In the mid-1970s Pakistan embarked upon the uranium enrichment route to acquire a nuclear weapons capability. Pakistan conducted nuclear tests in May 1998, shortly after India's nuclear tests, declaring itself a nuclear weapon state. Pakistan currently possesses a growing nuclear arsenal, and remains outside both the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and the Comprehensive Nuclear Test Ban Treaty (CTBT). It also is the sole country blocking negotiations of the Fissile Material Cut-Off Treaty (FMCT).

Capabilities

Hans Kristensen and Robert Norris characterize Pakistan as having, "the world's fastest-growing nuclear stockpile." [1] According to the SIPRI 2018 Yearbook, Pakistan possesses between 150 and 160 nuclear weapons. [2] Pakistan has stockpiled approximately 3.4 ± 0.4 metric tons of highly enriched uranium (HEU), and produces enough HEU for perhaps 10 to 15 warheads per year. Pakistan also has a stockpile of about 280 kg of weapons-grade plutonium . In addition, the Chashma reprocessing plant that began operations in 2015 is thought to have expanded Pakistan’s plutonium production capability by 50-100 kg per year. [3] Pakistan has completed work on all four reactors at the Khushab facility, where the Khan Research Laboratories greatly increased its HEU production capacity. Satellite imagery of the fourth and last reactor at Khushab from January 2015 verified the complete external construction, including the presence of steam that signified its operation. [4]

History

Establishing a Nuclear Program:
1956 to 1974

Pakistan asserts the origin of its nuclear weapons program lies in its adversarial relationship with India; the two countries have engaged in several conflicts, centered mainly on the state of Jammu and Kashmir. Pakistan began working on a nuclear program in the late 1950s and the Pakistan Atomic Energy Commission (PAEC) was established in 1956. [5] President Z.A. Bhutto forcefully advocated the nuclear option and famously said in 1965 that "if India builds the bomb, we will eat grass or leaves, even go hungry, but we will get one of our own." [6] After Pakistan’s defeat in the December 1971 conflict with India, Bhutto issued a directive instructing the country's nuclear establishment to build a nuclear device within three years. [7] Although the PAEC had already created a taskforce to work on a nuclear weapon in March 1974, India’s first test of a nuclear bomb in May 1974 played a significant role in motivating Pakistan to build its own. [8]

A.Q. Khan's Contribution:
1975 to 1998

The Pakistan Atomic Energy Commission, headed by Munir Ahmad Khan, focused on the plutonium route to nuclear weapons development using material from the safeguarded Karachi Nuclear Power Plant (KANUPP), but its progress was inefficient due to the constraints of nuclear export controls applied in the wake of India's nuclear test. [9] Around 1975, A.Q. Khan, a metallurgist working at a subsidiary of the URENCO enrichment corporation in the Netherlands, returned to Pakistan to help his country develop a uranium enrichment program. [10] Having brought centrifuge designs and business contacts back with him to Pakistan, Khan used various tactics, such as buying individual components rather than complete units, to evade export controls and acquire the necessary equipment. [11] By the early 1980s, Pakistan had a clandestine uranium enrichment facility, and A.Q. Khan would later assert that the country had acquired the capability to assemble a first-generation nuclear device as early as 1984. [12]

Pakistan also received assistance from other states, especially China. Beginning in the late 1970s China provided Pakistan with various levels of nuclear and missile-related assistance, including centrifuge equipment, warhead designs, HEU, components of various missile systems, and technical expertise. [13] Eventually, from the 1980s onwards, the Khan network diversified its activities and illicitly transferred nuclear technology and expertise to Iran, North Korea, and Libya. [14] The Khan network was officially dismantled in 2004, although questions remain concerning the extent of the Pakistani political and military establishment's involvement in the network's activities. [15]

Pakistan After Nuclear Tests:
1998 to 2007

On 11 and 13 May 1998, India conducted a total of five nuclear explosions, after which Pakistan felt pressured to respond to in kind. [16] Prime Minister Nawaz Sharif decided to test, and Pakistan detonated five explosions on 28 May and a sixth on 30 May 1998. With these tests Pakistan abandoned its nuclear ambiguity and stated that it would maintain a "credible minimum deterrent" against India. [17] In 1998, Pakistan commissioned its first plutonium production reactor at Khushab, which was capable of producing approximately 11 kg of weapons-grade plutonium annually. [18]

Pakistan does not have a formally declared nuclear doctrine, so it remains unclear under what conditions Pakistan might use nuclear weapons. [19] In 2002, President Pervez Musharraf stated that, "nuclear weapons are aimed solely at India," and would only be used if "the very existence of Pakistan as a state" was at stake. Lieutenant General Khalid Kidwai, the Director General of Pakistan’s Strategic Plans Division that acts as a secretariat for the Nuclear Command Authority of Pakistan further elaborated that this could include Indian conquest of Pakistan's territory or military, "economic strangling," or "domestic destabilization." [20]

Historically, the security of Pakistan's nuclear weapons has been of significant concern to the international community. Taliban-linked groups have successfully attacked tightly guarded government and military targets in the country. Militants carried out small-scale attacks outside the Minhas (Kamra) Air Force Base in 2007, 2008, and 2009 but Pakistani officials repeatedly deny that the base is used to store nuclear weapons. [21][22] Al-Qaeda’s Abu Yahya al-Libi had also called for attacks on Pakistani nuclear facilities. Such developments increased the likelihood of scenarios in which Pakistan's nuclear security could be put at risk. Nevertheless, Pakistan has consistently asserted that it had control over its nuclear weapons, and that it was impossible for groups such as the Taliban or proliferation networks to gain access to the country's nuclear facilities or weapons. Consequently, Pakistan took measures to strengthen the security of its nuclear weapons and installations and to improve its nuclear command and control system. [23] The National Command Authority (NCA), composed of key civilian and military leaders, is the main supervisory and policy-making body controlling Pakistan's nuclear weapons, and maintains ultimate authority on their use. [24] In November 2009, then-Pakistani President Asif Ali Zardari transferred his role as head of the National Command Authority to the Prime Minister, Yusuf Gilani. [25]

Pakistan and the Nuclear Nonproliferation Community:
2008 to Present

Pakistan was critical of the U.S.-India nuclear cooperation agreement that was signed in 2008, but has also periodically sought a similar arrangement for itself. [26] In 2008, Pakistan pushed for a criteria-based exemption to the rules of the Nuclear Suppliers Group (NSG), which unlike the country-based exception benefiting only India could have made Pakistan eligible for nuclear cooperation with NSG members. Despite its reservations about the India special exception, Pakistan joined other members of the Board of Governors in approving India's safeguards agreement with the International Atomic Energy Agency (IAEA) in August 2008. [27]

In response to the U.S.-India deal, Pakistan sought to increase its civilian nuclear cooperation with China. Under a previous cooperation framework, China supplied Pakistan with two pressurized water reactors (PWR), CHASNUPP-1 and CHASNUPP-2, that entered into commercial operations in 2000 and 2011 respectively. [28] In 2009, China National Nuclear Corporation (CNNC) agreed to supply two additional 340-MW power reactors to Pakistan, CHASNUPP-3 and CHASNUPP-4. The United States voiced concerns regarding Chinese construction of these nuclear reactors at Chashma, arguing that China was violating its commitments as a Nuclear Suppliers Group (NSG) member by constructing these additional nuclear reactors. According to a report by Arms Control Association, China should have asked for an exemption from the NSG to build additional reactors because Pakistan is neither a member of the NPT nor under full-scope IAEA safeguards. [29] However, China has argued that it has no obligation to do so because the reactor transfer was based on a contract negotiated in 2003 and grandfathered in when China joined the NSG in 2004. [30] [31]

Pakistan has also strengthened its personnel reliability program (PRP) to prevent radicalized individuals from infiltrating the nuclear program, although various experts believe that potential gaps still exist. [32] Satellite imagery also shows increased security features around Khushab-4. [33] The United States has provided various levels of assistance to Pakistan to strengthen the security of its nuclear program. [34]

The heavy water and natural uranium reactors at Khushab are a central element of Pakistan's nuclear warhead plutonium and tritium production programs. It is estimated that the plutonium production capacity of Khushab-2 and Khushab-3 to be around 15 kg and 18 kg of plutonium, respectively, per year. [35] With entry into operation of the Khushab-4 reactor, it is estimated that the entire complex can now produce 64 kg of plutonium per year. [36]

Pakistan is a member of some multilateral programs, including the Global Initiative to Combat Nuclear Terrorism (GICNT). Pakistan is not a signatory to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), and is the sole country blocking negotiations of the Fissile Material Cut-Off Treaty (FMCT). Pakistan argues that in the face of India's increasing conventional capability, it is unreasonable to expect Pakistan to cap its fissile materials production. While declaring its opposition to the FMCT in its current format at the Conference on Disarmament (CD) in January 2010, Pakistan called for the CD's agenda to be enlarged to consider aspects of regional conventional arms control and a regime on missile-related issues, while also maintaining its opposition to a treaty that did not cover fissile stocks retroactively. [37] Pakistan has also consistently refused to sign the Comprehensive Nuclear Test Ban Treaty (CTBT).

In general, Pakistan's position on nuclear disarmament is that it will only give up nuclear weapons if India gives up its own nuclear arsenal. However, given Pakistan’s objective of balancing India's conventional military and nuclear superiority, Pakistan is unlikely to consent to a denuclearization agreement. [38] From 2009 to 2010 official Pakistani statements indicated that even if India signed the CTBT, Pakistan would not necessarily follow suit. [39]

At the Nuclear Security Summit in Washington, DC in April 2010, Pakistan again sought "non-discriminatory access" to civilian nuclear technology, while also offering nuclear fuel cycle services covered by IAEA safeguards to the international community. [40]

Recent Developments & Current Status

In October 2015, Pakistan declared that it had developed tactical nuclear weapons. The Pakistani government has clarified that these would be used only in the event of a conflict with India. However, even though Pakistan had been suspected of building tactical nuclear weapons for many years, the official announcement has caused concern within the international community, especially in the United States. The weapons’ small size and yield have ignited concern over their possible destabilizing effects in a potential conflict with India. [41] Because of India's conventional military superiority, Pakistan maintains the ability to quickly escalate to the use of nuclear weapons in case of a conventional Indian military attack. [42]

On 24 March 2016, Pakistan announced that it has ratified the Amendment to the Convention on the Physical Protection of Nuclear Material (CPPNM). The amendment entered into force on 8 May 2016 after the requisite number of states ratified the amendment. [43] In December 2016 Pakistan issued an updated control list including nuclear and missile-related dual-use goods to bring its restrictions in line with those of the Nuclear Suppliers Group (NSG), the Missile Technology Control Regime (MTCR), and the Australia Group (AG).

The Chinese-built PWRs at Chashma, CHASNUPP-3 and CHASNUPP-4 were inaugurated in 2016 and 2017 respectively. [44] In November 2017, Pakistan signed a deal with China to build an additional 1100-MW PWR at Chashma, to be called CHASNUPP-5. [45]

Sources:
[1] Hans M. Kristensen and Robert S. Norris, "Pakistan's Nuclear Forces, 2011," Bulletin of the Atomic Scientists, 67(4), 2011.
[2] SIPRI Yearbook 2019 (Stockholm: Stockholm International Peace Research Institute, 2019).
[3] "Pakistan," International Panel on Fissile Materials, www.fissilematerials.org.
[4] Mark Hibbs, "Pakistan Developed More Powerful Centrifuges," Nuclear Fuel, 29 January 2007, p. 1, pp. 15-16; Jeffrey Lewis, "P3 and P4 Centrifuge Data," Arms Control Wonk, 15 February 2007, http://armscontrolwonk.com; David Albright and Serena Kelleher-Vergantini, "Pakistan’s Fourth Reactor at Khushab Now Appears Operational," Institute for Science and International Security, 6 January 2015, http://isis-online.org.
[5] "History of PAEC," Pakistan Atomic Energy Commission, 13 December 2011, www.paec.gov.pk/paec-hist.htm.
[6] Feroz Hassan Khan, Eating Grass: The Making of the Pakistani Bomb (Stanford, CA: Stanford University Press, 2012).
[7] George Perkovich, "Could Anything Be Done to Stop Them? Lessons from Pakistan's Proliferating Past," in Pakistan's Nuclear Future: Worries Beyond War, Henry D. Sokolski, ed., (Carlisle, PA: Strategic Studies Institute, 2008).
[8] Nuclear Black Markets: Pakistan, A.Q. Khan and the Rise of Proliferation Networks, (International Institute for Strategic Studies: London, 2007).
[9] Feroz Hassan Khan, Eating Grass: The Making of the Pakistani Bomb (Stanford, CA: Stanford University Press, 2012), p. 100.
[10] Nuclear Black Markets: Pakistan, A.Q. Khan and the Rise of Proliferation Networks, (International Institute for Strategic Studies: London, 2007).
[11] Bruno Tertrais, "Not a 'Wal-Mart', but an 'Imports-Exports Enterprise': Understanding the Nature of the A.Q. Khan Network," Strategic Insights, Vol. VI, Issue 5, August 2007.
[12] "Interview with Abdul Qadeer Khan," The News (Islamabad), 30 May 1998, http://nuclearweaponarchive.org.
[13] T.V. Paul, "Chinese-Pakistani Nuclear/Missile Ties and the Balance of Power," The Nonproliferation Review, Summer 2003.
[14] Nuclear Black Markets: Pakistan, A.Q. Khan and the Rise of Proliferation Networks, (London: International Institute for Strategic Studies, 2007).
[15] Bruno Tertrais, "Kahn's Nuclear Exports: Was There a State Strategy?" in Pakistan's Nuclear Future: Worries Beyond War, Henry D. Sokolski, ed., (Carlisle, PA: Strategic Studies Institute, 2008).
[16] Rai Muhammad Saleh Azam, "When Mountains Move – The Story of Chagai," The Nation, www.defencejournal.com.
[17] Scott D. Sagan, "The Evolution of Pakistani and Indian Nuclear Doctrine," in Inside Nuclear South Asia, Scott D. Sagan, ed., (Stanford: Stanford University Press, 2009), pp. 219-220.
[18] Tamara Patton, "Combining Satellite Imagery and 3D Drawing Tools for Nonproliferation Analysis: A Case Study of Pakistan's Khushab Plutonium Production Reactors," Science & Global Security, 20:2-3, p. 137.
[19] Peter R. Lavoy, "Islamabad's Nuclear Posture: Its Premises and Implementation," in Pakistan's Nuclear Future: Worries Beyond War, Henry D. Sokolski, ed., (Carlisle, PA: Strategic Studies Institute, 2008).
[20] Feroz Hassan Khan, Eating Grass: The Making of the Pakistani Bomb (Stanford, CA: Stanford University Press, 2012), pp. 351-352.
[21] Declan Walsh, "Militants Attack Pakistani Air Force Base," The New York Times, 16 August 2012, www.nytimes.com.
[22] Shaiq Hussain, "Militants Storm Pakistan Air Base; 10 Killed," The Washington Post, 15 August 2012, www.washingtonpost.com.
[23] Michelle Marchesano, "Meeting the Nuclear Security Challenge in Pakistan," Partnership for Global Security, Conference Report, April 2008, www.partnershipforglobalsecurity.org.
[24] Paul K. Kerr and Mary Beth Nikitin, "Pakistan's Nuclear Weapons: Proliferation and Security Issues," Congressional Research Service Report RL 34248, 30 November 2011, www.fas.org.
[25] "NA Passes National Command Authority Bill 2009," The Daily Times, 29 January 2010, www.dailytimes.com.
[26] Baqir Sajjad Syed, "Expectations for civilian nuclear deal dampened by US," Dawn, 9 April 2010, www.dawn.com.
[27] "UN Endorses India-US Nuclear Pact," The Australian, 4 August 2008, www.theaustralian.news.com.au.
[28] "Nuclear Power in Pakistan," World Nuclear Association, updated August 2011, www.world-nuclear.org.
[29] “Assessing Progress on Nuclear Nonproliferation and Disarmament,” Arms Control Association, July 2016, www.armscontrol.org.
[30] “Atom body should address China-Pakistan deal -- U.S” Reuters, 22 September 2010, www.reuters.com.
[31] “China says its nuclear cooperation with Pakistan under NSG norms,” The Indian Express, 4 August 2016, www.indianexpress.com.
[32] Peter Wonacott, "Inside Pakistan's Drive to Guard Its A-Bombs," The Wall Street Journal, 29 November 2007, http://online.wsj.com.
[33] David Albright and Robert Avagyan, "Construction Progressing Rapidly on the Fourth Heavy Water Reactor at the Khushab Nuclear Site," Institute for Science and International Security, 21 May 2012, http://isis-online.org.
[34] Sharad Joshi and Togzhan Kassenova, "Pakistan and Cooperative Threat Reduction," Nuclear Threat Initiative, Issue Brief, 4 August 2008, www.nti.org.
[35] Tamara Patton, "Combining Satellite Imagery and 3D Drawing Tools for Nonproliferation Analysis: A Case Study of Pakistan's Khushab Plutonium Production Reactors," Science & Global Security, 20:2-3, p. 137.
[36] This estimate will vary depending on operating time of each reactor. Tamara Patton, "Combining Satellite Imagery and 3D Drawing Tools for Nonproliferation Analysis: A Case Study of Pakistan's Khushab Plutonium Production Reactors," Science & Global Security, 20:2-3, p. 137.
[37] "Pakistan Blocks Agenda at UN Disarmament Conference," The Daily Times, 20 January 2010, www.dawn.com; "Pakistan Rejects Atom Bomb Material Cut-Off Talks, Cites Danger From India," Reuters, 25 January 2010, www.reuters.com.
[38] "Country Perspectives on the Challenges to Nuclear Disarmament," International Panel on Fissile Materials, 2010, www.fissilematerials.org.
[39] "Pakistan Rules Out Test Ban Treaty Endorsement," Global Security Newswire, 19 June 2009, www.globalsecuritynewswire.org; "No Proposal to Sign Nuclear Ban Treaty," Global Security Newswire, 1 January 2010, www.globalsecuritynewswire.org.
[40] "Pakistan Seeks Equal Access to Civil Nuclear Technology," Dawn, 12 April 2010, www.dawn.com; Louis Charbonneau, "Pakistan Offers Global Nuclear Fuel Services Again," Reuters, 13 April 2010, www.reuters.com.
[41] Mohammad Ilyas Khan, “Why Pakistan Is Opening Up Over Its Nuclear Program,” BBC, 21 October 2015, www.bbc.com.
[42] Vipin Narang, "Posturing for Peace?" International Security, Vol. 34, No. 3, Winter 2009/10.
[43] “Pakistan Deposits Instrument of Ratification of Amendment to Convention on Physical Protection of Nuclear Material in Vienna,” Ministry of Foreign Affairs – Government of Pakistan, 24 March 2016, www.mofa.gov.pk.
[44] Mark Hibbs, "Pakistan Deal Signals China's Growing Nuclear Assertiveness," Nuclear Energy Brief, 27 April 2010, Carnegie Endowment for International Peace, www.carnegieendowment.org.
[45] “China signs deal to build new nuclear reactor in Pakistan: WNN,” Reuters, 24 November 2017, www.reuters.com.