Depleted uranium
Depleted uranium (DU) is uranium which has had most of the fissile isotope U-235 and the highly radioactive but rare isotope U-234 removed, and consists of mostly U-238. The U-235 is concentrated into enriched uranium through the process of isotope separation for use in nuclear reactors and nuclear weapons. The remaining U-238 is 40% as radioactive as natural uranium. It is waste material from this enrichment process. During the Manhattan Project depleted uranium had the codename tubealloy, a term that is still occasionally used. Uranium is mined mainly for its U-235 content, so the excess U-238 can be obtained cheaply and is used for its extremely high density, only slightly less than that of tungsten.
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2 Civilian Applications 3 Health concerns 4 Bibliography, external links and references |
Military Applications
A major use of DU is as the head of a kinetic projectile fired to penetrate armour, so it is used by tanks and other military platforms. Depleted uranium is very dense: at 19.05 g/cmÃÂó it is 70% denser than lead, allowing it to penetrate most conventional armor. A DU projectile burns and melts as it penetrates steel, becoming 'sharper' rather than blunting. As the projectile passes through armor, the heat build-up causes it to catch fire and disintegrate into fine particles on re-encountering air, causing it to emerge from the other side of the armor accompanied by a white-hot ball of fire and a shower of molten shrapnel. DU is also used as a component in some vehicular armour, specifically in M1A1HA and M1A2 Abrams tanks built after 1998.
Armor piercing projectiles made from depleted uranium are far less expensive to manufacture than those made from tungsten, due to the fact that depleted uranium can be cast easily, whereas tungsten's tremendous hardness and very high melting point make it extremely difficult to manufacture anything from it.
Currently the US military is the primary user of DU in combat, though DU armor-piercing munitions were invented by the Soviets in the late 1970s and are still mass-produced in Russia today (as well as 17 other countries, including Pakistan). The US Army uses the DU in an alloy with around 3.5% titanium. It is used by the US Army in 120 mm or 105 mm caliber by the M1 Abrams and M60A3 tanks and in 25 mm by the M919 mounted on the M2 Bradley and the LAV-AT; some late-production Abrams tanks have DU rods as reinforcements as part of its armour plating in the front of the hull and the front of the turret. The US Navy uses it in its 20 mm CIWS and the 25mm Mk 38 machine gun. The Air Force uses it in 30 mm caliber on the A-10 Thunderbolt II and the Marine Corps in 25 mm on their AV-8B Harrier and also in the 20mm electric Gatling gun mounted on AH-1 helicopter gunships. The Russian military mainly uses DU munitions in tank main gun ammunition, mostly for the 115mm guns in the T62 tank and the 125mm guns in the T64, T72, T80, and T90 tanks. DU munitions (in the form of tank and naval artillery rounds) are also deployed by the armed forces of the UK, Israel, France, Japan, China, Russia, Germany, Pakistan, and many other countries.
Environmental groups have raised concerns about the use of this material; arguing that not only is it dangerously radioactive, but it is also as toxic as lead. Such issues are of concern to those fired upon by DU weapons, to those protected by DU armour-plating; and to civilians and troops operating in a theatre where DU is used. The health effects of depleted uranium have been postulated to be one of the possible causes of Gulf war syndrome. This possibility has been widely denied by a number of government officials, most of whom deny that DU is dangerously radioactive.
Studies of scientific bodies have resulted in mixed conclusions. Studies showing detrimental health affects have claimed the following:
Civilian Applications
Depleted uranium is also used in sailboat keels, as counterweights in oil drills, and in other places where there is a need to place a weight that occupies as little space as possible, such as in aircraft ballast. Tungsten could also be used, but it is extremely difficult to manufacture anything from tungsten due to its tremendous hardness and high melting point, so anything made from tungsten is extremely expensive.Health concerns
"The most important concern is the potential for future groundwater contamination by corroding penetrators (ammunition tips made out of DU). The penetrators recovered by the UNEP team had decreased in mass by 10-15% due to corrosion. This rapid corrosion speed underlines the importance of monitoring the water quality at the DU sites on an annual basis."
These facts together may indicate that DU ammunition is actually quite a health problem and endangers the civilian population if left on the battlefield. However, other studies have shown that DU ammunition has no measurable detrimental health effects, either in the short or long term. Critics of these studies point to the fact that they come primarily from the US and UK -- both supporters of DU. However, the Geneva-based International Atomic Energy Agency also reports, "based on credible scientific evidence, there is no proven link between DU exposure and increases in human cancers or other significant health or environmental impacts" [1]. The US military watchdog group Federation of American Scientists has come to similar conclusions.Bibliography, external links and references