Editing Nuclear weapon design (section)

{{Short description|Process by which nuclear WMDs are designed and produced}}
[[File:The gadget in the Trinity Test Site tower (1945).jpg|right|thumb|300px|The first nuclear explosive devices provided the basic building blocks of future weapons. Pictured is the ''Gadget'' device being prepared for the [[Trinity (nuclear test)|Trinity nuclear test]].]]

'''Nuclear weapons design''' are physical, chemical, and engineering arrangements that cause the physics package<ref>The physics package is the nuclear explosive module inside the bomb casing, missile warhead, or artillery shell, etc., which delivers the weapon to its target. While photographs of weapon casings are common, photographs of the physics package are quite rare, even for the oldest and crudest nuclear weapons. For a photograph of a modern physics package see [[W80 (nuclear warhead)|W80]].</ref> of a [[nuclear weapon]] to detonate. There are three existing basic design types:
# '''Pure fission weapons''' are the simplest, least technically demanding, were the first nuclear weapons built, and so far the only type ever used in warfare, by the United States on [[Empire of Japan|Japan]] in [[World War II]].
# '''[[Boosted fission weapon]]s''' increase yield beyond that of the implosion design, by using small quantities of fusion fuel to enhance the fission chain reaction. Boosting can more than double the weapon's fission energy yield.
# '''Staged [[thermonuclear weapon]]s''' are arrangements of two or more "stages", most usually two. The first stage is typically a boosted fission weapon (except for the earliest thermonuclear weapons, which used a pure fission weapon). Its detonation causes it to shine intensely with [[X-ray]]s, which illuminate and implode the second stage filled with fusion fuel. This initiates a sequence of events which results in a thermonuclear, or fusion, burn. This process affords potential yields up to hundreds of times those of fission weapons.<ref>{{citation |author= |year=1961 |title=To the Outside World, a Superbomb more Bluff than Bang |magazine=[[Life (magazine)|Life]] |location=New York |volume=51|issue=19, November 10, 1961 |pages=34–37 |url=https://books.google.com/books?id=4VMEAAAAMBAJ&pg=PA34 |access-date=2010-06-28 |url-status=live |archive-url=https://web.archive.org/web/20210904154852/https://books.google.com/books?id=4VMEAAAAMBAJ&pg=PA34 |archive-date=2021-09-04}}. Article on the Soviet [[Tsar Bomba]] test. Because explosions are spherical in shape and targets are spread out on the relatively flat surface of the earth, numerous smaller weapons cause more destruction. From page 35: "...&nbsp;five five-megaton weapons would demolish a greater area than a single 50-megatonner."</ref>

Pure fission weapons have been the first type to be built by new nuclear powers. Large industrial states with well-developed nuclear arsenals have two-stage thermonuclear weapons, which are the most compact, scalable, and cost effective option, once the necessary technical base and industrial infrastructure are built.

Most known innovations in nuclear weapon design originated in the United States, though some were later developed independently by other states.<ref>The United States and the Soviet Union were the only nations to build large nuclear arsenals with every possible type of nuclear weapon. The U.S. had a four-year head start and was the first to produce fissile material and fission weapons, all in 1945. The only Soviet claim for a design first was the [[Joe 4]] detonation on August 12, 1953, said to be the first deliverable hydrogen bomb. However, as Herbert York revealed in ''The Advisors: Oppenheimer, Teller and the Superbomb'' (W.H. Freeman, 1976), it was not a true hydrogen bomb (it was a boosted fission weapon of the Sloika/Alarm Clock type, not a two-stage thermonuclear). Soviet dates for the essential elements of warhead miniaturization – boosted, hollow-pit, two-point, air lens primaries – are not available in the open literature, but the larger size of Soviet ballistic missiles is often explained as evidence of an initial Soviet difficulty in miniaturizing warheads.</ref>

In early news accounts, pure fission weapons were called atomic bombs or '''A-bombs''' and weapons involving fusion were called '''hydrogen bombs''' or '''H-bombs'''. Practitioners of nuclear policy, however, favor the terms nuclear and thermonuclear, respectively.
{{Nuclear weapons}}