Environment News Service

AmeriScan: July 19, 2000


UPTON, New York, July 19, 2000 (ENS) - Scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have been awarded a patent for a process that encapsulates depleted uranium oxides in thermoplastic polymers. The process converts depleted uranium to a form the researchers say is stable and safe for long term disposal or reuse. The encapsulated uranium could be used in the production of radiation shielding and counter weights for airplanes, helicopters and ships, the scientists said. Depleted uranium (DU) is a by-product of enriching uranium ore to make fuel for nuclear reactors. Storing DU requires labor intensive and expensive maintenance. The Brookhaven Lab process converts uranium oxide powder from a reactive form through chemical processing, and combines it with a thermoplastic binder. The final product can be formed into shapes and is cooled to form a dense solid.

BNL's patented process for encapsulation requires simultaneous heating and mixing of depleted uranium powders and non-biodegradable thermoplastic polymers such as polyethylene or polypropylene. Virgin or recycled polymers can be used. The result is a mixture of depleted uranium and molten thermoplastic polymer, which can be molded into any shape. The final form emits very low levels of radioactivity, and the dense material would make good shielding against gamma or neutron radiation, the scientists said. "By creating safe, secondary end use products from these materials, we are addressing health and safety, environmental protection, and waste reduction issues," said Paul Kalb, senior research engineer Brookhaven's Environmental Research and Technology Division.

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