Uranium

Uses

Uranium’s defining modern use is as nuclear fuel: uranium-235, enriched to usable concentrations, sustains the chain reactions that power nuclear plants generating electricity for hundreds of millions of people, and in far more concentrated form formed the core of the first atomic weapons. Depleted uranium — what’s left after enrichment, mostly uranium-238 — is dense enough to be used in armor-piercing ammunition and as counterweights in aircraft, applications that rely on its weight rather than its radioactivity.

Long before any of that was possible, uranium had a much quieter role: its compounds were prized for coloring glass and ceramic glazes a distinctive yellow-green, an industry that predates any understanding of radioactivity and largely ended once the risks became clear.

History

Uranium was identified in 1789 by German chemist Martin Heinrich Klaproth, who found a new element in the mineral pitchblende and named it after the planet Uranus. The pure metal wasn’t isolated until 1841, by French chemist Eugène-Melchior Péligot. Uranium’s most consequential chapter began in 1896, when Henri Becquerel noticed that uranium salts fogged photographic plates without any light source — the discovery of radioactivity. Decades later, the 1938 discovery that uranium nuclei could be split, and the realization that this fission could release enormous energy, set in motion the research that led to both nuclear power and nuclear weapons.