The prohibition on development, production, manufacturing, and other acquisition
Nine states not party to the TPNW – the nuclear- armed states China, France, India, Israel, North Korea, Pakistan, Russia, United Kingdom, and the United States – engaged in conduct in 2021 that was not compatible with the Treaty’s prohibition on developing, producing, manufacturing, or otherwise acquiring nuclear weapons. Two further states not party – Iran and Saudi Arabia – were recorded as states of concern.


Most nuclear-armed states brand their ongoing development and production efforts as ‘modernization’, but all continue to be actively engaged in development and production of new nuclear delivery vehicles and/ or warheads, upgrading and perpetuating their nuclear capabilities. An overview of each nuclear-armed state’s new nuclear-weapon systems under development, production, or acquisition in 2021 can be found in their respective state profiles on this website.
Many weapon systems currently being developed and produced are set to remain operational into the 2070s and 2080s, implying that the states in question are committing themselves to nuclear armament for at least half a century into the future – longer than the NPT has been in existence. This qualitative and quantitative vertical proliferation is now framed as a new and unexpected nuclear arms race, rather than a systemic feature of living in a nuclear-armed world in which states compete to sustain their own nuclear capabilities and deterrence doctrines whilst challenging and attempting to negate those of their adversaries. Many nuclear-armed states are also reinvigorating or even expanding the role of nuclear weapons in their military doctrines. It is particularly worrisome that several nuclear-armed states are now increasingly posturing themselves for nuclear warfighting. It is also important to note that the arms race is directly fuelled by the tremendous influence that weapons contractors, lobbyists, and financial institutions have on governmental nuclear policy decisions.
Each State Party undertakes never under any circumstances to: ‘Develop, […] produce, manufacture, otherwise acquire […] nuclear weapons or other nuclear explosive devices.’
• The prohibited ‘development’ of a nuclear weapon or other nuclear explosive device encompasses any of the actions and activities intended to prepare for its production. This covers relevant research, computer modelling of weapons, and the testing of key components, as well as sub-critical testing (i.e. experiments simulating aspects of nuclear explosions using conventional explosives and without achieving uncontrolled nuclear chain reactions).
• The concepts of ‘production’ and ‘manufacture’ overlap significantly, covering the processes that are intended to lead to a completed, useable weapon or device. In general parlance, ‘production’ is a broader term than ‘manufacture’: manufacture describes the use of machinery to transform inputs into outputs. Taken together, these concepts encompass not only any factory processes, but also any improvisation or adaptation of a nuclear explosive device.
• The prohibition on ‘otherwise acquiring’ a nuclear weapon or other nuclear explosive device is a catch-all provision that encompasses any means of obtaining nuclear weapons or other nuclear explosive devices other than through production. This could be through import, lease, or borrowing from another source or, in theory, by recovering a lost nuclear weapon or capturing or stealing one. This prohibition overlaps with the one in Article 1(1)(c) not to receive the control over nuclear weapons or other nuclear explosive devices (discussed below).
• The prohibition on development, production, manufacturing, and acquisition also cover key components. It is widely accepted that the missile, rocket, or other munition, including both the container and any means of propulsion, are key components in a nuclear weapon. Delivery platforms such as bombers and submarines are not key components of nuclear weapons as such, and are not captured by the prohibitions in Article 1, though they may be integral to a nuclear-weapon system.
• Key components are of course also the fissile material (plutonium or highly enriched uranium) and the means of triggering the nuclear chain reaction. Production or procurement of fissile material constitutes prohibited development when this is done with the intent to produce nuclear weapons or other nuclear explosive devices. To research, produce, and use nuclear energy for peaceful purposes is permitted both under the NPT and the TPNW.
• Development and production of dual-use components, such as navigation or guidance systems, which could be used in both nuclear and conventional weapons, would only be prohibited under the TPNW when they were intended to be used in nuclear weapons.
• Under Article II of the NPT, a similar obligation is imposed not to manufacture or otherwise acquire nuclear weapons or other nuclear explosive devices, but this applies only to the non-nuclear-weapon states designated under the Treaty and does not prohibit nuclear-weapon states from continuing to develop, produce, and manufacture nuclear weapons or other nuclear explosive devices.
• As is the case with the NPT, the TPNW does not define ‘nuclear weapons’ or ‘other nuclear explosive devices’. There is, though, a settled understanding among states of these terms.
• A nuclear explosive device is an explosive device whose effects are derived primarily from nuclear chain reactions.
• A nuclear weapon is a nuclear explosive device that has been weaponized, meaning that it is contained in and delivered by, for example, a missile, rocket, or bomb.
• Thus, all nuclear weapons are a form of nuclear explosive device but not all nuclear explosive devices are nuclear weapons.
States of concern
The Nuclear Weapons Ban Monitor continues to list Iran and Saudi Arabia as states of concern in relation to the prohibition on developing, producing, manufacturing, or otherwise acquiring nuclear weapons. They do not possess nuclear weapons, but both have latent nuclear breakout capabilities. Therefore, in the event that either state intended to become party to the TPNW, possible compliance issues would need to be addressed by a meeting of states parties or review conference.
Following the US withdrawal from the Joint Comprehensive Plan of Action (JCPOA), Iran restarted uranium enrichment beyond levels previously permitted by the agreement; as of November 2021, it was estimated that Iran had a stockpile of 113.8 kg of uranium enriched up to 20%, and 17.7 kg of uranium enriched up to 60%. This is particularly worrisome, because very little additional work is required to enrich uranium from 20 per cent to weapons-grade status. These developments have therefore effectively reduced Iran’s potential nuclear breakout time from approximately a year under the JCPOA to just a couple of months, although there is currently little public indication that Tehran intends to take that highly consequential step at this time. It is concerning, however, that since February 2021 Iran has continuously refused to allow the IAEA access to a facility where advanced centrifuge components are being produced; this could complicate a potential return to compliance with the JCPOA. At the time of writing, the United States and the remaining parties to the JCPOA were in the midst of negotiations over a potential US return to the deal (or perhaps the conclusion of a new interim deal); however, it remained to be seen whether either option would be possible in 2022.
If Iran obtained a true nuclear capability, Saudi Arabia would almost certainly follow through on its promise to acquire one as well. Although Saudi Arabia’s capabilities are much further behind Iran’s, the country possesses a sizable stockpile of mineable uranium ore; has announced an intention to build several nuclear reactors across the country; and possesses several types of ballistic missiles that could be used to deliver nuclear warheads. While these factors do not necessarily indicate the country’s interest in developing nuclear weapons at this time, Saudi Arabia’s Small Quantities Protocol exempts the country from IAEA monitoring and inspections obligations, which increases ambiguity around the country’s nuclear intentions and capabilities.
Missile tests
Test launches of missiles that are either specifically designed to deliver nuclear warheads or which are ‘nuclear-capable’ are often used to validate particular delivery systems or subcomponents and therefore constitute prohibited development of nuclear weapons under Article 1(1)(a) of the TPNW (unless the purpose of the launch is to test the conventional capability of the missile). Information from public reports, which may not be exhaustive, shows that seven of the nine nuclear-armed states (China, France, India, North Korea, Pakistan, Russia, and the United States) tested nuclear missiles in 2021.
For more information, see, in particular, the news section of the Missile Threat website produced by CSIS.
Fissile Material
Fissile material — plutonium or highly enriched uranium (HEU)55 — is essential for all nuclear weapons. Both military and civilian stocks of HEU and plutonium must be secured and reduced (and further production limited) in order to achieve nuclear disarmament, halt proliferation of nuclear weapons, and ensure that terrorists do not acquire them. Production or procurement of fissile material constitutes prohibited development under the TPNW when done with the intent to produce nuclear weapons or other nuclear explosive devices.
According to the International Panel on Fissile Materials (IPFM), the global stockpile of HEU was estimated to be about 1,330 metric tonnes at the beginning of 2020, while the global stockpile of separated plutonium was about 540 tonnes, of which about 316 tonnes was civilian plutonium. Russia and the United States possess enormous quantities of both HEU and plutonium that could be used to produce tens of thousands of new nuclear weapons. Enriched uranium is also used in civilian reactor fuel. As of May 2021, 13 non-nuclear-armed states (Australia, Belarus, Belgium, Canada, Germany, Iran, Italy, Japan, Kazakhstan, Netherlands, Norway, South Africa, and Syria) had at least 1kg of HEU in civilian stockpiles, and some of them between 1 and 10 tonnes. One of these – Japan – also has a very large stockpile of 45.5 tonnes of separated plutonium, some in storage in the United Kingdom and in France, and some on its territory, theoretically sufficient for the production of thousands of nuclear weapons. However, there is currently no indication that any of these countries intends to develop a military nuclear-weapons programme.
Facilities that can produce fissile material (reprocessing plants and/or enrichment facilities) exist in 15 states (the nine nuclear-armed states plus Argentina, Brazil, Germany, Iran, Japan, and the Netherlands). Of these, production of fissile material intended for nuclear weapons appears to continue in India, Israel, North Korea, and Pakistan. China, Russia, and the United States do not currently appear to be producing new fissile material for weapons, but continue to operate at least one reprocessing plant or enrichment facility without non-proliferation safeguards attached. The remaining two nuclear-armed states, France and the United Kingdom now only possess fissile material production complexes under safeguards, as do Argentina, Brazil, Germany, Iran, Japan, and the Netherlands.
Under international law, mining and transfer of uranium is generally lawful, unless it is being done for the purpose of developing or assisting in the development of a nuclear explosive device. The peaceful use of nuclear energy is protected under Article IV of the NPT (and customary international law), and the Preamble to the TPNW confirms that nothing in the Treaty should be interpreted as affecting that right. A state may therefore extract uranium and
either use the nuclear material itself or provide it to another state for peaceful purposes, as long as it is subject to Safeguards Agreements with the IAEA.
Under the TPNW, the provision of uranium to any other state is prohibited where it is not subject to appropriate Safeguards Agreements or if the state party transferring the uranium knows that the material in question will, or is likely to, be used to develop a nuclear weapon or other nuclear explosive device. Otherwise, states parties to the TPNW are permitted to transfer uranium, including to nuclear-armed states and states not party to the TPNW. Several states that mine and export uranium are party to the TPNW, including Kazakhstan, Namibia, and South Africa.
Under the NPT, the provision of uranium to any non-nuclear-weapon state is unlawful where it is not subject to appropriate Safeguards Agreements. The NPT does not directly address the legality of provision of uranium to the five nuclear-weapon states designated under that Treaty.
If a state exports uranium to a nuclear-armed state or any other state subject to IAEA safeguards and on the understanding that the uranium would be used exclusively for peaceful purposes, the exporting state could not be considered to be in violation of either the TPNW or the NPT if the importing state unexpectedly decided to use the uranium for weapons development instead. This would, though, affect the legality of any future exports of uranium to that state.
When armed groups control areas of a state’s territory, or when an armed conflict is ongoing, situations could occur where it would be difficult for the authorities of a state in which uranium deposits exist to effectively control all extraction and transfers. If a non-state actor in such a situation were to transfer uranium to an actor intending to develop a nuclear explosive device, the territorial state could not be considered to be in violation either of the TPNW or the NPT, provided that it has made all reasonable efforts to prevent such extraction and transfers. All reasonable efforts would include the adoption of national legislation and implementation of other practical measures to secure as far as possible sites in which uranium is present or where stocks of uranium are held.