Treaty on the Non-Proliferation of Nuclear Weapons in the context of "Nuclear weapons of China"

A thermonuclear weapon, fusion weapon or hydrogen bomb (H-bomb) is a second-generation nuclear weapon, utilizing nuclear fusion. The most destructive weapons ever created, their yields typically exceed first-generation nuclear weapons by twenty times, with far lower mass and volume requirements. Characteristics of fusion reactions can make possible the use of non-fissile depleted uranium as the weapon's main fuel, thus allowing more efficient use of scarce fissile material. Its multi-stage design is distinct from the usage of fusion in simpler boosted fission weapons. The first full-scale thermonuclear test (Ivy Mike) was carried out by the United States in 1952, and the concept has since been employed by at least the five NPT-recognized nuclear-weapon states: the United States, Russia, the United Kingdom, China, and France.

The design of all thermonuclear weapons is believed to be the Teller–Ulam configuration. This relies on radiation implosion, in which X-rays from detonation of the primary stage, a fission bomb, are channelled to compress a separate fusion secondary stage containing thermonuclear fuel, primarily lithium-6 deuteride. During detonation, neutrons convert lithium-6 to helium-4 plus tritium. The heavy isotopes of hydrogen, deuterium and tritium, then undergo a reaction that releases energy and neutrons. For this reason, thermonuclear weapons are often colloquially called hydrogen bombs or H-bombs.

The Strategic Rocket Forces of the Russian Federation (RVSN RF) is a separate combat arm of the Russian Armed Forces that controls Russia's land-based intercontinental ballistic missiles (ICBMs). It was formerly part of the Soviet Armed Forces from 1959 to 1991.

The Strategic Rocket Forces was created on 17 December 1959 as part of the Soviet Armed Forces as the main force for operating all Soviet nuclear ground-based intercontinental, intermediate-range ballistic missile, and medium-range ballistic missile with ranges over 1,000 kilometers. After the Soviet Union collapsed in 1991, assets of the Strategic Rocket Forces were in the territories of several new states in addition to Russia, with armed nuclear missile silos in Belarus, Kazakhstan and Ukraine. On 8 December 1991 according to Belovezha Accords, which dissolved the Soviet Union, the other 3 nuclear member states transferred Soviet missiles on their territory to Russia and they all joined the Nuclear Non-Proliferation Treaty.

Nuclear proliferation is the spread of nuclear weapons to additional countries, particularly those not recognized as nuclear-weapon states by the Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT. Nuclear proliferation occurs through the spread of fissile material, and the technology and capabilities needed to produce it and to design and manufacture nuclear weapons. In a modern context, it also includes the spread of nuclear weapons to non-state actors. Proliferation has been opposed by many nations with and without nuclear weapons, as governments fear that more countries with nuclear weapons will increase the possibility of nuclear warfare (including the so-called countervalue targeting of civilians), de-stabilize international relations, or infringe upon the principle of state sovereignty. Conversely, supporters of deterrence theory argue that controlled proliferation decreases conflict rates via nuclear peace.

Nuclear weapons were initially researched during World War II, jointly by the United States, United Kingdom and Canada, and separately by Germany, Japan, the Soviet Union, and France. The United States was the first and is the only country to have used a nuclear weapon in war, when it used two bombs against Japan in August 1945. After surrendering, Germany and Japan ceased to be involved in any nuclear weapon research. A nuclear arms race followed, with further countries developing and testing nuclear weapons. The US primarily competed with the Soviet Union, which carried out their first test in 1949. Seven other countries developed nuclear weapons during the Cold War. The UK and France, both NATO members, developed fission and fusion weapons throughout the 1950s, and 1960s, respectively. China developed both against the backdrop of the Sino-Soviet split.

The Russian Federation is known to possess or have possessed three types of weapons of mass destruction: nuclear weapons, biological weapons, and chemical weapons. It is one of the five nuclear-weapon states recognized under the Treaty on the Non-Proliferation of Nuclear Weapons and one of the four countries wielding a nuclear triad. Russia has been alleged to violate the Biological Weapons Convention and Chemical Weapons Convention.

As of 2025, Russia's triad of deployed strategic nuclear weapons includes approximately 1,254 intercontinental ballistic missiles, 992 submarine-launched ballistic missiles, and 586 cruise missiles or bombs for delivery by Tupolev Tu-160 and Tu-95 bombers. It also possesses the world's largest arsenal of tactical nuclear weapons, approximately 1,500. Since 2022, Russia has provided tactical nuclear weapons to Belarus.

There are currently nine sovereign states that are generally understood to possess nuclear weapons, though only eight formally acknowledge possessing them. In order of first successful nuclear test, the world's nine nuclear-armed states are the United States (1945), Russia (1949), the United Kingdom (1952), France (1960), China (1964), India (1974), Pakistan (1998), and North Korea (2006); Israel is believed to have acquired nuclear weapons around 1967, but has never openly tested or formally acknowledged having them. Under the Non-Proliferation Treaty (NPT), the United States, Russia, the United Kingdom, France, and China are recognized "nuclear-weapons states" (NWS). They are also the five permanent members of the United Nations Security Council. Israel, India, and Pakistan never signed the NPT, while North Korea acceded to it in 1985 before announcing withdrawal in 2003.

South Africa developed nuclear weapons by 1982 but dismantled them around 1989 and joined the NPT in 1991. Following the dissolution of the Soviet Union in 1991, the former Soviet republics of Ukraine, Kazakhstan, and Belarus had nuclear weapons deployed on their territories, but agreed to transfer them to Russia (which inherited the Soviet Union's international rights and obligations) and join the NPT as non-nuclear-weapon states.

In 1952, the United Kingdom became the third country (after the United States and the Soviet Union) to develop and test nuclear weapons, and is one of the five nuclear-weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons. As of 2025, the UK possesses a stockpile of approximately 225 warheads, with 120 deployed on its only delivery system, the Trident programme's submarine-launched ballistic missiles. Additionally, United States B61 nuclear bombs have been stored at RAF Lakenheath since 2025. In 2025, the UK announced plans to procure 12 F-35A aircraft capable of delivering B61s.

Since 1969, the Royal Navy has operated the continuous at-sea deterrent, with at least one ballistic missile submarine always on patrol. Under the Polaris Sales Agreement, the US supplied the UK with Polaris missiles and nuclear submarine technology, in exchange for the general commitment of these forces to NATO. In 1982, an amendment allowed the purchase of Trident II missiles, and since 1998, Trident has been the only nuclear weapons system in British service. Four Vanguard-class submarines are based at HMNB Clyde in Scotland. Each is armed with up to sixteen Trident II missiles, each carrying warheads in up to eight multiple independently targetable re-entry vehicles (MIRVs).

China was the fifth country to develop and test nuclear weapons. China's tested its first nuclear weapon in 1964 and its first full-scale thermonuclear weapon in 1967. It is one of the five nuclear-weapon states recognized by the Nuclear Non-Proliferation Treaty (NPT), to which it acceded in 1992. It carried out 45 nuclear tests before signing the Comprehensive Nuclear-Test-Ban Treaty in 1996.

The Federation of American Scientists and the Stockholm International Peace Research Institute estimate China's stockpile at approximately 600 nuclear warheads as of 2025, making it the third-largest in the world. It is the only NPT nuclear-weapon state significantly expanding its arsenal, which has doubled since 2019, and is projected to reach between 750 and 1,500 warheads by 2035, although it has not restarted fissile material production. Unlike the US and Russia, nearly all Chinese warheads are believed to be in central storage, separate from their delivery system.