Depleted Uranium and Uranium Alloy Properties
Developed for the U.S. Department of Energy by Pacific Northwest National Laboratory
Environmental, Safety & Health Considerations from ref. 1
While depleted uranium (DU) can be melted, fabricated and machined using conventional practices, its mild radioactivity, chemical toxicity and pyrophoricity require that special precautions be taken in processing.
DU is only mildly radioactive and is listed as a low specific-activity material in shipping regulations. The primary radiological hazards associated with this material are beta and alpha emissions. The beta dose rate at the surface of a uranium slug is 0.23 rad/h. The dose rate of this modestly penetrating radiation decreases dramatically with distance from the source due to absorption in the air and geometric effects. As a result, working near Du and normal handling of this material does not result in excessive exposures. Nonetheless, significant exposures could result from continuous very close contact, so unnecessary contact should be avoided.
Alpha radiation is also emitted by DU, but this nonpenetrating radiation is not a hazard unless the finely divided uranium particles become airborne and are inhaled where the alpha radiation can damage sensitive lung tissue. Hence, it is important to ensure that airborne concentrations remain below the OSHA standard of 0.25 mg/m3 of air.
Depleted uranium is about as chemically toxic as other heavy metals such as lead. Problems can best be avoided by careful control of any finely divided material and by good personal hygiene.
Finely divided uranium is pyrophoric; therefore machining chips and grinding residue must be handled carefully to avoid the danger of fire. These hazards can be minimized by using liberal amounts of machining fluid, keeping machining waste submerged in water or oil, removing chips from tools and work areas frequently, and avoiding mixed metal chips. Dry power fire extinguishers should be readily available. Never use water on uranium fires.
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