Environmental Risks of Depleted UF6 Storage
Discussion of the potential environmental impacts from storage of depleted UF6 at the three current storage sites, as well as potential impacts from the storage of depleted uranium after conversion to an oxide form.
Impacts Analyzed in the PEIS
The PEIS included an analysis of the potential environmental impacts from continuing to store depleted UF6 cylinders at the three current storage sites, as well as potential impacts from the storage of depleted uranium after conversion to an oxide form.
Impacts from Continued Storage of UF6 Cylinders
Continued storage of the UF6 cylinders would require extending the use of a total of about 100 acres of land currently used to store the cylinders. The PEIS analysis indicated that if continued cylinder maintenance and painting are effective in controlling corrosion, as expected, impacts to the environment, such as air or groundwater contamination, would be kept within regulatory standards at all storage sites; essentially no adverse impacts would be expected during the approximately 40 time frame evaluated in the PEIS.
However, the potential for adverse impacts from continued cylinder storage was identified for air and groundwater quality, if worst-case conditions were assumed (i.e., that cylinder maintenance and painting activities would not reduce cylinder corrosion rates). Under these conditions, it is possible that cylinder breaches could result in HF air concentrations greater than the regulatory standard level at the ETTP storage site around the year 2020; HF concentrations at the Paducah and Portsmouth sites were estimated to remain within applicable standards or guidelines. Additionally, uranium concentrations in groundwater could exceed the 20 µg/L guideline level at all three sites at some time in the future (earliest about the year 2100 at the Paducah site). However, if continued cylinder maintenance and painting are effective in controlling corrosion, as expected, air and groundwater concentrations of pollutants related to continued storage would be kept within regulatory standards at all storage sites.
No other adverse environmental impacts were identified in the PEIS from continued cylinder storage. Socioeconomic impacts were evaluated in terms of jobs and income generated, which are considered positive impacts. Continued storage was estimated to result in 140 direct jobs and generation of $6 million in direct income per operational year at all three of the storage sites combined.
(For more details on the environmental risks from continued storage, see also Section 2.4 and Appendix D of the PEIS.)
Impacts from Storage of Depleted Uranium Oxide
The PEIS evaluated the long-term storage of depleted uranium oxide in three different types of facilities, aboveground buildings, below-ground vaults, and a mine. For the purposes of the PEIS, it was assumed that new facilities would be constructed for storage.
Storage as depleted uranium oxide could potentially result in adverse impacts to air, water, and soil quality as a result of construction activities—similar to the impacts expected for construction of any facility of a similar size. Potential air quality impacts would be from particulate matter generated during construction; such impacts could be controlled by good construction practices. Also, construction activities have the potential to result in surface water, groundwater, or soil contamination through spills of construction chemicals. However, by following good engineering practices, concentrations in soil and wastewater (and therefore surface water and groundwater) could be kept well within applicable standards or guidelines.
Long-term storage as depleted uranium oxide could require excavation of large quantities of soil and rock, if subsurface storage was selected as the preferred option. Impacts from the excavated materials could be mitigated by contouring and reseeding, or by trucking the excavated material off-site. Additionally, long-term storage as an oxide could require a relatively large land area, ranging from 80 acres for storage as UO2 in a mine up to 260 acres for storage as U3O8 in a vault.
No other adverse environmental impacts from storage were identified in the PEIS. Socioeconomic impacts were evaluated in terms of jobs and income generated, which are considered positive impacts. Long-term storage as oxide was estimated to result in about 200 to 500 direct jobs and the generation of about $9 to $25 million in direct income per operational year.
(For more details on the environmental risks from storage, see also Section 2.4 and Appendix G of the PEIS.)