Barriers and Issues Related to Achieving Final Disposition of Depleted Uranium

Approximately 750,000 metric tons (MT) of surplus depleted uranium (DU) in various chemical forms are stored at several Department of Energy (DOE) sites throughout the United States. Most of the DU is in the form of DU hexafluoride (DUF6) that resulted from uranium enrichment operations over the last several decades. DOE plans to convert the DUF6 to ''a more stable form'' that could be any one or combination of DU tetrafluoride (DUF4 or green salt), DU oxide (DUO3, DUO2, or DU3O8), or metal depending on the final disposition chosen for any given quantity. Barriers to final disposition of this material have existed historically and some continue today. Currently, the barriers are more related to finding uses for this material versus disposing as waste. Even though actions are beginning to convert the DUF6, ''final'' disposition of the converted material has yet to be decided. Unless beneficial uses can be implemented, DOE plans to dispose of this material as waste. This expresses the main barrier to DU disposition; DOE's strategy is to dispose unless uses can be found while the strategy should be only dispose as a last resort and make every effort to find uses. To date, only minimal research programs are underway to attempt to develop non-fuel uses for this material. Other issues requiring resolution before these inventories can reach final disposition (uses or disposal) include characterization, disposal of large quantities, storage (current and future), and treatment options. Until final disposition is accomplished, these inventories must be managed in a safe and environmentally sound manner; however, this is becoming more difficult as materials and facilities age. The most noteworthy final disposition technical issues include the development of reuse and treatment options