Rajagopala Chidambaram: The Physicist Behind Two Nuclear Tests

One number was too sensitive to ever publish. It was the equation of state of plutonium, and Rajagopala Chidambaram calculated it. That work shaped the design of India’s first nuclear device. It also kept him at the centre of India’s atomic energy establishment for six decades.

Must Know

• Rajagopala Chidambaram (11 November 1936 – 4 January 2025) was an Indian physicist central to the country’s nuclear weapons programme.
• He studied at Presidency College, Chennai, then earned his PhD from the Indian Institute of Science (IISc), Bangalore, in 1962. He joined the Bhabha Atomic Research Centre (BARC) the same year.
• In 1974, he was part of BARC’s core team that designed India’s first nuclear device, tested at Pokhran as “Smiling Buddha” on 18 May 1974. Raja Ramanna led that team’s scientific work; Chidambaram’s specific contribution was calculating the equation of state of plutonium, a key design input.
• He became Director of BARC in 1990. From 1993 to 2000, he was Chairman of the Atomic Energy Commission (AEC) and Secretary, Department of Atomic Energy (DAE) — succeeding P.K. Iyengar, and later succeeded by Anil Kakodkar.
• As AEC Chairman, he led the DAE team that designed the nuclear devices for the Pokhran-II tests of May 1998. These were known as Operation Shakti, conducted jointly with the DRDO.
• He served as Principal Scientific Adviser (PSA) to the Government of India from 2001 to 2018. He was the second person to hold the post, after Dr. A.P.J. Abdul Kalam.
• He was awarded the Padma Shri in 1975 and the Padma Vibhushan in 1999.

Good to Know

• His PhD research at IISc was in Nuclear Magnetic Resonance (NMR). He later became a pioneer of high-pressure physics and crystallography research in India, work that continued alongside his nuclear-programme role.
• He chaired the Board of Governors of the International Atomic Energy Agency (IAEA) during 1994-95, a position rarely held by an Indian scientist.
• As PSA, he served across four Presidents (Kalam, Patil, Mukherjee, Kovind) and three Prime Ministers (Vajpayee, Manmohan Singh, Modi). He was succeeded as PSA by K. Vijayraghavan in 2018.
• Among his initiatives as PSA was the National Knowledge Network, linking around 1,500 educational and research institutions. He also helped set up the Rural Technology Action Groups (RuTAGs), applying science and engineering to rural problems.
• He held more than 200 research publications in refereed journals, all based on work carried out in India.
• He died in Mumbai on 4 January 2025, at the age of 88.

Test Yourself

Please wait…

1. What specific technical contribution is Rajagopala Chidambaram best known for in India’s 1974 nuclear test?

Building the Trombay plutonium plant

Calculating the equation of state of plutonium

Serving as the test’s overall scientific director

Negotiating the test site’s location

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Great to Know

• Two different roles shaped Pokhran-I. Raja Ramanna led the direct scientific team at BARC. Chidambaram was a key member of that team, not its chief. See SciTech0087 — Homi Sethna, whose own AEC chairmanship gave the 1974 test its separate, institutional leadership.
• By 1998, Chidambaram held the AEC Chairman’s post himself, the same institutional role Sethna had held in 1974. This time, he combined that role with direct leadership of the device-design team.
• His immediate successor as AEC Chairman was Anil Kakodkar, who also has his own track record on both nuclear tests. See SciTech0077 — Anil Kakodkar.
• The equation of state of plutonium describes how the metal behaves under the extreme pressures inside an implosion-type nuclear device. Getting it right was essential to the 1974 device’s design.
• He is not related to the politician P. Chidambaram, a former Union Finance and Home Minister. The shared surname is a coincidence, not a family connection.