Nuclear power is any nuclear technology designed to extract usable energy from atomic nuclei via controlled nuclear reactions.
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter; a modern thermonuclear weapon weighing little more than a thousand kilograms can produce an explosion comparable to the detonation of more than a billion kilograms of conventional high explosive. Thus, even single small nuclear devices no larger than traditional bombs can devastate an entire city by blast, fire and radiation. Nuclear weapons are considered weapons of mass destruction, and their use and control has been a major aspect of international policy since their debut.
Nuclear warfare, or atomic warfare, is a military conflict in which nuclear weapons are used. Compared to conventional warfare, nuclear warfare is vastly more destructive in range and extent of damage. A major nuclear exchange could have severe long-term effects, primarily from radiation release but also from possible atmospheric pollution leading to nuclear winter, that could last for decades, centuries, or even millennia after the initial attack
In the history of warfare, only two nuclear weapons have been detonated offensively, both near the end of World War II. The first was detonated on the morning of 6 August 1945, when the United States dropped a uranium gun-type device code-named "Little Boy" on the Japanese city of Hiroshima. The second was detonated three days later when the United States dropped a plutonium implosion-type device code-named "Fat Man" on the city of Nagasaki, Japan. These bombings resulted in the immediate deaths of around 120,000 people (mostly civilians) from injuries sustained from the explosion...