Today according to my A2Z theme, I’m telling you the story of one of the most important discoveries that changed the face of our world forever. The Uranium Discovery. It is not actually an invention, but it is more important than most inventions.
Uranium, “the rock that nuked the world” was considered a useless material until very recently in human history, when it quite literally exploded into the public consciousness. Uranium was discovered in the ancient world, but was thrown out as a tailing from silver mining. It wasn’t until the eighteenth century that any practical use for uranium was discovered, when it was used as an agent to color glass.
In 1972 the French physicist Francis Perrin discovered fifteen ancient and no longer active natural nuclear fission reactors in three separate ore deposits at the Oklo mine in Gabon, West Africa, collectively known as the Oklo Fossil Reactors. The ore deposit is 1.7 billion years old; then, uranium-235 constituted about 3% of the total uranium on Earth. This is high enough to permit a sustained nuclear fission chain reaction to occur, provided other supporting conditions exist. The capacity of the surrounding sediment to contain the nuclear waste products has been cited by the U.S. federal government as supporting evidence for the feasibility to store spent nuclear fuel at the Yucca Mountain nuclear waste repository.
In 1789, a chemist named Martin Klaproth formally discovered the properties of Uranium, naming it after a recently discovered planet in the solar system (Uranus – named after the primordial Greek god of the sky). But in 1896 that the destructive properties of the element were named, by a science fiction writer named Herbert George Wells, who came up with a story called “The World Set Free” featuring an element that when broken apart, yielded an incredible amount of energy. He had inadvertently predicted just what uranium would be known for, a few short decades later. (I mentioned this part previously in my post about novels).
A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons from the elements produced). The fission products were at first mistaken for new elements of atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened ausonium and hesperium, respectively. The experiments leading to the discovery of uranium’s ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn’s laboratory in Berlin. Lise Meitner and her nephew, the physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process “nuclear fission”. Soon after, Fermi hypothesized that the fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of the rare uranium isotope uranium-235. Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235, is also fissionable by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and nuclear power.
On 2 December 1942, as part of the Manhattan Project, another team led by Enrico Fermi was able to initiate the first artificial self-sustained nuclear chain reaction, Chicago Pile-1. Working in a lab below the stands of Stagg Field at the University of Chicago, the team created the conditions needed for such a reaction by piling together 400 short tons (360 metric tons) of graphite, 58 short tons (53 metric tons) of uranium oxide, and six short tons (5.5 metric tons) of uranium metal, a majority of which was supplied by Westinghouse Lamp Plant in a makeshift production process.
This is a brief history of Uranium, but why is it so important? No one of course can deny the huge effect of the famous “Manhattan Project” on the world. The Super-Destruction weapons are no deciding who rules the world (from the military point of view). The nuclear bombs wouldn’t be here without using Uranium from which Marie Curie got the Radium. But these are not happy uses of Uranium, right?
Uranium is also used in our normal lives. It is mainly used to fuel nuclear power plants. One kilogram of uranium-235 can theoretically produce about 20 terajoules of energy (2×1013 joules), assuming complete fission; as much energy as 1500 tonnes of coal.
Uranium was also used in photographic chemicals (especially uranium nitrate as a toner), in lamp filaments, to improve the appearance of dentures, and in the leather and wood industries for stains and dyes. Uranium salts are mordants of silk or wool. Uranyl acetate and uranyl formate are used as electron-dense “stains” in transmission electron microscopy, to increase the contrast of biological specimens in ultrathin sections and in negative staining of viruses, isolated cell organelles and macromolecules.
The discovery of the radioactivity of uranium ushered in additional scientific and practical uses of the element. The long half-life of the isotope uranium-238 (4.51×109 years) makes it well-suited for use in estimating the age of the earliest igneous rocks and for other types of radiometric dating, including uranium-thorium dating, uranium-lead dating and uranium-uranium dating. Uranium metal is used for X-ray targets in the making of high-energy X-rays.