Short answers, pulled from the story.
Uranium was discovered in 1789 by German chemist Martin Heinrich Klaproth, who precipitated a yellow compound from pitchblende dissolved in nitric acid and named the element after the planet Uranus. The actual metal was first isolated in 1841 by Eugène-Melchior Péligot, Professor of Analytical Chemistry at the Conservatoire National des Arts et Métiers in Paris.
Uranium-235 makes up 0.71% of natural uranium and is fissile, meaning it splits when struck by slow neutrons and can sustain a nuclear chain reaction. Uranium-238 makes up 99.28% of natural uranium, requires fast neutrons to fission, and is primarily used as a source material that can be converted into fissile plutonium-239 inside a nuclear reactor.
The Hiroshima bomb, called Little Boy, used highly enriched uranium-235 as its fissile material and detonated on the 6th of August 1945 with a yield equivalent to 12,500 tonnes of TNT, destroying nearly 50,000 buildings and killing about 75,000 people. As little as 15 pounds of uranium-235 is sufficient to build an atomic bomb.
Natural nuclear fission reactors are ancient geological formations where self-sustaining fission chain reactions occurred without human involvement. French physicist Francis Perrin discovered 15 such reactors in 1972 at the Oklo mine in Gabon, Africa, in ore deposits 1.7 billion years old, when uranium-235 was abundant enough at around 3% to sustain chain reactions.
Depleted uranium is used in kinetic energy penetrating projectiles alloyed with 1-2% titanium or molybdenum, in tank armor plating, as shielding in containers for radioactive materials, as counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles, and in inertial guidance systems and gyroscopic compasses, where its high density and machinability are key advantages.
Worldwide uranium production in 2024 reached 60,213 tonnes. Kazakhstan led with 23,270 tonnes, or 39% of global output, followed by Canada at 14,309 tonnes, Namibia at 7,333 tonnes, Australia at 4,598 tonnes, Uzbekistan at 4,000 tonnes, and Russia at 2,738 tonnes.