Nuclear fission

Nuclear fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into smaller, lighter nuclei.

Overview
Originally discovered in 1938, nuclear fission was quickly discovered to be a source of large amounts of energy, unleashed both as electromagnetic radiation and as kinetic energy. These principles allowed nuclear fission to be harnessed both as a weapon, starting with the nuclear bombings of Hiroshima and Nagasaki, and as a powerful energy source. Economic pressures culminated in what is best termed a nuclear economy in the United States of the 21st century, when shortages of petroleum and other resources forced the nation to switch to nuclear fission and nuclear fusion as the primary sources of energy. Certain unscrupulous companies, like Mass Fusion, even had the audacity to sell fission products as "fusion," reaping the benefits.

To improve their bottom line, these companies would also demonstrate a wanton disregard for environment, dumping nuclear waste in the wilderness with barely any containment. Nevada and its vast deserts was a popular choice, although the aforementioned Mass Fusion would happily buy up nuclear waste and dump it in remote corners of Massachussetts.

Uses
With petroleum becoming a prohibitively expensive commodity and oil restricted for strategic uses, fission became the primary source of power until the advent of nuclear fusion in 2066. Although expensive and dangerous when used improperly, fission was used widely in a broad variety of applications, including:


 * Nuclear weapons: Fission could produce extremely powerful explosions in a relatively compact package. Fission-based weapons in the multiple kiloton range were the principal type of nuclear weapon used in the Great War, delivered as bombs and missile warheads. The United States also developed man-portable nuclear catapult, the M42 Fat Man, capable of delivering miniature nuclear munitions at a range.
 * Electricity generation: The principles of nuclear fission could be harnessed for large scale power generation. A sustained reaction within a nuclear reactor produces heat, which can be used to generate steam from the working fluid and turn electricity-producing turbines. Before the advent of fusion, fission reactors became a common sight across the United States. Fission reactors were also popular choices for home energy generation, allowing families to take their homes off the grid without sacrificing their quality of life. Although portable fusion generators dominated the market, home nuclear fission reactors remained in use as late as 2077, such as the Fission Pal brand. Vaults commonly used fission generators for power generation.
 * Nuclear propulsion: With petroleum shortages, most automotive traffic ground to a halt. Alternative solutions were explored, and fission-based propulsion systems became popular. Nuclear engines were explored for use in space travel, by companies such as REPCONN Aerospace, but it was the automotive industry that adopted the technology most widely. Brands such as Corvega effectively monopolized the market with their nuclear vehicles. Fission-based engines and batteries proliferated and were commonplace even after the introduction of fusion engines. Unfortunately, without maintenance, aging engines became a hazard. After the Great War, most nuclear vehicles became essentially ticking bombs waiting to explode.
 * Portable power sources: The humble fission battery was one of the most important breakthroughs in personal power systems. Although eclipsed by fusion generators down the line, fission batteries continued to be widely used in robotics and other fields, especially in older Protectron and Mister Handy models. After the Great War, fission batteries became a popular choice among wastelanders as a cheap, readily available source of power for jury rigging electric systems, especially restoring pre-War street lights to life and providing night-time illumination.