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Uranium What is Uranium Uranium Geology Uranium Deposits Uranium Resources Uranium Mining Uranium Logs

What is Uranium?

UraniumUranium was formed in our galaxy by supernova events billions of years ago. While it is not thought to be common in the solar system, today its slow radioactive decay provides the main source of heat inside the Earth's crust. Uranium is a very heavy metal which can be used as an abundant source of concentrated energy. It usually occurs as an oxide mineral. The primary uranium mineral is uraninite (UO2).

Uranium was discovered in 1789 by Martin Klaproth, a German chemist, in a mineral ore known as pitchblende. It was named after the planet Uranus, which had been discovered eight years earlier.

Uranium metal is about 60 percent denser than lead and almost as dense as gold. It occurs in trace amounts nearly everywhere on the planet, even in seawater.

Clean Energy Source

Nuclear energy, produced from uranium, is recognized as a practical, inexpensive and clean source of energy. A typical 1,000 megawatt reactor can provide enough electricty for a modern city of up to 1 million people. Nuclear power is reliable and power plants emit no carbon dioxide. The emissions coming from the massive towers of a nuclear plant are actually water vapor. Nuclear power boasts the best capacity factor of all forms of electrical generation. At capacity, a nuclear power plant can run at above 90 percent; a coal-fired plant runs at about 64 percent, natural gas power plant at 43 percent and hydroelectric plant at 40 percent.

In a nuclear-fueled power plant, water is turned into steam, which drives turbine generators to produce electricity. The main difference between a nuclear power plant and a coal or natural gas-fired power plant is the source of heat. At a nuclear power plant, the heat to make the steam is created when uranium atoms split by a process called fission. There is no combustion in a nuclear reactor.

Properties of Uranium

Uranium occurs naturally as several different isotopes (elements with the same number of protons but a different number of neutrons). More than 99 percent of all uranium is 238U (atomic weight 238, or about 238 times the weight of one hydrogen atom, and 13 times denser than the same volume of water), and less than 1 percent is in the form 235U; other uranium isotopes are very rare. Power Plant

The atomic number of uranium is 92, as it contains 92 protons in its nucleus. The rest of the particles in the nucleus are neutrons; 146 in 238U and 143 in 235U. The 235U isotope is less stable and decays more rapidly than 238U, the isotope used as fuel in nuclear reactors.

In the natural environment, uranium is found as 238U (99.284 percent of all naturally occurring uranium), 235U (0.711 percent), and a very small amount of 234U (0.0058 percent).

Several other isotopes of uranium are known but are very rare and usually very short-lived. Uranium decays slowly by emitting alpha particles. An alpha particle emitted from the uranium nucleus is positively charged and made up of two protons and two neutrons, which is physically and chemically identical to a helium nucleus.

The half-life of 238U is about 4.47 billion years and that of 235U is 704 million years, making them useful in dating the age of geologic events.

Uranium Atom

The nucleus of the 235U atom comprises 92 protons and 143 neutrons (92 + 143 = 235). When the nucleus of a 235U atom captures a moving neutron it splits in two (fission reaction) and releases some energy in the form of heat, and two or three additional neutrons are thrown off. If enough of these expelled neutrons cause the nuclei of other 235U atoms to split, releasing further neutrons, a fission 'chain reaction' can be achieved. When this happens repeatedly, many millions of times, a very large amount of heat is produced from a relatively small amount of uranium.

Military Uses
  • Nuclear reactors to power naval vessels
  • Nuclear (atomic) warheads
  • Chemical catalysts
  • Military aircrafts and space vessels
  • Shielding materials
  • Civil Uses
  • Electrical generation
  • Shielding for industrial radiography cameras
  • Radioactive material used in counterweights for applications for sailboats
  • Aircrafts
  • Oil wells
  • Inertial guidance systems and compasses
  • Source: World Nuclear Organization

    Bob Gregory (307) 766-2286 Ext. 237