Instruct: Given a question, retrieve relevant passages that can help answer the question.
Query: When was the first nuclear weapon created?
In January 1933, Adolf Hitler was appointed Chancellor of Germany and it quickly became unsafe for Jewish scientists to remain in the country. Leó Szilárd fled to London where he proposed, and in 1934 patented, the idea of a nuclear chain reaction via neutrons. The patent also introduced the term critical mass to describe the minimum amount of material required to sustain the chain reaction and its potential to cause an explosion. (British patent 630,726.) He subsequently assigned the patent to the British Admiralty so that it could be covered by the Official Secrets Act.[2] In a very real sense, Szilárd was the father of the atomic bomb academically. Also in 1934, Irène and Frédéric Joliot-Curie discovered that artificial radioactivity could be induced in stable elements by bombarding them with alpha particles; Enrico Fermi reported similar results when bombarding uranium with neutrons.
According to a 2013 report by the "Bulletin of the Atomic Scientists", which cited US Defense Intelligence Agency figures, Israel began the production of nuclear weapons in 1967, when it produced its first two nuclear bombs. According to the report's calculations, Israel produced nuclear weapons at an average rate of two per year, and stopped production in 2004. The report stated that Israel has 80 nuclear warheads and has enough fissile material to produce 190 more. In 2014, former US president Jimmy Carter stated that "Israel has, what, 300 or more, nobody knows exactly how many" nuclear weapons.
The United States is known to have possessed three types of weapons of mass destruction: nuclear weapons, chemical weapons, and biological weapons. The U.S. is the only country to have used nuclear weapons in combat, when it detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki during World War II. It had secretly developed the earliest form of the atomic weapon during the 1940s under the title "Manhattan Project". The United States pioneered the development of both the nuclear fission and hydrogen bombs (the latter involving nuclear fusion). It was the world's first and only nuclear power for four years (1945–1949), until the Soviet Union managed to produce its own nuclear weapon. The United States has the second largest number of deployed nuclear weapons in the world, after Russia.
The State of Israel is widely believed to possess nuclear weapons. Current estimates put the size of the Israeli nuclear arsenal at between 80 and 400 nuclear warheads, and the country is believed to possess the ability to deliver them in a variety of methods including: aircraft; submarine-launched cruise missiles; and the Jericho series of intermediate to intercontinental range ballistic missiles. Its first deliverable nuclear weapon is thought to have been created in late 1966 or early 1967; which would make it the sixth country in the world to have developed them.
In the wake of the full-scale tests and signing of the test ban treaty, the Air Force Weapons Laboratory (AFWL) was created from elements of the Special Weapons Center. The AFWL was responsible for researching nuclear weapons and the vulnerability of U.S. weapons systems to nuclear attack. Because atmospheric testing had been prohibited in 1963, weapons vulnerability testing now focused on nuclear weapons effects simulations. AFWL's original mission was to explore the military uses of nuclear power, weapons, and
support equipment, and to reduce the vulnerability of U.S. systems to nuclear weapons effects. This involved studying nuclear weapons effects through testing, ensuring the compatibility of nuclear weapons with USAF delivery systems, providing advanced nuclear weapons delivery techniques, and investigating nuclear power concepts.
The UK has not declared a no first use policy regarding launching a nuclear attack; former British defence secretary Geoff Hoon stated in 2002 and 2003 that the UK would be willing to attack rogue states with them if nuclear weapons were used against British troops. In April 2017 Defence Secretary Michael Fallon confirmed that the UK would use nuclear weapons in a "pre-emptive initial strike" in "the most extreme circumstances". Fallon stated in a parliamentary answer that the UK has neither a 'first use' or 'no first use' in its nuclear weapon policy so that its adversaries would not know when the UK would launch nuclear strikes. 
National leaders debated the impact of nuclear weapons on domestic and foreign policy. Also involved in the debate about nuclear weapons policy was the scientific community, through professional associations such as the Federation of Atomic Scientists and the Pugwash Conference on Science and World Affairs.[34] Radioactive fallout from nuclear weapons testing was first drawn to public attention in 1954 when a Hydrogen bomb test in the Pacific contaminated the crew of the Japanese fishing boat Lucky Dragon.[35] One of the fishermen died in Japan seven months later. The incident caused widespread concern around the world and "provided a decisive impetus for the emergence of the anti-nuclear weapons movement in many countries".[35] The anti-nuclear weapons movement grew rapidly because for many people the atomic bomb "encapsulated the very worst direction in which society was moving".[36]
Of the nuclear powers, only the People's Republic of China and India have declarative, unqualified, unconditional no-first-use policies. In 1982, at a special session of the General Assembly of United Nations, the USSR pledged not to use nuclear weapons first, regardless of whether its opponents possessed nuclear weapons or not. This pledge was later abandoned by post-Soviet Russia to compensate the overwhelming conventional weapon superiority enjoyed by NATO. The United States has a partial, qualified no-first-use policy, stating that they will not use nuclear weapons against states that do not possess nuclear weapons or other weapons of mass destruction.
Since the Trinity test and excluding the combat use of nuclear weapons, mankind (those few nations with capability) has detonated roughly 1,700 nuclear explosions, all but 6 as tests. Of these, six were peaceful nuclear explosions. Nuclear tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the 20th century, most nations that have developed nuclear weapons had a staged test of them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how structures behave when subjected to a nuclear explosion. Additionally, nuclear testing has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.
The nuclear weapons debate refers to the controversies surrounding the threat, use and stockpiling of nuclear weapons. Even before the first nuclear weapons had been developed, scientists involved with the Manhattan Project were divided over the use of the weapon. The only time nuclear weapons have been used in warfare was during the final stages of World War II when United States Army Air Forces B-29 Superfortress bombers dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki in early August 1945. The role of the bombings in Japan's surrender and the U.S.'s ethical justification for them have been the subject of scholarly and popular debate for decades.
Nuclear disarmament refers both to the act of reducing or eliminating nuclear weapons and to the end state of a nuclear-free world. Proponents of disarmament typically condemn a priori the threat or use of nuclear weapons as immoral and argue that only total disarmament can eliminate the possibility of nuclear war. Critics of nuclear disarmament say that it would undermine deterrence and make conventional wars more likely, more destructive, or both. The debate becomes considerably complex when considering various scenarios for example, total vs partial or unilateral vs multilateral disarmament.
The United Kingdom became a nuclear power in 1952, and their nuclear arsenal peaked at just under 500 nuclear weapons in 1981. France became a nuclear power in 1960, and French nuclear stockpiles peaked at just over 500 nuclear weapons in 1992. China developed its first nuclear weapon in 1964; its nuclear stockpile increased until the early 1980s, when it stabilized at between 200 and 260. India became a nuclear power in 1974, while Pakistan developed its first nuclear weapon in the 1980s. India and Pakistan currently have around one hundred nuclear weapons each. Pakistan's nuclear stockpile has increased rapidly, and it is speculated that Pakistan might have more nuclear weapons than the United Kingdom within a decade.
Enrichment technology is primarily used to create enriched nuclear fuel, but it can also be used to create weapons-grade nuclear material. The main goal of a fuel bank is therefore to minimize the risk of further nuclear weapons proliferation by removing the need for countries to possess enrichment technology.
A U.S. policy to "neither confirm nor deny" the presence of nuclear weapons was created during the late 1950s when Japan's government asked for a guarantee that U.S. nuclear weapons would not be based "in Japan."
The United States has refused to adopt a no-first-use policy, saying that it "reserves the right to use" nuclear weapons first in the case of conflict. The U.S. doctrine for the use of nuclear weapons was revised most recently in the Nuclear Posture Review, released April 6, 2010. The 2010 Nuclear Posture review reduces the role of U.S. nuclear weapons, stating that, "The fundamental role of U.S. nuclear weapons, which will continue as long as nuclear weapons exist, is to deter nuclear attack on the United States, our allies, and partners." The U.S. doctrine also includes the following assurance to other states: "The United States will not use or threaten to use nuclear weapons against non-nuclear weapons states that are party to the NPT and in compliance with their nuclear non-proliferation obligations."
Research has been done into the possibility of pure fusion bombs: nuclear weapons that consist of fusion reactions without requiring a fission bomb to initiate them. Such a device might provide a simpler path to thermonuclear weapons than one that required development of fission weapons first, and pure fusion weapons would create significantly less nuclear fallout than other thermonuclear weapons, because they would not disperse fission products. In 1998, the United States Department of Energy divulged that the United States had, "...made a substantial investment" in the past to develop pure fusion weapons, but that, "The U.S. does not have and is not developing a pure fusion weapon", and that, "No credible design for a pure fusion weapon resulted from the DOE investment".[18]
Proliferation begets proliferation is a concept described by Scott Sagan in his article, "Why Do States Build Nuclear Weapons?". This concept can be described as a strategic chain reaction. If one state produces a nuclear weapon it creates almost a domino effect within the region. States in the region will seek to acquire nuclear weapons to balance or eliminate the security threat. Sagan describes this reaction best in his article when he states, “Every time one state develops nuclear weapons to balance against its main rival, it also creates a nuclear threat to another region, which then has to initiate its own nuclear weapons program to maintain its national security”. Going back through history we can see how this has taken place. When the United States demonstrated that it had nuclear power capabilities after the bombing of Hiroshima and Nagasaki, the Russians started to develop their program in preparation for the Cold War. With the Russian military buildup, France and the United Kingdom perceived this as a security threat and therefore they pursued nuclear weapons (Sagan, pg 71). Even though proliferation causes proliferation, this does not guarantee that other states will successfully develop nuclear weapons because the economic stability of a state plays an important role on whether the state will successfully be able to acquire nuclear weapons. The article written by Dong-Jong Joo and Erik Gartzke discusses how the economy of a country determines whether they will successfully acquire nuclear weapons.
Weapon systems engineering involves using engineering tools in technology to create and guarantee the safety and performance of weapons. It is currently being used by the military and the government to create new weapons to protect the United States. It is used to make nuclear and non-nuclear weapons and ensure their safety throughout their lifespan. 
In the wake of the signing of the Partial Nuclear Test Ban Treaty in 1963, the Air Force Weapons Laboratory (AFWL) was created from the Research Directorate elements of the Special Weapons Center. The Special Weapons Center gave up much of its research and development work to the newly created Air Force Weapons Laboratory. The Center continued with its test and evaluation mission and as Kirtland's host organization. The Weapons Laboratory built facilities during the 1960s to simulate nuclear effects such as transient radiation, X-rays, and electromagnetic pulse (EMP).
Research into the development of nuclear weapons was initially undertaken during World War II by the United States (in cooperation with the United Kingdom and Canada), Germany, Japan, and the USSR. 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 to end the war, Germany and Japan ceased to be involved in any nuclear weapon research. In August 1949, the USSR tested a nuclear weapon, becoming the second country to detonate a nuclear bomb. The United Kingdom first tested a nuclear weapon in October 1952. France first tested a nuclear weapon in 1960. The People's Republic of China detonated a nuclear weapon in 1964. India conducted its first nuclear test in 1974, which prompted Pakistan to develop its own nuclear program and, when India conducted a second series of nuclear tests in 1998, Pakistan followed with a series of tests of its own. In 2006, North Korea conducted its first nuclear test.
This break from the linear expectation of more fire damage to occur after greater explosive yield is dropped can be easily explained by two major factors. First, the order of blast and thermal events during a nuclear explosion is not ideal for the creation of fires. In an incendiary bombing raid, incendiary weapons followed after high-explosive blast weapons were dropped, in a manner designed to create the greatest probability of fires from a limited quantity of explosive and incendiary weapons. The so-called two-ton "cookies", also known as "blockbusters", were dropped first and were intended to rupture water mains, as well as to blow off roofs, doors, and windows, creating an air flow that would feed the fires caused by the incendiaries that would then follow and be dropped, ideally, into holes created by the prior blast weapons, such into attic and roof spaces. On the other hand, nuclear weapons produce effects that are in the reverse order, with thermal effects and "flash" occurring first, which are then followed by the slower blast wave. It is for this reason that conventional incendiary bombing raids are considered to be a great deal more efficient at causing mass fires than nuclear weapons of comparable yield. It is likely this led the nuclear weapon effects experts Franklin D'Olier, Samuel Glasstone and Philip J. Dolan to state that the same fire damage suffered at Hiroshima could have instead been produced by about 1 kiloton/1,000 tons of incendiary bombs.
The first nuclear weapon was created by the United States of America. During the Second World War and was developed to be used against the Axis powers. Scientists of the Soviet Union were aware of the potential of nuclear weapons and had also been conducting research on the field.
Comprehensive Nuclear-Test-Ban Treaty Doomsday Clock Historical nuclear weapons stockpiles and nuclear tests by country Nuclear disarmament Nuclear latency Nuclear proliferation Nuclear war Nuclear terrorism Nuclear-weapon-free zone Nuclear power No first use International Campaign to Abolish Nuclear Weapons
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield, and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that developed nuclear weapons tested them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how personnel, structures, and equipment behave when subjected to nuclear explosions. Nuclear testing has often been used as an indicator of scientific and military strength, and many tests have been overtly political in their intention; most nuclear weapons states publicly declared their nuclear status by means of a nuclear test.
The novel then goes back in time to 1898, when the Marie Curie and her husband discover radioactivity. The story presents a brief timeline that continues up into the 1930s, when James Chadwick discovers neutrons and the discovery of nuclear fission. The novel takes a shift, and begins to discuss the political environment. Leo Szilard becomes troubled as he sees the dangers that these nuclear weapons could produce, and travels with Eugene Wigner to talk with Albert Einstein about the possibility of Nazi scientists creating a bomb. News soon reaches the United States president, who authorizes the precursor to the Manhattan Project. After the bombing of Pearl Harbor, the United States founds covertly Los Alamos National Laboratory and other cities to create nuclear weapons. The scientists and their families are sworn to secrecy. Soon, the scientists at Los Alamos discover how to create a nuclear chain reaction, leading to the development of the first atomic weapons: Little Boy and Fat Man.
In 1999, the Kargil War between India and Pakistan became the first direct conflict between two declared nuclear powers. As the war progressed, the first hint of the possible use of a nuclear weapon was on 31 May, when Pakistani foreign secretary Shamshad Ahmad made a statement warning that an escalation of the limited conflict could lead Pakistan to use "any weapon" in its arsenal. This was immediately interpreted as an obvious threat of a nuclear retaliation by Pakistan in the event of an extended war. The leader of Pakistan's senate noted that "the purpose of developing weapons becomes meaningless if they are not used when they are needed." Some experts believe that following nuclear tests in 1998, Pakistani military was emboldened by its nuclear deterrent cover to markedly increase coercion against India.