Wiktionary
n. uranium that contains a reduced (depleted) amount of the fissile isotope U-235 compared to natural uranium; it is used in applications where radioactivity in not needed
Wikipedia
Depleted uranium (DU; also referred to in the past as Q-metal, depletalloy or D-38) is uranium with a lower content of the fissile isotope U-235 than natural uranium. (Natural uranium contains about 0.72% of its fissile isotope U-235, while the DU used by the U.S. Department of Defense contain 0.3% U-235 or less). Uses of DU take advantage of its very high density of 19.1 g/cm (68.4% denser than lead). Civilian uses include counterweights in aircraft, radiation shielding in medical radiation therapy and industrial radiography equipment, and containers for transporting radioactive materials. Military uses include armor plating and armor-piercing projectiles.
Most depleted uranium arises as a by-product of the production of enriched uranium for use as fuel in nuclear reactors and in the manufacture of nuclear weapons. Enrichment processes generate uranium with a higher-than-natural concentration of lower- mass-number uranium isotopes (in particular U-235, which is the uranium isotope supporting the fission chain reaction) with the bulk of the feed ending up as depleted uranium, in some cases with mass fractions of U-235 and U-234 less than a third of those in natural uranium. Since U-238 has a much longer half-life than the lighter isotopes, DU emits less alpha radiation than natural uranium. DU from nuclear reprocessing has different isotopic ratios from enrichmentâby-product DU, from which it can be distinguished by the presence of U-236.
DU used in US munitions has 60% of the radioactivity of natural uranium. Trace transuranics (another indicator of the use of reprocessed material) have been reported to be present in some US tank armor.
The use of DU in munitions is controversial because of concerns about potential long-term health effects. Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by exposure to uranium, a toxic metal. It is only weakly radioactive because of its long radioactive half-life (4.468 billion years for uranium-238, 700 million years for uranium-235; or 1 part per million every and years, respectively). The biological half-life (the average time it takes for the human body to eliminate half the amount in the body) for uranium is about 15 days. The aerosol or spallation frangible powder produced by impact and combustion of depleted uranium munitions can potentially contaminate wide areas around the impact sites, leading to possible inhalation by human beings.
The actual level of acute and chronic toxicity of DU is also controversial. Several studies using cultured cells and laboratory rodents suggest the possibility of leukemogenic, genetic, reproductive, and neurological effects from chronic exposure. A 2005 epidemiology review concluded: "In aggregate the human epidemiological evidence is consistent with increased risk of birth defects in offspring of persons exposed to DU."
Usage examples of "depleted uranium".
The use of depleted uranium itself had been a close run thing in the Bundestag, the German Parliament.
The counter tops are made of depleted uranium, which may not be strong enough for weapons use but is still warm to the touch.
With an unnoticed whine the first teardrop-shaped bead of depleted uranium was lofted into place.
But at the end it cut through the thin shell of depleted uranium surrounding the antimatter core with relative ease.
This time, though, the smaller Lamprey was effectively killed by the kinetic energy of the depleted uranium warhead passing through its engine-room.
Connors answered, sliding down a trench, then lifting his head and arm over the berm just long enough to donate a couple of thousand depleted uranium teardrops to the Posleen.
Rock said, staring down into the chamber with the hot cell made of depleted uranium-238.
A crater near the center, still steaming, marked where the orbital bombardment had dropped a fair-sized slug of depleted uranium with a yield of a few kilotons or so, but the place had been worked over very thoroughly since then, leaving an eerie, cratered-moon appearance, like the two-dimensional photos hed seen once of the region called no-mans land between the trenches of an ancient, prespaceflight war on old Earth.
When the depleted uranium penetrator left the muzzle, it was traveling at over a mile a second.
A depleted uranium slug had passed through the Huey's deck, taken off the man's leg, then passed through the bulkhead aft, and Thran had not even felt the shock.
For tonight's mission, Richardson's flight had a full load of depleted uranium slugs for their Avenger cannons and a pair of Rockeye cluster bomb canisters, additional antitank weapons.
Robbed of much of its kinetic energy by its high-G maneuver to avoid the Hellbore bolt, it strikes with only a fraction of the energy a five-meter rod of depleted uranium was designed to carry .
But it's still got depleted uranium penetrators and I think you'd be surprised at what you can do in a Wyvern.
The big Catling gun on the deck of the Enterprise opens up again and fires another meteorite of depleted uranium slugs into the side of an unoccupied barge about twenty feet from Hiro.
The depleted uranium casing of the warhead punched straight through the 300mm-thick armor and spewed globules of molten metal into the interior.