In a nuclear reactor, this heat is used to boil water, creating steam that turns a turbine to generate power, and the reaction is controlled by materials such as cadmium or boron, which can absorb extra neutrons to take them out of the reaction chain.
In a fission bomb like the one that destroyed Hiroshima, the reaction goes supercritical. What this means is the fission occurs at an ever-increasing rate. These supercritical reactions release massive amounts of energy: The blast that destroyed Hiroshima had the power of an estimated 15 kilotons of TNT, all created with less than a kilogram 2. To make uranium fission more efficient, nuclear engineers enrich it. Natural uranium is only about 0. The rest is U To increase the proportion of U, engineers either gasify the uranium to separate out the isotopes or use centrifuges.
According to the World Nuclear Association, most enriched uranium for nuclear power plants is made up of between 3 percent and 5 percent U On the other end of the scale is depleted uranium, which is used for tank armor and to make bullets. Depleted uranium is what's left over after enriched uranium is spent at a power plant. It's about 40 percent less radioactive than natural uranium, according to the U. Department of Veterans Affairs.
This depleted uranium is only dangerous if it is inhaled, ingested or enters the body in a shooting or explosion. Given its importance in nuclear fuel, researchers are keenly interested in how uranium functions — particularly during a meltdown. Meltdowns occur when the cooling systems around a reactor fail and the heat generated by the fission reactions in the reactor core melts the fuel. This happened during the nuclear disaster at the Chernobyl nuclear power plant , resulting in a radioactive blob dubbed "the Elephant's foot.
Understanding how nuclear fuels act when they melt is crucial for nuclear engineers building containment vessels, said John Parise, a chemist and mineralogist at Stony Brook University and Brookhaven National Laboratory. In November , Parise and colleagues from Argonne National Lab and other institutions published a paper in the journal Science that elucidated the inner workings of melted uranium dioxide, a major component of nuclear fuel, for the first time.
Uranium dioxide doesn't melt until temperatures top 5, F 3, C , so it's hard to measure what happens when the material goes liquid, Parise told Live Science — there's just no container tough enough. The property of uranium important for nuclear weapons and nuclear power is its ability to fission, or split into two lighter fragments when bombarded with neutrons releasing energy in the process. Of the naturally-occuring uranium isotopes, only uranium can sustain a chain reaction— a reaction in which each fission produces enough neutrons to trigger another, so that the fission process is maintained without any external source of neutrons.
Traditionally, uranium has been extracted from open-pits and underground mines. In the past decade, alternative techniques such in-situ leach mining, in which solutions are injected into underground deposits to dissolve uranium, have become more widely used.
Most mines in the U. The milling refining process extracts uranium oxide U 3 O 8 from ore to form yellowcake, a yellow or brown powder that contains about 90 percent uranium oxide. In-situ leach mining leaves the unusable portion in the ground, it does not generate this form of waste. The total volume of mill tailings generated in the U. Moreover, the half-lives of the principal radioactive components of mill tailings, thorium and radium are long, being about 75, years and 1, years respectively.
The most serious health hazard associated with uranium mining is lung cancer due to inhaling uranium decay products. Uranium mill tailings contain radioactive materials, notably radium, and heavy metals e.
Mining and milling operations in the U. For example, nearly one third of all mill tailings from abandoned mill operations are on lands of the Navajo nation alone. Others continue to suffer the effects of land and water contamination due to seepage and spills from tailings piles. Uranium is generally used in reactors in the form of uranium dioxide UO 2 or uranium metal; nuclear weapons use the metallic form. Production of uranium dioxide or metal requires chemical processing of yellowcake.
Further, most civilian and many military reactors require uranium that has a higher proportion of uranium than present in natural uranium.
I'm Chris Smith, thank you for listening and goodbye. Chemistry in its element is brought to you by the Royal Society of Chemistry and produced by thenakedscientists. There's more information and other episodes of Chemistry in its element on our website at chemistryworld.
Click here to view videos about Uranium. View videos about. Help Text. Learn Chemistry : Your single route to hundreds of free-to-access chemistry teaching resources. We hope that you enjoy your visit to this Site. We welcome your feedback. Data W. Haynes, ed. Version 1. Coursey, D. Schwab, J. Tsai, and R. Dragoset, Atomic Weights and Isotopic Compositions version 4.
Periodic Table of Videos , accessed December Podcasts Produced by The Naked Scientists. Download our free Periodic Table app for mobile phones and tablets.
Explore all elements. D Dysprosium Dubnium Darmstadtium. E Europium Erbium Einsteinium. F Fluorine Francium Fermium Flerovium. G Gallium Germanium Gadolinium Gold. I Iron Indium Iodine Iridium. K Krypton. O Oxygen Osmium Oganesson. U Uranium. V Vanadium. X Xenon. Y Yttrium Ytterbium. Z Zinc Zirconium. Membership Become a member Connect with others Supporting individuals Supporting organisations Manage my membership.
Facebook Twitter LinkedIn Youtube. Discovery date. Discovered by. Martin Heinrich Klaproth. Origin of the name. Uranium was named after the planet Uranus. Melting point. Boiling point. Atomic number. Relative atomic mass. Key isotopes. Electron configuration. CAS number. ChemSpider ID. ChemSpider is a free chemical structure database. Electronegativity Pauling scale. Common oxidation states. Atomic mass. Half life. Mode of decay. Relative supply risk. Crustal abundance ppm.
Top 3 producers. Top 3 reserve holders. Political stability of top producer. Political stability of top reserve holder. Young's modulus GPa. Shear modulus GPa. Bulk modulus GPa. Vapour pressure. It has provided the world with many positive innovations in the medical and industrial sectors, and also has been negatively scrutinized for its use in and production of weapons products.
In medicine they are used for diagnosis and research, with about 1 in 2 people in the Western world likely to experience the benefits of nuclear medicine in their lifetime. Radioisotopes are also used for the food industry , as they can preserve food, kill parasites, and control the ripening of fruits and vegetables.
Industrially they are used for safety as they can detect leaks, provide analysis of minerals and fuels, and uranium can work as a radiation shield.
The energy from uranium, along with its by-product of plutonium, have a history for producing disastrous consequences. The key difference between nuclear weapons and fuel used in reactors is the grade of the fuel. The first nuclear bomb ever detonated in combat was called the "Little Boy", developed during the Manhattan Project and detonated over Hiroshima. It used two pieces of sub-critical Uranium, which upon detonation smashed into each other, producing an uncontrollable nuclear chain reaction and yielding an energy release equal to 13 short tons of TNT.
The use of these bombs has been extremely controversial since their detonation, as they killed hundreds of thousands of people. This destructive use of nuclear power has probably affected how people have viewed the rare few nuclear disasters in Chernobyl , Fukushima , and Three Mile Island. Overall, this has left a very negative view of nuclear energy in a large portion of the general population. The video below is from the University of Nottingham's periodic videos project.
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