Manufacturing of Products Containing Depleted Uranium
Discussion of risks and possible impacts associated with fabrication of representative products containing depleted uranium.
Beneficial Uses Risk Evaluation
The Department has initiated the Depleted Uranium Uses Research and Development Program to explore the potential beneficial uses of the depleted uranium (DU), fluorine, and empty carbon steel DUF6 storage cylinders for effective use of resources and to achieve cost savings to the government. A number of tasks have been initiated related to uses of DU as a shielding material, catalyst, and as a semi-conductor material in electronic devices. An evaluation of the risks associated with the release and subsequent use of conversion products would be required before DOE authorized release of any products with potential residual contamination into commerce, in accordance with DOE Order 5400.5.
The PEIS evaluated the general impacts of fabrication of representative products containing depleted uranium, specifically, spent nuclear fuel storage casks containing depleted uranium oxide or metal as shielding material. Since the fluorine component would have been removed during conversion, the risk associated with storage and handling of the oxide or metal would be greatly decreased. Under normal operating conditions, there would be a small increase in cancer risk for workers due to exposure to external radiation from the uranium oxide or metal; however, good work practices would minimize the exposure and the risk.
The PEIS evaluated several hypothetical accident scenarios at a depleted uranium product fabrication facility, including container drops, process accidents, earthquakes, floods, tornadoes, as well as others. Even under extreme accident conditions, such as if the manufacturing facility were damaged in an earthquake, the risk of immediate chemical injury to the general public and to workers from exposure to released uranium oxide or metal was found to be very small. The most serious accident for a manufacturing facility evaluated in the PEIS was an earthquake damaging the facility, resulting in failure of several uranium metal furnaces. The probability of earthquakes depends on the location of the facility, and the probability of damage depends on the structural characteristics of the buildings. In the PEIS, the estimated frequency of this type of accident at a manufacturing facility was estimated to be less than once in one million years. However, if such an extremely low frequency accident did occur, it was estimated that 35 pounds of uranium metal could be released, resulting in 1 member of the general public around the manufacturing facility experiencing adverse effects from chemical exposures (mostly mild and temporary effects, such as respiratory irritation or temporary decrease in kidney function), with no irreversible adverse effects or fatalities expected. In addition, irreversible or fatal effects among workers very near the accident scene would be possible. Increased cancer risk from radiation exposure from such an accident would be relatively small; the most exposed individual would have an increased lifetime cancer risk of about 1 x 10-4 (1 chance in 10,000).
It should be noted that the PEIS analysis of accidents was based on representative plant designs and representative sites. Conservative assumptions were used so as not to underestimate potential impacts. The types of accidents and probabilities of their occurrence will depend on the specific designs and locations of the actual fabrication facilities and will be evaluated thoroughly during the design and licensing process.
(For more details on risks from manufacturing, see also Appendix H of the PEIS.)