Groundwater calculations for depleted uranium disposed of as uranium tetrafluoride (UF{sub 4}).

Tomasko, D.

Argonne National Laboratory

关键词: Schoepite;    Radioactive Waste Disposal;    Water Tables;    Depleted Uranium;    Calculation Methods;   

DOI  :  10.2172/786917
RP-ID  :  ANL/EAD/TM-111
RP-ID  :  W-31-109-ENG-38
RP-ID  :  786917

美国|英语

来源: UNT Digital Library

【 摘 要 】

This report discusses calculations performed to estimate the impacts on groundwater from the long-term disposal of depleted uranium in the form of uranium tetrafluoride (UF{sub 4}) in a trench, vault, and mined cavity. The calculations were done for a deep groundwater system, typical of conditions in the western United States. They were performed for two initial inventories of UF{sub 4}: 500,000 and 630,000 metric tons. Disposal was in either 30- or 50-gal drums. All of the contaminant and radioactivity concentrations at the water table are predicted to be very low, even for a fairly mobile compound. In general, concentrations after 1,000 years at the water table would be about an order of magnitude greater for disposal in a deep mine than for disposal in a trench or vault. The largest activity concentration at the water table after 1,000 years would be derived from a failed mine that releases a fairly mobile and very soluble uranium complex; it would be about 8.6 x 10{sup -6} pCi/L for 500,000 metric tons of UF{sub 4} disposed of in 30-gal drums. The smallest activity concentrations at the water table after 1,000 years would, in general, be derived from a failed trench (1.2 x 10{sup -9} pCi/L), if the contaminant reached the water table as schoepite. Although all the activity concentrations at the water table after 1,000 years are predicted to be small, maximum activity concentrations could still be large, even after dilution. Maximum activity concentrations of uranium would exceed 900 pCi/L for a failed disposal facility if a very soluble and mobile uranium complex formed. If the solubility of the uranium compound was small (2.4 x 10{sup -3} g/L), the resulting activity concentrations would be small, less than 2.5 pCi/L. The estimated time for these maximum concentrations would range from 65,000 to 2,000,000 years.