This annotated chronology is based on the data sources that follow each entry. Public sources often provide conflicting information on classified military programs. In some cases we are unable to resolve these discrepancies, in others we have deliberately refrained from doing so to highlight the potential influence of false or misleading information as it appeared over time. In many cases, we are unable to independently verify claims. Hence in reviewing this chronology, readers should take into account the credibility of the sources employed here.

Inclusion in this chronology does not necessarily indicate that a particular development is of direct or indirect proliferation significance. Some entries provide international or domestic context for technological development and national policymaking. Moreover, some entries may refer to developments with positive consequences for nonproliferation.

Early 1955
Members of the US Joint Committee on Atomic Energy visit India to promote the expansion of peaceful applications of atomic energy. This meeting paves the way for an Indo-US agreement under which the United States agrees to supply India with heavy water to moderate the planned Canada-India Reactor, also known as the Canada-India Reactor, U.S., or CIRU.S. This agreement is reached to hedge the possibility that India's own Nangal heavy water plant may fail to operate sufficiently. Under this agreement, the United States sells India ten tons of heavy water. [Note: CIRU.S., now commonly written as Cirus, is a 40MW research reactor that is fueled with metal uranium and moderated with heavy water. Reliance on this type of fuel necessitates irradiating the fuel for a relatively brief period of time before its removal. The process of "low burn up" results in the production of significant quantities of weapons-grade plutonium. The plutonium reprocessed from the CIRU.S. reactor's spent fuel was used in India's first nuclear device test in May 1974.]
—Roberta Wohlstetter, "The Buddha Smiles:" Absent-Minded Peaceful Aid and the Indian Bomb (Los Angeles: Pan Heuristics, 1977), p. 32; K.K. Pathak, Nuclear Policy of India (New Delhi: Gitanjali Prakashan, 1980), p. 49; George Perkovich, India's Nuclear Bomb: The Impact on Global Proliferation (Berkeley, CA: University of California Press, 1999), p. 29.

15 January 1955
Dr. H. Bhabha writes Sir Crockcroft about the fruits of British-Indian cooperation in the development of nuclear reactors. He states "one might be in a position to discuss seriously an atomic power station for India by the middle of 1956 and if things develop as expected, it might be possible to have such a power station in operation in India by 1962."
—Itty Abraham, The Making of the Indian Atomic Bomb (London: Zed Books, 1998), p. 85.

February 1955
The Atomic Energy Commission of the United States agrees to sell ten tons of heavy water to India for use in the nuclear research reactor under construction at Trombay.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), pp. 89-90.

29 March 1955
Indian defense minister, Dr. Katji, declares before the parliament that "There has been a great deal of talk about nuclear weapons, atomic energy and all that. We do not want them. Our whole foreign policy is based on it. We hate bombs, atom bombs and hydrogen bombs and it would be ridiculous, I suggest, for India with its declared policies and its very limited resources to think on these lines at all."
—Lok Sabha Debates, Vol. 2, Part 2, 29 March 1955, col. 3599, in Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 93.

July-August 1955
Prime Minister Nehru persuades the leaders of the international community to elect Dr. H. Bhabha as president of the first UN Conference on the Peaceful Uses of Atomic Energy, which takes place in Geneva in July-August. This conference facilitates the dissemination of newly declassified papers containing technical information on atomic energy. In his paper submitted to the Conference, Dr. H. Bhabha delineates the basic strategy for the Indian atomic energy program. This paper argues that, although the limited resources for conventional power in India would be sufficient to maintain industrialization over the next few decades, they would not suffice to maintain a standard of living on par with the most industrially advanced nations. He claims that atomic power stations would be competitive with thermal power stations in remote areas due to the high cost of transporting coal, which is contributing to the already overburdened transportation industry. Dr. H. Bhabha reaches the conclusion that "the necessity of obtaining enriched or pure nuclear fuel (plutonium- or uranium-233) for use in future atomic power stations of a more advanced design required the setting up during the next decade of a few atomic power stations designed to produce these materials as well as electric power. Such stations should be most economically located in areas of the country remote from the coal fields, where there is an urgent demand for power which cannot be met in time from hydroelectric sources." The conference is widely regarded as paving the way for US, Canadian, and British assistance for India's fledgling nuclear power program.
—George Perkovich, India's Nuclear Bomb: The Impact on Global Proliferation (Berkeley, CA: University of California Press, 1999), p. 30; Homi Jehangir Bhabha: Collected Scientific Papers, B.V. Sreekantan, Virendra Singh, and B.M. Udgaonkar, eds. (Bombay: Tata Institute of Fundamental Research, 1985), p. LXIII.

August 1955
Canada offers to build a 40MW research reactor, the CIRU.S., in India. The Canadian offer is made as part of the Colombo plan. Canada also offers to pay all the foreign exchange costs of building the $14 million reactor (the ultimate cost of the reactor is $24 million). Ottawa attaches no strict safeguards on the use of the plutonium produced by the reactor, other than the commitment by India, via a secret annex to the agreement, that the reactor and fissile materials it produces would be used only for peaceful purposes. [Note: The Colombo plan was an initiative created at the Commonwealth Conference on Foreign Affairs held in Colombo, Ceylon (now Sri Lanka) in January 1950. The aim of this Conference was to exchange views on the needs of Asian countries. As a result of this meeting, a Consultative Committee was established to assess the needs, available resources, and to create a framework though which international cooperation could be promoted to assist countries in raising their standard of living. In addition to donations and assistance provided by wealthier Commonwealth nations, developing member countries were also encouraged to become donors and participate in economic and technical cooperation programs. Initially extended at five-year intervals, the meeting of the Consultative Committee in Jakarta in 1980 decided to extend the plan indefinitely.]
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 92; Brahma Chellaney, Nuclear Proliferation: The US-India Conflict (New Delhi: Orient Longman, 1993), p. 6.

October 1955
The United Kingdom Atomic Energy Commission declares that it would be willing to lend India all of the fuel elements necessary for the reactor being constructed at Trombay. The United Kingdom also pledges assistance for the Zerlina zero energy reactor and with new designs for future reactors.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), pp. 91-92.

1955
Physicist Isador Rabi, chairman of the US Atomic Engery Commission's General Advisory Committee, conveys his concerns about India's intentions in a discussion with the US State Department's atomic energy adviser, Gerard Smith. Chairman Rabi states that safeguards must be instated prior to operating the reactors that are constructed abroad. He believes that the US manufacturers had not considered this problem and that even a country like India could construct weapons once it was able to produce plutonium.
—Smith memorandum for file, September 14, 1955, Foreign Relations of the United States 1955-1957, vol. 20, p. 1981, cited in Peter A. Clausen, Nonproliferation and the National Interest (New York: HarperCollins College, 1993), p. 34; George Perkovich, India's Nuclear Bomb: The Impact on Global Proliferation (Berkeley, CA: University of California Press, 1999), p. 31.

1955
India begins implementation of Dr. Bhabha's three-stage atomic energy plan with the construction of the Apsara research reactor, located at Trombay. The design for this reactor is based on British engineering drawings. [Note: Apsara was the first nuclear reactor in Asia (outside of the Soviet Union) to go critical.]
—Itty Abraham, The Making of the Indian Atomic Bomb (London: Zed Books, 1998), p. 85.

1955
The United States begins training foreign nuclear scientists and engineers and declassifying "thousands" of papers and reports on matter such as plutonium reprocessing. India avails itself to both forms of assistance.
—Roberta Wohlstetter, "The Buddha Smiles": Absent-Minded Peaceful Aid and the Indian Bomb (Los Angeles: Pan Heuristics, 1977), p. 30.

1955
Dr. Bhabha proposes to Prime Minister Nehru that India publicly renounce nuclear weapons. In response, Nehru says that the discussion should be continued "on the day when India was ready to produce one."
—Bertrand Goldschmidt, The Atomic Complex (La Grange Park, Ill.: American Nuclear Society, 1982), p. 185.

16 March 1956
The United States makes a contract to sell India heavy water for the CIRU.S. Reactor. The agreement states that "the heavy water sold hereunder shall be for use only in India by the government in connection with research into and the use of atomic energy for peaceful purposes..." Under this contract, the United States would provide four shipments of heavy water, the last of which is scheduled for 15 June 1956.
—Brahma Chellaney, Nuclear Proliferation: The US-India Conflict (New Delhi: Orient Longman, 1993), p. 36.

28 April 1956
India and Canada sign a nuclear cooperation agreement. Under the agreement, Canada agrees to supply half the initial uranium fuel required for the CIRU.S. research reactor.
—Brahma Chellaney, Nuclear Proliferation: The US-India Conflict (New Delhi: Orient Longman, 1993), p. 6.

4 August 1956
India commissions its first nuclear research reactor, Apsara.
—Department of Atomic Energy, Government of India, "Brief Annual Report: 1962-63," p. 2.

10 August 1956
In a letter to President Eisenhower, the US Atomic Energy Commission (AEC) Chairman Lewis Strauss writes that Dr. Bhabha considers US proposals to strengthen safeguards "as more or less an insult to India's peaceful intentions." Chairman Strauss suggests that the United States should accept current safeguards provisions to preserve its role as supplier to India.
—Lewis Strauss to President Eisenhower, August 30, 1956, p. 2, Joint Committee on Atomic Energy Files, International Affairs, India, National Archives.

27 September 1956
At a conference on the International Atomic Energy Agency (IAEA) Statute, Dr. Bhabha declares, "We consider it to be the inalienable right of States to produce and hold the fissionable material required for the peaceful power programs." To bolster his critique of safeguards Dr. Bhabha argues that since technologically advanced states, especially those who already possess nuclear weapons, would not need assistance, they would not be subject to safeguards. He says "We will stand on the brink of a dangerous era sharply dividing the world into atomic 'haves' and 'have nots' dominated by the Agency." Commenting on the dual-use nature of nuclear power, Bhabha says, "[T]here are many States, technically advanced, which may undertake with Agency aid, fulfilling all the present safeguards, but in addition run their own parallel programs independently of the Agency in which they could use the experience and know-how obtained in Agency-aided projects, without being subject in any way to the system of safeguards."
—Statement by Homi Bhabha at the Conference on the IAEA Statute, 27 September 1956, in J.P. Jain, Nuclear India, vol. 2 (New Delhi: Radiant, 1974), pp. 44-46.

23 October 1956
The IAEA Statute is signed. The final statute requires only that agency safeguards apply to fissile materials and relevant reactors to ensure that they are not diverted for military use. States are allowed to separate and maintain possession of the plutonium that is produced, under safeguards when applicable.
—IAEA Statute, Article XII (A.5), signed 23 October 1956, in J.P. Jain, Nuclear India, vol. 2 (New Delhi: Radiant, 1974), p. 38.

1956
In the first supply relationship between the United States and India, the United States agrees to sell 18.9 metric tonnes of heavy water to moderate the CIRU.S. research reactor. As with the Canadian agreement to build the reactor and supply half of the uranium, the United States does not require formal safeguards.
—Brahma Chellaney, Nuclear Proliferation: The US-India Conflict (New Delhi: Orient Longman, 1993), p. 6.

1956
The Indian delegation to the UN proposes an amendment to the draft statute for the IAEA based on two concerns previously voiced by India's UN representative, V.K. Krishna Menon: (1) that countries such as India should have full say in the constitution and rule setting of an international atomic agency; and (2) the agency should not compel developing countries to assume the role of raw material supplier while it controls reactor operations, reprocessing, "and so forth." The amendment reads: "That the inspection and safeguard provisions should be reasonable and ensure that any aid given by the Agency is not used directly for furthering a military purpose. The inspection and safeguards should not, however, be so rigorous as to give the Agency a hold on the economic life of the country through control of fissionable material or lead to the development of an unhealthy situation in which States in the world receiving aid from the Agency are put into a different class from those who do not go to the Agency for aid."
—Krishna Menon, statements to the First Committee of the United Nations, 17, 22-23 November 1954, reprinted in J.P. Jain, Nuclear India, vol. 2 (New Delhi: Radiant, 1974), pp. 4-12, 37-38.

20 January 1957
In a speech delivered at the Atomic Energy Commission (AEC) in Trombay, Dr. H. Bhabha calls for power reactors to also be used for the production of fuel to be used in future reactors. He remarks, "It is likely that in the future more advanced and efficient types of atomic power stations will use concentrated atomic fuel, such as uranium-235, uranium-233, or plutonium, rather than the naturally occurring uranium. If we are not to depend on the import of such fuel from abroad, and not to build a gaseous diffusion plant involving an enormous expenditure and technical effort, it is necessary for us to start producing this fuel now by converting natural uranium into plutonium, and thorium into uranium-233 in atomic reactors. If we are therefore, not to lose further ground in the modern world, it is necessary for us to set up some atomic power stations within the coming five years, which will produce plutonium for our future power reactors, in addition to producing electricity now."
—B.V. Sreekantan, Virendra Singh, and B.M. Udgaoankar, eds., Homi Jehangir Bhabha: Collected Scientific Papers (Bombay: Tata Institute of Fundamental Research, 1985), p. 975.

20 January 1957
Prime Minister Nehru states that "whatever the circumstances, we shall never use this atomic energy for evil purposes. There is no condition attached."
—Nehru quoted in G.G. Mirchandani, India's Nuclear Dilemma (New Delhi: Popular Book Services, 1968), p. 230.

27 February 1957
In an attempt to improve Indo-US relations, Eisenhower administration officials decide to "actively encourage India to [consider] US offers for bilateral assistance in the atomic reactor field," emphasizing the decision to declassify information related to nuclear power reactors. The also propose training programs for Indian atomic energy specialists.
—US National Security Council, Operations Coordinating Board, memorandum, "Outline Plan of Operations with Respect to India and Nepal," February 27, 1957, p. 1, in US Nuclear Non-Proliferation Policy, 1945-1991, ed. Virginia I. Foran (Alexandria, Va.: National Security Archive/Chadqyck-Healy, 1991), no. 00290.

24 July 1957
During a discussion on the Department of Atomic Energy (DAE) budget at the Lok Sabha (lower house of parliament), Prime Minister Nehru indicates that the budget for atomic energy "increased twelve-fold" between 1954 and 1956.
—Lok Sabha Debates, 2d ser., July 24, 1957, col. 4949.

24 July 1957
Prime Minister Nehru makes a speech before the Lok Sabha (lower house of parliament) disavowing an interest in producing nuclear weapons. He says, "we are not interested in making atom bombs, even if we have the capacity to do so, and that in no event will we use atomic energy for destructive purposes." However, he closes his speech by indicating that the future is in the hand of the international community by saying that "if one has these fissionable materials and if one has the resources, then one can make a bomb, unless the world will be wise enough to come to some decision to stop the production of such bombs."
—Lok Sabha Debates, 2d ser., July 24, 1957, col. 4954.

August 1957
The Department of Atomic Energy (DAE) establishes a "Training School" to train nuclear scientists and engineers in various disciplines. According to the DAE's Annual Report for 1956-57, 300 scientists and engineers were employed at Trombay. In addition, the Atomic Energy Commission (AEC) begins its own training project at Trombay. In its first year, the training school admits 250 graduate scientists and engineers for year-long courses in physics, chemistry, metallurgy, and engineering.
—Department of Atomic Energy, Government of India, "Brief Annual Report: 1962-63," p. 11; Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 98.

1957
A "small" plant for domestic fabrication of heavy water is commissioned.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 101.

30 January 1958
Prime Minister Nehru speaks about how India would respond if nuclear weapons were stationed in Pakistan or another Asian country. He says, "We have the technical know-how for manufacturing the atom bomb. We can do it in three or four years if we divert sufficient resources in that direction. But, we have given the world an assurance that we shall never do so. We shall never use our knowledge of nuclear science for purposes of war."
—G.G. Mirchandani, India's Nuclear Dilemma (New Delhi: Popular Book Services, 1968), p. 231.

24 March 1958
Prime Minister Nehru announces in the Lok Sabha (lower house of parliament) that the government is considering a 15-year plan for the development of nuclear energy in India. Details of this plan are never published.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 101.

July 1958
Prime Minister Nehru authorizes project Phoenix, a plan to build a spent fuel reprocessing plant with a capacity to reprocess 20 tons of fuel a year, which is calculated to match the production capacity of CIRU.S.
—India's Nuclear Weapons Program, "The Beginning: 1944-1960," <http://www.fas.org/nuke/hew/India/IndiaOrigin.html>.

6 September 1958
In a statement before the Second International Atomic Energy Agency (IAEA) General Conference, Dr. Bhabha asserts that either a 150 or 250MW nuclear power station could easily function at a "high load factor" as part of the Bombay power grid. Dr. Bhabha assumes that Indian nuclear plants will operate at 80 percent load factors.
—J.P. Jain, Nuclear India, vol. 2 (New Delhi: Radiant, 1974), p. 87; Roberta Wohlstetter, "The Buddha Smiles": Absent-Minded Peaceful Aid and the Indian Bomb (Los Angeles: Pan Heuristics, 1977), p. 48.

November 1958
In an article in the Economic and Political Weekly of Bombay, British economist I.M.D. Little examines Dr. Bhabha's assertions about the economic feasibility of nuclear power in India. Little concludes that nuclear plants would not be "economically advantageous" in India.
—I.M.D. Little, "Atomic Bombay? A Comment on 'The Need for Atomic Energy in the Underdeveloped Countries'," Economic and Political Weekly (Bombay), November 29, 1958, p. 1483, cited in Wohlstetter, "The Buddha Smiles," pp. 46-47.

1958
The Indian government formally adopts the three-stage nuclear power plan for India's economic development. [Note: The three-stage plan was outlined by Dr. Bhabha at the Conference on the Development of Atomic Energy for Peaceful Purposes in New Delhi in November 1954.]
—G. Venkataraman, Bhabha and His Magnificent Obsessions (Hyderabad: Universities Press India, 1994), p. 158.

Late 1958
The activities of the Trombay Atomic Research Centre are divided into six divisions: (1) the education and training division, which is responsible for overseeing the training school and awarding grants for nuclear research to outside educational institutions; (2) the production division, which is in charge of the uranium metal plant to convert "uranium concentrates" into nuclear metal scheduled to commence operation in 1959, a fuel fabrication plant to produce fuel elements for all the reactors also scheduled to come on line in 1959, and a plutonium extraction plant to remove plutonium from the reactors and separate it from the uranium fuel elements through a chemical process; (3) the research division, in charge of physics, chemistry, radio-chemistry, reactor control and electronics sections; (4) the engineering division, which oversees a metallurgy section that conducts work on nuclear materials and the fabrication of fuel elements, a reactor engineering section and a chemical engineering section; (5) the biology and medical group, which researches the effects of atomic radiation; and (6) the atomic minerals division, which assumes the responsibility for atomic mineral surveying and prospecting in its entirety.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), p. 99.

1958 and 1959
The Indian government spends 27 percent of its research and development budget on the Atomic Energy Commission (AEC), which receives 77.6 million rupees in 1958 and 1959.
—Itty Abraham, "India's 'Strategic Enclave': Civilian Scientists and Military Technologies," p. 242.

10 March 1959
During the annual debate on the Department of Atomic Energy (DAE), two members of parliament introduce motions calling for discussion of India's need to expand nuclear research for defensive purposes. The impetus for such proposals stems from Chinese statements made in mid-1958 about their determination to produce nuclear weapons. Prime Minister Nehru responds by assuring parliament that India's nuclear research is "more advanced and more widespread" than all nations, with the exception of the advanced powers.
—G.G. Mirchandani, India's Nuclear Dilemma (New Delhi: Popular Book Services, 1968), pp. 12-13.

November 1959
A team of American researchers concludes that the operating costs of nuclear plants in India that are located far from coal fields would be similar to the operating costs of conventional power plants at the same locations. However, the construction costs for nuclear plants would greatly exceed those of conventional plants.
—Atomic Energy Commission, memorandum of record, November 13, 1959, pp. 1-2, Joint Committee on Atomic Energy files, International Affairs, India, National Archives.

December 1959
The Indian parliament's Consultative Committee on Atomic Energy holds a private meeting at which it discusses the possibility of China obtaining a nuclear weapon. During this discussion Dr. Bhabha expresses his view that India's nuclear program has developed to the point where India could indigenously produce nuclear weapons.
—G.G. Mirchandani, India's Nuclear Dilemma (New Delhi: Popular Book Services, 1968), p. 13.

1959
According to the Department of Atomic Energy (DAE) Annual Report for 1958-59, the number of scientists and engineers working at Trombay has doubled since the last report to approximately 700. The formation of working groups in engineering, chemistry, radio chemistry, medical health, and biology has contributed to this increase. In addition, the number of graduate scientists and engineers admitted to the Trombay training institute has increased to 350.
—Shyam Bhatia, India's Nuclear Bomb (Ghaziabad: Vikas, 1979), pp. 98-99.

1959
The atomic energy facilities at Trombay employ over 1,000 scientists and engineers by 1959.
—Homi Bhabha, statement at the Third IAEA General Conference, September 25, 1959, in J.P. Jain, Nuclear India, vol. 2, p. 91.