Pakistan demonstrated its resolve and capability by conducting six nuclear tests on May 28 in response to India’s tests on May 11 and 13 in 1998. Pakistan succeeded in responding to India’s nuclear challenge in 1998 due to two decades of sustained effort and the dedication of thousands of scientists and engineers in Pakistan Atomic Energy Commission (PAEC) and Khan Research Laboratories (KRL) who worked with selfless devotion in the face of seemingly insurmountable odds and technology denials.

It is widely believed that the most difficult step in manufacturing a nuclear device is the production of nuclear fuel or fissile material for nuclear weapons. There are two types of fissile materials (weapons-grade highly enriched uranium and weapons-grade plutonium, although any combination of plutonium isotopes (including reactor-grade plutonium) can be used in nuclear weapons.

What is less appreciated is that the only way to produce fissile material for nuclear weapons is through the development of the nuclear fuel cycle. A country that wishes to produce fuel for peaceful uses (power or research reactors) or weapons (fissile material) will first have to master the complete nuclear fuel cycle. It involves a series of sequential steps that begins with uranium exploration, mining and refining of natural uranium and its purification to 99%, production of uranium ore or yellow cake (uranium processing), and (uranium conversion) that includes the production of yellowcake into uranium oxide, metal, and conversion to natural uranium hexafluoride gas (UF-6) of very high purity. UF6 is the feedstock for an enrichment plant using gas-centrifuge technology or gaseous-diffusion technology wherein the UF6 can be enriched to any desired level (3-5%) for power reactors, and 90 % for nuclear weapons.

Pakistan’s rendezvous with the nuclear fuel cycle begins in May 1972 when the then President Zulfikar Ali Bhutto approved a long-term nuclear plan submitted by Mr. Munir A. Khan for acquiring complete control over the nuclear fuel cycle and setting up of various plants and facilities for this purpose.

A centrifuge plant without UF6 is like an oil refinery without a supply of crude oil and vice versa. A UF6 production plant and a centrifuge plant, therefore, are the two integral components required for a successful uranium enrichment program. However, if a country wishes to produce plutonium, it does not require uranium enrichment but the fabrication of natural uranium fuel for a heavy water production reactor that yields weapons-grade plutonium. This is then separated in a fuel reprocessing plant that forms the back end of the nuclear fuel cycle. A common misconception is that the two routes to a bomb for producing fissile material (enriched uranium route and plutonium route) are mutually exclusive. When a country is able to acquire complete mastery over the complete nuclear fuel cycle, it can simultaneously pursue both routes and produce highly enriched uranium and plutonium for nuclear weapons.

Pakistan reorganized its fledgling nuclear program in the immediate aftermath of the separation of East Pakistan in December 1971 and in anticipation of India’s development of nuclear capability. The country’s leadership had to respond to the external strategic challenges posed by India’s conventional forces and its growing nuclear potential. This was a herculean task confronting Pakistan’s determined scientific and engineers who were exhorted to the challenge by President Zulfikar Ali Bhutto on January 20, 1972 in Multan where he appointed Mr. Munir A. Khan as the new chairman of PAEC (1972-1991) who was working as head of Reactor Engineering and Fuel Cycle in the IAEA. They had already forged a consensus for acquiring nuclear technology for defence and development after the 1965 India-Pakistan war. Mr. Bhutto placed PAEC directly under his control and its new chairman would now report directly to the country’s chief executive—an arrangement that continued until the formation of the National Command Authority in 2000.

The nuclear program in 1972 comprised a 5 MW Pakistan Atomic Research Reactor-1 around which the Pakistan Institute of Nuclear Science and Technology (PINSTECH) was established during the 1960s. The 137 MW Karachi Nuclear Power Plant (KANUPP) was the first nuclear power plant in Pakistan and the Muslim world that was approaching completion. This civilian infrastructure was built under Dr. I. H. Usmani (chairman PAEC 1960-1972) and half of the manpower trained during this period left for Bangladesh in 1971. The total remaining trained nuclear workforce related to various disciplines including scientists, engineers and technicians at the beginning of 1972 was 283. More importantly, no nuclear fuel cycle infrastructure and facilities existed in the country and Pakistan had to develop nuclear capability by any means after 1971 for national survival.

Pakistan’s rendezvous with the nuclear fuel cycle begins in May 1972 when the then President Zulfikar Ali Bhutto approved a long-term nuclear plan submitted by Mr. Munir A. Khan for acquiring complete control over the nuclear fuel cycle and setting up of various plants and facilities for this purpose. Pakistan’s initial strategy was to acquire the necessary fuel cycle facilities through international cooperation under IAEA safeguards, train manpower and then build similar plants outside safeguards for the nuclear option. Agreements were signed with France for a reprocessing plant, Canada for a fuel fabrication plant, West Germany for a heavy water plant, all under IAEA safeguards. But India’s nuclear test in May 1974 using plutonium produced in the Canadian-supplied CIRUS research reactor that employed US-origin heavy water, resulted in the formation of an export control cartel—the Nuclear Suppliers Group in 1975—to curb the misuse of the supply-side of civilian nuclear technology for weapons purposes. While India had committed the original sin, Pakistan now had to face the consequences that became apparent almost immediately when all the supplier states unilaterally cancelled agreements for the supply of fuel cycle facilities under IAEA safeguards.

Pakistan was asked to open its entire nuclear program for international inspections and sign the NPT for implementation of agreements signed before India’s May 1974 test. It was clear that Pakistan would have to complete the nuclear fuel cycle outside safeguards without foreign assistance and acquire the capability to produce fissile material for nuclear weapons. In the wake of India’s 1974 nuclear test, Prime Minister Bhutto convened a meeting of the Defence Committee of the Cabinet on June 15, 1974 and issued formal directives to PAEC to expedite work on the fuel cycle and the nuclear device simultaneously. Two months before India’s 1974 test, the chairman PAEC had set up the Directorate of Technical Development (DTD) with the mandate to coordinate the work of the various specialized groups required to produce a nuclear device. A theoretical physics group had already been set up in December 1972 that would complete the first indigenous design of a nuclear device by 1978.

In the wake of India’s 1974 test of a nuclear explosive device in Pokhran, PAEC immediately embarked on an ambitious multipronged approach to acquire the necessary technologies and equipment through an elaborate import procurement network established under S. A. Butt in Brussels and Paris. Work on several fuel cycle projects commenced in 1975 and within seven years, PAEC had completed several fuel cycle projects. These included a uranium processing and conversion complex in D.G. Khan; a fuel fabrication plant in Kundian, and the New Labs reprocessing plant. India’s first nuclear test spurred international nonproliferation sanctions against Pakistan and Canada abruptly terminated supplies of nuclear fuel, spare parts, and heavy water for KANUPP in December 1976. Within two years, PAEC scientists produced the first fuel element for KANUPP which was presented to the President of Pakistan by the chairman PAEC and by 1980, Pakistan began loading KANUPP with locally produced nuclear fuel. But as a responsible state, it continued to implement safeguards on Pakistani-made nuclear fuel and commissioned the New Labs reprocessing plant (outside safeguards) only after the indigenous Khushab-1 production reactor started producing plutonium in 1998. Unlike India, Pakistan did not violate any international agreements or safeguards. As part of the fuel cycle, a centrifuge enrichment laboratory was established in Chaklala in 1975 as Airport Development Workshop. It was renamed Engineering Research Laboratories (ERL) in July 1976 and made autonomous when Dr. A. Q. Khan who was earlier working for a Dutch affiliate of the URENCO consortium in the Netherlands prior to his arrival in December 1975. He was appointed ERL’s project-director in July 1976 and also directly reported to the country’s chief executive until 2001. The rest of the nuclear program, including all other fuel cycle; weapons development and testing; research, power and plutonium production reactors; reprocessing facilities; human resource development; and peaceful applications of atomic energy in medicine and agriculture remained under PAEC.

It was at the Chaklala laboratory that the first prototype centrifuge machine was developed and separated the first lab-scale samples of UF6 in 1978 followed by the setting up of a pilot-centrifuge plant in Sihala and the main facility in Kahuta by 1980-81. By 1981, PAEC had completed the fuel cycle and started supplying UF6 to the centrifuge project which was renamed KRL in 1981. Within the next few years, KRL first succeeded in producing small, and by the mid-1980s, required quantities of highly enriched uranium. The weapons-grade HEU is then handed back to PAEC that forms the core of a nuclear device.

Producing fissile material without a workable nuclear device and delivery system is akin to having a bullet without a gun. Work on developing of the nuclear device and test sites in Chaghi, Kharan and Kirana Hills continued in parallel from 1974 onwards, with various specialized groups tasked to produce the complicated trigger mechanism, high-speed electronics, precision manufacturing facilities, neutron source and explosive lenses. On March 13, 1983, PAEC conducted the first cold test (without the fissile material) of a working nuclear device. The same evening, Mr. Munir Khan informed President Zia that, “Pakistan was now ready to produce a nuclear device.” Between 1983 and 1995, another 24 cold tests were conducted that validated different weapon designs.  Once the nuclear fuel cycle was completed along with the success of the first cold tests in the early 1980s, PAEC secured President Zia’s approval for completing the last missing link in the plutonium route as part of the fuel cycle—indigenous natural uranium fueled, 50 MW Khushab-1 heavy water plutonium production reactor at the Khushab Nuclear Complex. It was initiated in 1986 and completed by 1997. Pakistan has added three more production reactors at the same site since the commissioning of Khushab-1 reactor. Plutonium enables the development of compact, powerful, and miniaturized nuclear warheads suitable for ballistic and cruise missiles and battlefield nuclear weapons, as these plutonium-based devices require five times less fissile material compared to HEU. Plutonium production also allows for the production of tritium which is used to boost nuclear warheads yields manifold and can be used in the secondary stage of thermonuclear weapons.

The efforts of the two decades paid off when Pakistan successfully responded to India’s nuclear tests on May 28, 1998 which was Pakistan’s finest hour and tested five nuclear devices that used HEU as fissile material. The DTD issued a statement after the May 28 tests in Chaghi that said that it had fulfilled its mission not only by successfully producing a variety of potential nuclear devices, but also by performing perfect hot tests that resulted in near-expected yields and provided invaluable scientific data. It added that the “tests had validated scientific theory, design and previous results from cold tests. This has more than justified the creation and establishment of DTD more than 20 years back. Through these critical years of nuclear device development, the leadership contribution changed hands from Mr. Munir Ahmad Khan to Dr. Ishfaq Ahmad (chairman PAEC 1991-2001) and finally to Dr. Samar Mubarakmand (Member Technical)”….and the PAEC as an organization had proven to be the pride of the Pakistani nation.

Although Pakistan made great strikes in the peaceful uses of atomic energy such as biotechnology, agriculture and nuclear medicine, the civilian nuclear energy program remained under international nonproliferation sanctions. The government had approved the construction of a 600 MW nuclear power plant in Chashma in 1976 where additional power reactors were to be set up under IAEA safeguards. The French reprocessing plant was also supposed to be built for separating the spent fuel of the Chashma nuclear power complex under safeguards and was approved by the IAEA Board of Governors in 1976. But it was cancelled under US pressure in 1978 and the nuclear energy program remained stalled due to lack of international support. It was only in September 1986 that an international embargo on civil nuclear energy cooperation against Pakistan was finally broken with the conclusion of the Sino-Pakistan civil nuclear deal that paved the way for installation of four Chahsma power reactors over the next two decades—all under IAEA safeguards. The agreement for the 300 MW Chashma-1 power reactor was reached in November 1989 and the contract signed in December 1991. China is now completing two 1100 MW power reactors in Karachi and Pakistan is pursuing the goal of producing 8800 MW of nuclear energy by 2030.

Pakistan has come a long way since 1998 in becoming a mature and full-fledged nuclear-weapon state. It has operationalized its nuclear deterrent under a centralized command and control structure of the National Command Authority, developed and instituted a nuclear safety and security regime and export control regulations and has revitalized the nuclear energy program. The country’s nuclear deterrent has served to maintain strategic stability and proven its worth in preventing escalation and conventional conflict in South Asia during the Kargil crisis in 1999, 2001-2002, 2008 and the 2019 Pulwama-Balakot crises. Pakistan’s strategic program continues to enjoy bipartisan national consensus and its centrality in providing an affordable and indigenous capability in the face of evolving threats is as relevant today as it was in the past, especially for ensuring a credible deterrent against India’s sustained modernization and buildup of conventional and strategic nuclear forces that are fueling destabilizing doctrines and offensive force postures to the detriment of regional peace and security.

The writer is a Senior Research Fellow, Center for Strategic International Studies Islamabad

Pakistan reorganized its fledgling nuclear program in the immediate aftermath of the separation of East Pakistan in December 1971 and in anticipation of India’s development of nuclear capability.