What is uranium?
Uranium (chemical symbol U) is a naturally occurring radioactive element. In its pure form it is a silver-coloured heavy metal, similar to lead, cadmium and tungsten. Like tungsten it is very dense, about 19 grams per cubic centimetre, 70% more dense than lead. It is so dense a small 10-centimetre cube would weigh 20 kilograms. The International Atomic Energy Agency (IAEA) defines uranium as a Low Specific Activity material. In its natural state, it consists of three isotopes (U-234, U-235 and U-238). Other isotopes that cannot be found in natural uranium are U-232, U-233, U-236 and U-237. The table below shows the fraction by weight of the three isotopes in any quantity of natural uranium, their half lives, and specific activity. The half life of a radioactive isotope is the time taken for it to decay to half of its original amount of radioactivity. The specific activity is the activity per unit mass of a particular radionuclide and is used as a measure of how radioactive a radionucli
Uranium is a radioactive element that occurs naturally in low concentrations (a few parts per million) in soil, rock, and surface and groundwater. It is the heaviest naturally occurring element, with an atomic number of 92. Uranium in its pure form is a silver-colored heavy metal that is nearly twice as dense as lead. In nature, uranium atoms exist as several isotopes: primarily uranium-238, uranium-235, and a very small amount of uranium-234. (Isotopes are different forms of an element that have the same number of protons in the nucleus, but a different number of neutrons.) In a typical sample of natural uranium, most of the mass (99.27%) consists of atoms of uranium-238. About 0.72% of the mass consists of atoms of uranium-235, and a very small amount (0.0055% by mass) is uranium-234. Uranium is naturally radioactive, which means that atoms of uranium are unstable and decay by emitting particles and energy. Uranium decays very slowly by emitting an alpha particle. The half-life of ur
Uranium is a very dense, radioactive metallic element, naturally occurring in most rocks, soil, and even in the ocean! It is not at all rare, and in fact occurs more commonly than gold, silver or mercury. Uranium is found as an oxide or complex salt in minerals such as pitchblende and carnotite. It is formed from volcanic activity and has an average concentration in the earth’s crust of about 2 parts per million. Uranium was named after the planet Uranus, although the metal is not very common in the solar system. It does, however, provide the main source of heat inside the earth. Uranium is mined for many different purposes and has been used to produce energy for more than forty years. Greater technical detail can be found on this topic by searching through the listed briefing papers and education resources at www.uic.com.au.
Uranium is a common, naturally occurring element, present in low amounts in rocks, soil, air, surface water and groundwater. Uranium is naturally radioactive, like many other naturally occurring radioactive elements in nature. Natural uranium exists as a mixture of three types, or isotopes, called U-234 (234U), U-235 (235U), and U-238 (238U). All three types of uranium behave the same chemically, but they have different radioactive properties. U-238 is the most common type of uranium on earth and is the least radioactive. More than 99% of naturally occurring uranium is U-238. U-234 is the most radioactive type of uranium. U-235 is used as a fuel in power plants and weapons. Radioactive elements are unstable and they become stable by giving off energy, a process called radioactive decay. All three uranium isotopes go through radioactive decay primarily by giving off what is called an alpha particle. These particles have very low penetrating ability and cannot pass through solid objects
