Depleted uranium radioactivity

Depleted uranium is composed mostly of the U-238 isotope and is considered depleted because most of its U-235 component has been removed. Natural uranium is composed of approximately 0.7% U-235 and 99.3% U-238. Depleted uranium has only about half the radioactivity of the original natural element, but radiation emanating from depleted uranium can be hazardous to human health and the environment. 

The core of the bullet can be made from a variety of materials lead is by far the most common because of its high density and the fact that it is cheap, readily obtained, and easy to fabricate. But copper, brass, bronze, aluminum, steel (sometimes hardened by heat treatment), depleted uranium, zinc, iron, tungsten, rubber, and various plastics may also be encountered. (When most of the fissile radioactive isotopes of uranium are removed from natural uranium, the residue is called depleted uranium. Depleted uranium is 67% denser than lead, and it is an ideal bullet material and is very effective in an armor-piercing role, both in small arms and larger munitions components. Because of its residual radioactivity its use is controversial.) Bullets with a lead core and a copper alloy jacket are by far the most common. 

Another military use of the actinide metals is in tank armor and armor piercing projectiles. Depleted uranium metal is an extremely dense material, for example, density of a-phase U is 19 g cm, and is only mildly radioactive, half-life of is 4.5 X 10 years. When this metal is incorporated into a projectile, the density and metallic properties allow it to penetrate deeply into heavily armored vehicles. 

Bleise, A., Danesi, P.R., Burkart, W. (2003). Properties, use and health effects of depleted uranium (DU) a general overview. J. Environ. Radioact. 64 93-112. 

Miller, A.C., Brooks, K., Stewart, M., Anderson, B., Shi, L., McClain, D., Page, N. (2003). Genomic instability in human osteoblast cells after exposure to depleted uranium delayed lethality and micronuclei formation. J. Environ. Radioact. 64 ... 

Due to the high radioactivity of the actinides, we would expect that their use for materials applications would be limited. However, a relatively benign form of uranium, known as depleted uranium (DU), has been widely used in applications... 

A very dangerous fire hazard in the form of a solid or dust when exposed to heat or flame. It can react violently with air, CI2, F2, HNO3, NO, Se, S, water, NH3, BrFs, trichloroethylene, nitryl fluoride. During storage it may form a pyrophoric surface due to effects of air and moisture. Depleted uranium (the by-product of the uranium enrichment process, with relatively low radioactivity) is used in armor-piercing shells, ship or aircraft ballast, and counterbalances. Uranium is also used in making colored ceramic glazes. 

The industrial process called enrichment is used to increase the amount of and and decrease the amount of in natural uranium. The product of this process is enriched uranium, and the leftover is depleted uranium. Enriched uranium is more radioactive than natural uranium, and natural uranium is more radioactive than depleted uranium. When enriched uranium is 97.5% pure the same weight of enriched uranium has about 75 times the radioactivity as natural uranium. This is because enriched uranium also contains which is even more radioactive than The is responsible for most of the radioactivity in enriched uranium. Natural uranium is typically about two times more radioactive than depleted uranium. Other isotopes of uranium called and are produced by industrial processes. These are also much more radioactive than natural uranium. 

Table 2-8 shows the mass equivalents for natural and depleted uranium for radiation levels that caused potential radiological effects in rats exposed once for 100 minutes to airborne 92.8% enriched uranium with an estimated specific activity of 51.6 pCi/g (Morris et al. 1989). These mass equivalent values for natural and depleted uranium for the minimal concentration of radioactivity that is expected to induce potential radiological effects are well above levels that would be expected to be inhaled or ingested. In addition, the mass equivalents for natural and depleted uranium for potential radiological effects are 3,600 and 76,500 times higher, respectively, than the occupational exposure limits (short-term exposure) recommended by the National Institute for Occupational Safety and Health (NIOSH 1997). Therefore, MRLs for uranium based on studies that used enriched uranium are inappropriate. 

Intake duration Effect Highly eniched uranium radioactivity concentration Natural uranium mass equivalent Depleted uranium mass equivalent Threshold Limit Value S... 

Value based on a highly U-enriched dioxide radioactivity concentration of 5 pCi/m and a specific activity of 0.33 pCi/g for depleted uranium... 

Depleted uranium (DU) is a by-product of the enrichment process in which about 70% of the U-235 in natural uranium is separated from U-238. The remaining uranium, DU, contains about 0.2% U-235 by weight and emits about 60% of the radioactivity of natural uranium. US military specifications designate that DU contain less than 0.3% U-235. 

Standard penetrator material [6.29]. Nevertheless, recent environmental considerations have put a strong emphasis on substituting depleted uranium by heavy metals because of its radioactivity. Efforts to improve the ballistic performance through proper processing and compositional modifications have failed [6.29,6.39]. Recent research has therefore focused on alternative matrix alloys, such as tungsten-hafhium, tungsten-uranium composites [6.29], or heavy metal alloys with a spiculating core of WC [6.41]. 

A. TB 9-1300-278 details the safe response to accidents involving army tank munitions that contain depleted uranium. CTT Task 031-503-1017, Respond to Depleted Uranium/Low Level Radioactive Materials (DULLRAM) Hazards (draft) details the response of individual soldiers to these hazards. 

Bleise a, Danes PR and Burkart W (2003) Properties, Use and Health Effects of Depleted Uranium (DU) — A General Overview. J Env Radioactivity 64 121 — 131... 

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