gottemoeller-- and was moderated by Joseph Cirincione.
- Chapter on Pakistan, from Tracking Nuclear Proliferation: A Guide in Maps and Charts, 1998 by Rodney W. Jones, Mark G. McDonough, with Toby F. Dalton and Gregory D. Koblentz (Washington, DC: Carnegie Endowment, July 1998). This chapter documents the history of Pakistan's nuclear program and tracks the development of its nuclear infrastructure. It also covers in detail the sanctions the US imposed on Pakistan in light of these developments, as well Pakistan's missile program.
- "U.S. Appears to be Losing Track of Pakistan's Nuclear Program" and "U.S. Now Believes Pakistan to use Khushab Plutonium in Bomb Program" By Mark Hibbs July, 1998. Two brief articles written in the aftermath of Paksistan's 1998 nuclear tests -- they discuss Pakistan's weapons grade uranium and plutonium production capacities and the implications for its nuclear arsenal.
- "U.S. Labs at Odds on Whether Pakistani Blast Used Plutonium," by Dana Priest Washington PostSunday, January 17, 1999; Page A02. This article discusses the controversy over the preliminary analysis carried out by Los Alamos National Laboratory, which found that plutonium traces had been released into the atomosphere during Pakistan's May 30th underground nuclear test. Scientists at Lawrence Livermore National Labs contested the accuracy of this finding and alleged that Los Alamos had contaminated and then lost the air sample. At the time, Los Alamos' findings were highly controversial because they implied that Pakistan had obtained plutonium either though imports or indigenous production, and there was uncertainty about Pakistan's plutonium production capabilities. It is now public knowledge that Pakistan can produce and isolate plutonium at its Khusbab reactor and at the New Labs and Chasma separation facilities.
- NUCLEARISATION OF SOUTH ASIA AND ITS REGIONAL AND GLOBAL IMPLICATIONS Munir Ahmed Khan REGIONAL STUDIES Autumn 1998
So the Clear Estimation of Pakistan Nukes is 140 x12KT = 1.7 Megatons Roughly
Now India
The nuclear devices were moved from their vaults at the BARC complex in Mumbai in the early morning hours of 1 May, around 3 a.m., by four Army trucks under the command of Col. Umang Kapur of the DRDO (Defence Research and Development Organization). They were transported to Mumbai airport and flown at dawn in AN-32 transports to Jaisalmer airport, two hours away. An Army convoy of four trucks took the explosive devices to Pokhran, about an hours trip from the airport. Three trips were required to complete the delivery of the devices and associated equipment. The devices were delivered directly to the device preparation building which was designated Prayer Hall.
according to Chengappa the plutonium for the devices weighed 3 to 8 kg, depending of the device, and were colored gray due to the coating applied to contain the radioactivity (and no doubt to prevent oxidation of the plutonium). The explosives surrounding the cores was colored a dull orange.
Three laboratories of the DRDO were involved in designing, testing and producing components like advanced detonators, the implosion systems, high-voltage trigger systems. They were also responsible for weaponization -- systems engineering, aerodynamics, safety interlocks and flight trials.
The tests were organized into two groups that were fired separately, with all of the devices in a group fired at the same time. The first group consisted of the thermonuclear device, the fission bomb, and a sub-kiloton device, and two more sub-kiloton devices made up the second group.
The First Tests Are Fired
The thermonuclear device was emplaced in the shaft code named White House (over 200 m deep), while the Taj Mahal shaft (over 150 m deep) was assigned to the fission bomb, and Kumbhkaran to the first sub-kiloton shot. The other three shafts for the second test series were designated NT 1,2, and 3.
The Regiment 58 Engineers had learned a lot since 1995 about how to avoid detection by U.S. spy satellites. A lot of work was done at night, and heavy equipment was always returned to the same parking spot at dawn so that image analysts would conclude that they had never moved. Piles of sand were shaped to mimic the wind-aligned and shaped dune forms in the area. When cables were laid they were carefully covered and native vegetation replaced to conceal the digging.
The first three devices were emplaced on 10 May, the day before the tests. The shafts were L-shaped, with a horizontal chamber for the test device. The first device to be placed was the sub-kiloton device in the Kumbhkaran shaft. The Army engineers sealed the shaft at 8:30 p.m. Then the thermonuclear device was lowered in the White House shaft, sealing this shaft took until 4 a.m. the next morning. By then the atomic bomb was being emplaced in the Taj Mahal shaft. It was sealed at 7:30 a.m., just 90 minutes from the planned test time.
Seismic data collected by stations outside of India have placed the total magnitude of the first event at 5.0 (+/- 0.4), making it one of the largest seismic events in the world during the 24 hr period in which it occurred. The measured seismic center of the triple event was located at 27.0716 deg N latitude, and 71.7612 deg E longitude, which places it only 2.8 km from the 1974 test site (which was at 27.095 deg N, 71.752 deg E). The general area of these tests is usually given as Pokharan (or Pokhran), a town about 25 km away. This is area is a military test range with four areas (A through D). The test sites are just outside the abandoned village of Malka, are 6 km to the northeast of the nearest inhabited village of Khetolai (population 1200), and 10 km south of Loharki, and are about 100 km from the Indian border with Pakistan.
The first group of three tests (Shakti I, II, and III) were reported to have a combined yield of about 55 (or 58) kilotons and consisted of a two stage thermonuclear weapon design (Shakti I) with a yield of 43 kt, +/- 3 kt, (also stated to be 43-45 kt), a 12 kt test of a light compact weaponized tactical fission bomb, and a 0.2 kt tactical fission weapon. There were three shafts located about 1 km from each other and 3.5 km from the control room. The Shakti I shaft was designated "White House" (also called "Whisky"), the Shakti II shaft was known as "Taj Mahal" (also called "Tango"), and the Shakti III shaft was called "Kumbhkaran". The shots were fired simultaneously. The second phase of two tests (Shakti IV and V) had yields of 0.5 and 0.3 kilotons, and were fired in shafts designated NT 1 and 2 (for Navtala, the area where they were dug). A third device and shaft (NT 3) was prepared but was not fired. The second group of shots was conducted to generate additional data for improved computer simulation of designs.
Though The claimed yields of these devices is not well supported by available evidence. Assigning yields to the different devices from direct outside measurement is impossible since only the total yield of all three can be measured. For detailed discussion of this see
Mouth of a test shaft after the 11 May 1998 detonation. Either the White House or Kumbhkaran shaft.
This was a test of reduced yield two-stage thermonuclear bomb using a fusion boosted fission primary, apparently a 43-45 kt design test yield for a ~300 kt weapon. The available evidence indicates that the boosted primary performed correctly, but that the secondary stage failed partially.
The Yield of Pokhran I (Smiling Buddha)
The first Indian test - Pokhran I or "Smiling Buddha" - was originally reported by the Indian AEC (Atomic Energy Commission) Chairman Homi Sethna on the day of the test to have had a yield of between 10 and 15 kilotons. Subsequently nearly all reports described the yield as 12 kilotons, or 12 to 15 kilotons [Perkovich 1999, p. 181] (and occasionally as high as 15 to 20 kilotons, [Perkovich 1999, p. 522]). In a paper presented to the IAEA in January 1975 Ramanna and Chidambaram placed the yield at 12 kilotons. Official reports following the 1998 Shakti test series have repeated this figure, or nudged it up to 13 kilotons.
On the other hand, other reports over the years have placed the yield much lower. U.S. analysts have estimated the yield as 4 to 6 kilotons [Wallace 1998, p. 3] (or go to his on-line reprint), and Indian journalists have published reports of yields as low as 2 kilotons.
Two former chairmen of the AEC have conceded in interviews that the test yield was lower than the official 12 kt figure[Perkovich 1999, p. 182]. Sethna stated in 1996 that "the yield was much lower than had been stated". P.K. Iyengar has repeatedly cited a yield range of 8-10 kt, though seeming to favor yields ranging from 8 to approaching 10 (but never as high as 10) at different times. In [Perkovich 1999] he is cited as offering a figure of 8-10 kt (further elaborating that the design yield was 10 kt). In [Albright 1998a] Iyengar says that based on a radiochemical analysis of samples of bomb debris taken from the shaft, the yield of the 1974 shot was closer to 10 than eight kilotons. In [Douglas et al 2001; p. ] (quoting from Gupta, V. and Pabian, F., Sci. Global Security, 1996, 6, 101-189) he is cited as saying that the yield was 8 kt ‘exactly as predicted’. Since Iyengar was second-in-command of the development and test program for Pokhran-I, as well as AEC Chairman later, and this statement contradicts official figures, his opinion on this must be accorded significant weight. The Indian government has never released the results of radiochemical tests that would give unambiguous evidence of yield.
Estimated claim of pokhran -1(1974) Test Was 8-10 KT By All experts
The Yields of Pokhran II (Operation Shakti)
The yields claimed for the initial simultaneous Shakti I-III three shot test on 11 May were 43 kt, +/- 3 kt (for a thermonuclear device test, also stated to be 43-45 kt), 12 kt (an improved fission bomb design), and 0.2 kt. As with Pokhran-I, these yield claims have been controversial from the start.
Three approaches exist for estimating yield from the seismic data:
- Direct seismic yield estimation - calculating the yield directly from the Pokhran-II seismic signal strength;
- Comparative seismic yield estimation - comparing the seismic magnitude estimates for Pokhran-II to similar estimates for Pokhran-I, and using independent yield data for P-I to calculate P-II; and
- Comparative signal estimation - directly comparing the signal strength for Pokhran-I and II, without attempting intervening magnitude or yield estimation, and using independent yield data for P-I to calculate P-II.
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Problems specific to the first approach is accounting for all the variables that influence the apparent signal produced by a given yield. These include coupling of the explosion to the medium surrounding it, local signal propagation in the test area, and long distance signal propagation to the measuring site. As noted above the relationship between a measured signal and the actual yield can vary over a factor of at least 6, even if no unusual coupling factors are involved.
Both the second and third approaches are plagued by uncertainties regarding the yield of P-I which make it problematic as a basis of estimating P-II. In addition the second method shares some of the problems of the first with accounting for variables that affect apparent yield, and also must deal with additional sources of error from computing seismic yields for both P-I and P-II separately. The third method has fewer uncertainties to deal with, but is limited by the small number of seismic stations that recorded both tests. Only data from measuring stations that directly measured both tests can be used.
A graph derived from close in acceleration measurements around the P-II test site is presented in [Sikka et al 2000; pg. 1365]that shows close similarity between the measured values at P-II and two Plowshare shots (Rulison and Rio-Blanco), when scaled to 58 kt. Unfortunately the measurement data itself has not been released for independent analysis, and the graph presented has no scale values for the acceleration axis. Without actual data this claim cannot be evaluated, much less confirmed.
An interesting comment by Chengappa may shed some significant light on whether the Shakti-I device truly performed as expected:
Some of the scientists looked worried. There was concern over whether the secondary fusion stage had properly detonated... Even Indian scientists like Iyengar, the former AEC chairman, doubted whether the test was fully successful.
[Chengappa 2000; p. 431]. In April 2000 P.K. Iyengar went on record with the
Times of India as stating that the secondary stage of this device was only partially successful, a claim subsequently denied by BARC.
Yield estimation by analysis of cratering morphology is complicated in the case of the Shakti tests since the precise burial depth is not known as of this writing. Chengappa gives a depth of the 'White House' shaft for the Shakti I thermonuclear device as "over 200 meters"
[Chengappa 2000; p. 427]. A notable feature of this shot is the lack of significant surface disturbance, unlike the fission shot in the 'Taj Mahal' shaft and Smiling Buddha. Chengappa describes the effect seen by observers on the scene:
"The Taj Mahal site had a giant newly formed crater. But the hydrogen bomb site wasn't as impressive. A mound of several of several meters had risen and sheds all round it had collapsed in a crazy heap."
[Chengappa 2000; p. 431]
The fact that the Shakti I shot was completely contained, and produced no subsidence crater allows some consistency checking, but without placing significant constraints on yield. The reported mound (not visible in available photographs) is not a retarc, such low relief structures are not infrequently produced by deep shots (see
Fig. 6-f).
Chengappa reports that the Shakti I shot was fired in granite stratum at a depth of "over 200 meters". Since the shaft is only 1000 meters from the Shakti II shot (with a burial depth of "over 150 m" deep
[Chengappa 2000; p. 422]) that was evidently not fired in granite the obvious interpretation is that somewhere below 150 m the porous rock used in Pokhran-I and Shakti-II is underlaid by granite stratum.
Using the scaling law and constants for granite found
here it can be determined that a 43 kt explosion at a depth of 200 m (the limiting case) in granite would produce a cavity with a radius of 42 - 44 m, and a chimney rising 176 - 300 m (i.e. reaching the surface) given that the chimney formation would be through porous non-granitic rock. Since the near surface of the Pokhran site is composed of loose material (sand and perhaps alluvium) that cannot cap chimney formation it seems unlikely that a 43 kt shot at 200 m could have avoided producing a subsidence crater. If the depth was 250 m the cavity would have been modestly smaller 40 - 42 m, and the chimney height similarly reduced. This makes capping of the subsidence chimney plausible, though a crater could still have occurred under favorable circumstances. The combination of geological factors, depth and yield reported from Indian sources thus is consistent with the observed effects. The observed effects are also consistent with lower yields of course. The absence of a subsidence crater however effectively rules out a burial depth of only 200 m however with the reported yield.
By comparison the Shakti II fission shot, at 12 kt, produced a large subsidence crater in a shaft "over 150 m" deep
[Chengappa 2000; p. 422]. If the depth were exactly 150 m the scaled depth would be 215 feet, consistent with the crater formation, though it could easily be deeper and produce the observed effects. The expected cavity radius would also be about 42 m, due to the shallower burial depth and softer rock, and the chimney would be certain to reach the surface. This is also consistent with the roughly 80 m crater shown
here, since the radius of the chimney and subsidence crater is usually about the same as the original cavity (cf. Smiling Buddha above).
One radiochemical analysis of the thermonuclear device test has been published in the BARC newsletter,
[Manohar et al 1999]. This analysis attempts to calculate the total quantity of fissions that occurred and thus the total yield of the device (a fission-fusion-fission system in which fission would dominate the total yield). The method chosen was to measure the vertical distribution of fission products and fusion neutron activated isotopes in two bore holes (one at the center, and one offset by 32 m). Then by assuming a uniform distribution out to an estimated radius of the final cavity (claimed to be 40 m +/- 4m) the total quantity of isotopes was estimated. The yield estimate obtained was 50 kt with a claimed uncertainty of +/- 10 kt.
Radiochemical analysis is commonly said to be the most accurate means of yield determination. But this statement refers to an entirely different type of radiochemical analysis from what BARC performed in this study. The most accurate method is to determine the percentage of material fissioned by comparing the ratio of fission products to fissile material in a sample, thus giving the efficiency directly and with knowledge of the weapon design (how much fissile material is present) the yield can be easily calculated. Unfortunately publishing such data also discloses weapon design information normally kept secret. Attempting to directly calculate the total amount of fission is fraught with problems in accurately determining the three dimensional distribution of the material throughout the collapsed blast cavity.
The data presented by India do not justify the claim of a 40 m radius uniform distribution for computing total activity. The two borings described only set a lower limit of 32 m, the claim for 40 m is based on an inference from the crush zone radius which was estimated to be 60 m (with unspecified precision). This does not provide a convincing basis for distinguishing between a 40 m cavity and one that is slightly more than 32 m. The 40 m radius does match the Indian a priori yield claim of 43 kt, raising the question of whether assumptions are being matched to desired conclusions. Replacing BARC's 40 m radius with 32 m in their computation would demote the yield estimate to 32 +/- 3 kt (using their specified 8% radioactivity measurement error) and bringing the lower yield limit down to 29 kt or so.
The Indians also reported having performed another type of yield determination test - CORRTEX, which is a sophisticated hydrodynamic measurement technique. The results of this test are not available.
Taking all these factors together, it appears that Shakti II is indeed about 12 kt as claimed. But Shakti I seems limited to about 31 kt, plus some margin of uncertainty that may bound it in the mid-30s. The various other data marshaled by BARC do not prove a yield larger than 29 kt, which closely matches the seismic upper limit of circa 35 kt as perhaps the most plausible yieldfor Shakti I. This would be consistent with a partially successful thermonuclear test with a roughly 15 kt primary stage and a 15 kt secondary yield.
The consensus among outside seismic experts is that the yields of most Indian tests are overstated (particularly Pokhran-I or "Smiling Buddha" and Shakti-I), and that the very existence of Shakti IV-V is in question. Interestingly, the case with the Pakistani tests (conducted in a far different geological environment) is similar - claimed yields do not match the seismic evidence. No well-founded explanation is available for such a consistent pattern of deception by both India and Pakistan .
So That Maximum Plausible Yield Of India 2 stage Controlled Thermonuclear Nuclear Test Was 31-35 KT By all Estimates
So,Finally The Clear Estimate of Indian Nukes are 120x 35KT(Highest Estimate) =4.2 Megatons Precisely
rest keep barking to hide the shameful performance of your military.
