Rajagopala Chidambaram, the former director of the Bhabha Atomic Research Centre (BARC), the former chairman of the Atomic Energy Commission and the former principal scientific advisor (PSA) to the government of India, passed away in the morning of January 4, 2025.
He was 88, and had served in the above capacities during the years 1990-93, 1993-2000 and 2001-2018 respectively.
Given the key roles that he played in India’s nuclear explosion tests ‘Smiling Buddha’ on May 18, 1974 (Pokhran-I) and the ‘Shakti’ series of five explosions, which included a thermonuclear device (hydrogen bomb) test, on May 11 and 13, 1998 (Pokhran-II), he has been widely described as one of the key architects of the Indian nuclear weapons programme. No doubt, he was definitely that, but a lot more. It is probably fitting to describe him as the last of the flag bearers of the legacy and holistic vision of Homi Jehangir Bhabha, the founder of the Indian nuclear programme.
Anil Kakodkar. Photo: Public domain/Wikipedia.
Some time in 1995, this writer had gone to meet him at the Department of Atomic Energy (DAE) guest house in Kidwai Nagar, New Delhi. As Chidambaram walked into the meeting room, in tow was a certain well-built younger person. He introduced him to me as ‘Dr. Anil Kakodkar, a brilliant nuclear engineer’, and added “You will see and hear more of him in the years to come”. And that has indeed been borne out to be very true.
Brahm Prakash. Photo: IISc official website.
Clearly he had acquired the same knack from Bhabha of identifying the right people just as the latter had first picked the great metallurgist Brahm Prakash to be his right hand man and later Chidambaram, a materials scientist at the Indian Institute of Science (IISc), to work with Brahm Prakash to address the various metallurgical issues involved in the early growing phase of the country’s nuclear programme.
Indeed, Brahm Prakash’s mentorship stood Chidambaram in good stead when he was faced with the metallurgical problems for carrying out India’s first nuclear test, the Peaceful Nuclear Explosion (PNE) at Pokhran in 1974.
This acute ability of Chidambaram was also in evidence when the Tata Institute of Fundamental Research (TIFR) was faced with a quandary in the selection of a new director after Virendra Singh completed his two-term tenure as the director in 1997. Chidambaram, as the Chairman of the three-man selection committee, wanted someone who knew Bhabha, understood his way of administering the institution and had the capability to strive to keep Bhabha’s legacy alive.
But, to maintain the tradition, there was no one meeting Chidambaram’s requirements under the age of 55 who could serve as director for two terms. The senior most at the TIFR then was Sudhanshu S. Jha, a condensed matter theorist, whom Bhabha had spotted as a highly promising theorist and had sent him to Stanford University to work with Felix Bloch in 1960 when he was barely 20. But in 1997 Jha was already 57. Chidambaram, after taking the faculty, researchers and students into confidence, decided to break tradition and appoint Jha, who then served for one five-year term as the TIFR director.
The PNE of May 18, 1974, was a watershed moment in the Indian nuclear programme and Chidambaram had a very important role in its execution. Sometime around 1967, when Chidambaram was 31, his senior colleague at the BARC, Raja Ramanna, tasked him with the derivation of the ‘equation of state (EOS)’ of plutonium, a physico-metallurgical problem that is critical to the design of a nuclear explosive device. But information about EOS of weapons materials was closely guarded by the nuclear weapon states (NWSs) of the time. The EOS is a thermodynamic equation relating state variables of materials under a given set of physical conditions, such as pressure, volume, temperature, or internal energy. In a nuclear device fissile material such as plutonium is brought under very high pressure for the fissile core to attain a critical density and sustain a chain reaction releasing enormous amounts of energy.
Though in his recent biographical book India Rising: Memoir of a Scientist he says, “I was surprised when he asked me to take up this work because this was a completely different field from what I was working on”, the reasons for the choice are abundantly clear. He was already a known expert in materials science, given his outstanding work in Nuclear Magnetic Resonance for his doctoral thesis followed by work in crystallography and condensed matter physics, and with the knowledge in metallurgy gained from his association with Brahm Prakash in the nuclear establishment, he was the best person who could have a go at the problem. His success in deriving the EOS ab initio formed the basis of the design of India’s first nuclear device in 1971, the one that was finally used in the Pokhran-I PNE.
APSARA reactor and plutonium reprocessing facility at BARC as photographed by a US satellite on February 19, 1966. Photo: GODL India/Public Domain/Wikipedia.
Following the Pokhran-I nuclear test, Chidambaram got interested in the field of high-pressure physics and initiated broad ‘open research’ in the field, with its obvious strategic implications as well. A whole range of instrumentation to carry out research in the field was developed and built indigenously under his guidance. He also laid the foundation of theoretical high-pressure research for calculation of EOS and phase stability of materials from first principles and the high-pressure physics group attained international recognition as well. The paper on ‘Omega Phase in Materials’ by Chidambaram and colleagues is now regarded as textbook material in materials science.
The characteristics of the 1974 test, which used a 12-kt plutonium device emplaced in a shale medium at a depth of 107 m in a chamber at the end of a L-shaped hole, “helped understanding of the explosion phenomenology, fracturing effects in rocks, ground motion, containment of radioactivity etc.”, Chidambaram wrote. He and his colleagues had written a one-dimensional computer code for the numerical simulation of the mechanical effects of underground nuclear explosions in rock called OCENER and had developed a computer simulation model based on that.
“An important aspect of this computer simulation is to delineate the fracture system in the rock medium and to select a depth of emplacement to prevent connection of the ground surface with the cavity containing the hot radioactive gases. In the PNE test of 1974 and the five tests carried out in May 1998, such simulation calculations ensured that there is no residual radioactivity on the surface at the test sites,” Chidambaram (and Surinder Sharma) wrote later in the journal Bulletin of Materials Sciences of the Indian Academy of Sciences.
Though, technically, it had all the design features of a PNE, and indeed Chidambaram had presented implications of the 1974 nuclear test (Pokhean-I) for peaceful applications of nuclear explosions at the International Atomic Energy (IAEA) in 1975, it had been planned as a technology demonstrator and the first step in the development of a strategic nuclear weapons programme.
Given that the Nuclear Non-Proliferation Treaty (NPT) was an ‘inherently unfair treaty’, Chidambaram did not believe in keeping the nuclear option open. Criticising the arbitrary cut-off date of January 1, 1967, set in the treaty for a country to be designated as a Nuclear Weapon State (NWS), he wrote “This is equivalent to saying ‘you may have a post-graduate degree but if you got it after January 1, 1967, you will be still be presumed to be uneducated’.” Like his senior colleague Raja Ramanna, he was clear on the strategic importance of the country having a demonstrated nuclear weapons capability as long as others had it.
Chidambaram as the AEC chairman and A.P.J. Abdul Kalam as the scientific adviser to the defence minister and the head of the Defence Research and Development Organisation (DRDO) were the project coordinators for the Shakti series of tests in May 1998 (Pokhran-II). Unlike the Pokhran-I test, these were openly proclaimed as successful nuclear weapon tests and projected as part of an overt Indian nuclear weapons programme. Following Pokhran-II India declared itself to be a Nuclear Weapon State (NWS).
Chidambaram had then also stated that the data from the Pokhran-II tests were sufficient for building a stockpile of nuclear weapons and no further tests were necessary. He reiterated this in August 1999 when he said that India now had the capability to manufacture a nuclear device “of any size”. An unfortunate and immediate fall-out of his involvement in the Pokhran-II tests was that, even though he was the vice-president of the International Union of Crystallography (IUCr), Chidambaram was denied a visa to attend the executive committee meeting of the IUCr in July 1998.
Former prime minister Atal Bihari Vajpayee visiting Pokhran after the 1998 nuclear tests. Photo: File photo
Despite the good deal of scientific details that were put out following Pokhran-II tests, there were doubts being expressed about the yields of the tests, the thermonuclear test in particular, not only by Western observers but by no less a person than his predecessor AEC chairman, P. K. Iyengar. Iyengar’s remarks of 2000 and those of Western commentators were picked up as late as 2009 by others like Ashok Parthasarathi and K. Santhanam to dispute the claims made by Chidambaram and Kakodkar and said that India would need to conduct further tests for establishing a credible minimum nuclear deterrence. Perhaps due to political pressure, it was left to Chidambaram to come out defending the tests on September 24, 2009, through a public point-by-point rebuttal of the doubts being expressed.
Notwithstanding his key contributions to the strategic aspects of the Indian nuclear programme, he was more concerned about India’s energy security, especially in the wake of global warming and climate change, and the important role of nuclear power in improving India’s per capita electricity consumption and sustainable development. He criticised the IAEA at its General Conference in 2000 for its increasing proliferation misconceptions and its undue emphasis on nuclear safeguards (and the consequent increasing expenditures towards that) rather than putting its efforts in promoting nuclear power in underdeveloped and developing countries though well planned international technical collaboration and cooperation programmes.
In his address at the IAEA GC of 2000 he said:
“I would like to emphasise that the IAEA was created with the main objective of accelerating and enlarging the contribution of atomic energy to peace, health and prosperity throughout the world. This is the central pillar on which the Agency should rest while giving due consideration to safeguards measures to prevent the use of Agency assistance for military proposes, and establish safety standards for protection of health and minimisation of danger to life and property. Safety and safeguards are indeed important and necessary supporting activities to enlarging and accelerating the contribution of nuclear energy for peaceful purposes. However, they cannot become activities of the IAEA overshadowing the peaceful uses of atomic energy. Primacy must be accorded to technology. This is the only way we can faithfully interpret the time-tested Statute of the Agency…Our delegation…would like to reiterate that IAEA with its comprehensive in-house expertise, as well as its access to globally available expertise, would do well to pool all resources to facilitate the role of nuclear energy in sustainable development. This is the need of the hour…”
During his time at the helm of the Indian nuclear establishment between 1993 and 2000, the Indian nuclear power programme too achieved several milestones. In June 1994, India won its first commercial heavy water export deal, with the DAE supplying 100 MT of heavy water to South Korea. Another consignment of 100 MT was exported to South Korea later in 1998 as well. The same year, after France stopped supllying low-enriched uranium (LEU) fuel for the Tarapur plant, the DAE succeeded in negotiating an agreement with China for its supply under IAEA safeguards, the first consignment of which was received in January 1995. Later in 2000, Russia replaced China in the supply of LEU for Tarapur.
The year 1995 also saw the new Narwapahar uranium mine in Jharkhand begin its operations. In March 1996, the second reprocessing plant at Kalpakkam was cold commissioned. Later in the year, India’s first U-233 fuelled research reactor Kamini of 30 kW capacity attained criticality, thus proving DAE’s capability in handling the artificial U-233 isotope, derived by burning thorium in nuclear reactors, as a fissile material for the third stage of the Indian nuclear programme. In 1997 India refused to sign the Fissile Material Cut-off Treaty (FMCT) which, India argued, being discriminatory, hampered the growth of India’s nuclear programme.
Chidambaram’s contributions in the multifarious aspects of the Indian nuclear programme are truly noteworthy. But, at the end of it all, he was basically a scientist deeply interested in material sciences, particularly the subject of quasicrystals (crystals with ordered, but aperiodic, structure). His hallmark achievement in the field was the first ever positron annihilation studies that he carried out with colleagues in 1989 to investigate the gaps and defects in a quasicrystalline aluminum-manganese alloy. Indeed, after the period of his intense involvement in the country’s strategic programmes during the mid- to the late-1990s, he returned to doing research in the area which he continued with younger colleagues till 2004.
He was equally concerned with the Indian higher education system and the Indian research and development. A little known fact is that Chidambaram (and separately Kalam), heading different committees during the Vajpayee regime, were the earliest to moot the idea of setting up IIT-like institutions dedicated to basic sciences. Their recommendations were later taken up by the then Science Advisory Council to the PM (SAC-PM) headed by C.N.R. Rao, whose presentation of the concept to prime minister Manmohan Singh during the UPA-1 regime resulted in the setting up of a chain of institutions called the Indian Institutes of Science Education and Research (IISERs).
As the PSA to the government of India – in which position Chidambaram served for a long tenure of 17 years working with three different prime ministers – he launched initiatives such as Rural Technology Action Group (RuTAG), which empowered rural communities through innovative technologies, Society for Electronic Transactions and Security (SETS), to contribute towards advancing India’s cybersecurity and hardware security infrastructure, and National Knowledge Network (NKN) to connect educational and research institutions across the country.
Around 2005, concerned with the inappropriate publications-centric quantitative measure of basic research activity in the country that was being used by analysts to compare India with other countries, particularly China, Chidambaram as the PSA initiated projects for evolving other metrics for progress of S&T in the country which would also include quantitative measures of activities in patenting, mission- and industry-oriented research, agricultural and rural development, country-specific innovations, research and high-technology development.
In Chidambaram the nation has lost a highly capable and versatile scientist who had country’s development foremost in his mind. He kept science and politics (including that within the S&T apparatus of the country) apart and was thus acceptable to politicians of different hues. It is because of this non-controversial nature of his that he could easily serve under different prime ministers and succeeded in doing his bit for the development of the country.
R. Ramachandran is a science writer.
