Uranium is a very heavy metal which can be used as an abundant source of concentrated energy. It was discovered in 1789 by Martin Klaproth, a German chemist, in the mineral called pitchblende. It was named after the planet Uranus, which had been discovered eight years earlier.
It was around the time of Superman's birth, while all of Krypton was busily engaged in preparations for the planet-wide pageantry scheduled to mark the upcoming anniversary of "the 10,000th year" of Kryptonian civilization (Act No. 223, Dec 1956: "The First Superman of Krypton"), that Jor-El made what was at once the most momentous and most calamitous discovery of his scientific career: the discovery that Krypton's uranium core, which for untold ages [had] been building a cycle of chain-reactions," was on the verge of unleashing a planetary cataclysm, that "soon every atom on [the] planet would explode like one colossal atomic bomb!" (S No. 61/3, Nov/Dec 1949: "Superman Returns to Krypton!").
In July-August 1951, R24 and his henchmen are engaged in the illicit mining and smuggling of uranium from the fringes of the federal government uranium mine at Grass Mountain, north of Metropolis (S No. 71/1: â€œClark Kentâ€™s Super-Masquerade!â€).
Professor Weirton is the inventor of a strange "cabinet-like machine" which, by means of "specially filtered uranium rays...can give any person superpowers for a period of 24 hours, by speeding the evolutionary process and putting him 1,000,000 years ahead of his time!" (Act No. 163, Dec 1951: "The Girl of Tomorrow").
In May 1957, Superman saves the doomed planet Vergo by gathering together a planet-sized sphere of space-drift rich in uranium ore, and sending it hurtling into the dying ember of the Vergoan sun, which is revitalized by the exploding uranium (S No. 113, May 1957: chs. 1-3 â€The Superman of the Pastâ€; â€œThe Secret of the Towersâ€; â€œThe Superman of the Presentâ€).
Xenon, the so-called "twin world of Krypton," also menaced by earthquakes and volcanic eruptions in February 1958, heralding the onset of a chain reaction within its uranium core identical to the one that once doomed Krypton (S No. 119: â€œThe Second Superman!â€ chs. 1-3-â€œThe World That Was Kryptonâ€™s Twinâ€; â€œA Double for Supermanâ€; â€œSupermanâ€™s Mightiest Questâ€).
The great giant ape Titano is created when normal-sized chimpanzee named Toto is launched into space aboard an experimental orbiting satellite for a week. While in space, the animal's capsule was bombarded by intense radiation emanating from the collision of two meteorites ... one containing traces of uranium, the other being purely composed of Green Kryptonite. Upon the capsule's return to Earth, Toto amazingly grew to a height of more than 40 feet (S No. 127/3, Feb 1959: "Titano the Super-Ape").