India's Pursuit of Nuclear Weapons

Andy Zhao
May 24, 2016

Submitted as coursework for PH241, Stanford University, Winter 2016

Peaceful Beginnings

Fig. 1: Homi J. Bhabha. (Source: Wikimedia Commons)

At India's conception in 1947, Prime Minister Nehru began an ambitious nuclear program to bring prestige and inexpensive electricity to India. [1] India's nuclear program began as a peaceful push for inexpensive energy, but the nuclear fuel for the reactors also produced plutonium for a potential nuclear weapon. With the assistance of Canada and the United States, a Pressurized Heavy Water Reactor (PHWR) was built that bombarded U-238 with neutrons to chain react to form Pu-239. The CIRUS reactor was built in 1960 with international aid with the intention that it was solely for peaceful energy use even though the plutonium byproducts would be potent bomb fuel. [2] Building this PHWR was the first step in a 3-phase program planned by Dr. Homi J. Bhabha (see Fig. 1) that would eventually exploit India's large thorium reserves for civilian energy. Bhabha, a Cambridge trained physicist that worked under the scientific giants Dirac and Bohr, was the visionary of India's nuclear program. In 1958, Bhabha claimed India had the capability to build a nuclear bomb within 18 months of the decision (2 years before France and 6 years before China had the capability). In 1972, the signal was given to the scientists and engineers to build the bomb, which culminated in India's nuclear test of 1974. [3]

Bhabha's Three Phase Program

Bhabha envisioned a three-stage plan for India's civilian nuclear program that also kept the nuclear weapons option open:

  1. Pressurized Heavy Water Reactors (HWR) were used to generate electricity by bombarding naturally mined U-238 with neutrons - leaving Pu-239 as a byproduct of the fission reaction. This was preferable to a Light Water Reactor, which would have required enriched uranium. India received assistance from Canada with the finished HWR CIRUS reactor in 1960 and heavy water from the U.S. on conditions that the reactor would only be used for peaceful purposes. [2] However the plutonium from the CIRUS reactor was diverted to India's bomb detonated in 1974. Bhabha decided in 1958, while CIRUS was being constructed, to build the Phoenix reactor that would be used to extract the plutonium from the spent fuel using the PUREX process developed by the U.S. and declassified under Atoms for Peace. [1]

  2. Fast Breeder Reactors (FBR) utilize the Pu-239 from the first stage to create more fissile material than they consume. A mixed-oxide fuel is produced and reacted with enriched uranium to create more Pu-239. After enough Pu-239 is gathered, thorium will be used in the reactor to produce U-233. [4]

  3. Advanced Heavy Water Reactors utilize U-233 and India's vast thorium reserves to create significant amounts of energy for the country. Other options existed as well, but the ultimate goal was to exploit the country's thorium reserves to produce cheap, sustainable energy for the nation. [4]

Expanding Nuclear Program

Bhabha executed his plan without any domestic opposition and full support from Prime Minister Nehru. India's Atomic Energy Commision's (AEC) budget increased from 1954 to 1956 by 12 times; by 1958, AEC acquired 27% of all government investment in research and development, creating one of the world's largest teams of nuclear scientists and engineers, sending 1,104 Indian scientists to get trained at Argonne Laboratory School of Nuclear Science and Engineering from 1955 to 1974 (when the U.S. began to declassify thousands of reports, including papers on plutonium separation). [1]

Bhabha prevented the International Atomic Energy Agency (IAEA) from interfering with his Three Phase Program (that kept the military option open). The international community wanted to ensure that resources were not being diverted to militarize countries' nuclear programs. However, Bhabha revised a statute to prevent interference in the economic development of states and cited how linked India's nuclear program was to India's economy. There was no resistance from the IAEA or domestically over Bhabha's nuclear stance. Parliament was silent in discussing India's nuclear weapon option. [1]

Indian scientists were able to secretly push towards a nuclear explosion, which demonstrates the lack of military and Parliamentary involvement. In 1968 scientists began to design the device used in the Pokhran explosion in 1974 without any direction, not even from Prime Minister Indira Gandhi. [1] During this secret phase of operation, Rajagopala Chidambaram was tasked to derive the equation of state for plutonium to find how the density of plutonium related to temperature and pressure. This knowledge was essential to achieving a critical mass during symmetric compression of plutonium to get a fission chain reaction. Further, the construction of the Purinma reactor that began in 1970 was commissioned by the AEC under the guise of a fast breeder reactor. The true reason behind Purinma was to reconfirm the fast fission cross-section data of Pu-239 since the published data by the U.S. was not trusted. [1]

Peaceful Nuclear Explosion and Weaponization

In 1972, Prime Minister Indira Gandhi authorized developments for a Peaceful Nuclear Explosion (PNE). And in May 1974, the PNE was detonated in Pokhran and it was the culmination of India's entire nuclear program up until that point. Subsequent nuclear testing and weaponization was not a priority after the PNE because bomb building was not Indira Gandhi's purpose for the PNE . After the PNE, India was extremely slow to further develop its nuclear weapons capability. Canada felt betrayed and cut India off from further nuclear assistance. This led India to fully transition into a self-sufficient homegrown nuclear program without international aid. While the nuclear scientists wanted to conduct further tests, Indira Gandhi saw the marginal benefits for India's security were not worth the mounting costs and backlash. India would not test another nuclear explosion for twenty-four years. The final push for weaponization did not gain momentum until the late 1980's. Historical evidence shows that Indian policy planners were acutely aware by the spring of 1988 that the window of opportunity for preventing Pakistani nuclearization had closed. And instead of practiced restraint, there was urgency among them to bring weapons online. [5] India elected to weaponize their nuclear devices in 1989, but the process of integrating them with aircraft delivery system took until about 1994-1995. There were significant technical hurdles to overcome since India's nuclear program was never tied to the military that controlled the delivery systems. India's nuclear compartmentalization caused the Air Force to purchase French Mirage combat aircraft without understanding the challenges of a nuclear device being on board. [5]

India's Current Nuclear Status

India's nuclear program is unique because it has been so separate from military and legislative structures in India. This severance has ultimately led to an autonomous domestic nuclear program, but it has come at the cost of international segregation and inadequate nuclear power plants due to the lack of support from international nuclear bodies. In January 2015, India sought to join the Nuclear Suppliers Group (NSG) with the support of the U.S. While India seeks to be brought into the international nuclear order, they still have not signed the Nuclear Non-Proliferation Treaty or the Comprehensive Test Ban Treaty as they continue to produce fissile materials in their reactors and rely on nuclear weapons for their national security. [6] India's current nuclear capacity includes 21 reactors with 5789 MW in operation (by the end of March 2014, nuclear energy was 1.68% of India's energy capacity), 1000 MW under commissioning, and 2800 MW under construction. [7]

© Andy Zhao. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] G. Perkovich, India's Nuclear Bomb: The Impact on Global Proliferation (University of California Press, 1999)

[2] R. Rajaraman, "Estimates of India's Fissile Material Stocks," Science and Global Security, 16, 74 (2008),

[3] O. Marwah, "India's Nuclear and Space Programs: Intent and Policy," International Security 2, No. 2, 96 (Fall 1977).

[4] S. Parekh, "India's Three Stage Nuclear Program. Physics 241, Stanford University, Winter 2014.

[5] G. Kampani, "New Delhi's Long Nuclear Journey," Int. Security 38, No. 4, 79 (Spring 2014.

[6] B. Karnad, India's Nuclear Policy (Praeger Security International, 2008).

[7] Central Statistics Office, Government of India Energy Statistics 2015. March 2015.