Iodine-129 (I-129) generated at the U.S. Department of Energy Hanford Site during plutonium production was released to the subsurface, resulting in several large, dilute plumes in the groundwater, including the plume in the 200-UP-1 operable unit (OU). A requirement in the Record of Decision (ROD) for interim remedial action at the 200-UP-1 OU is to “evaluate potential treatment options for I-129 as part of the selected remedy through further technology evaluation. If one or more viable technologies are identified, treatability tests will be conducted for those technologies.” The requirements also state: “In the event a viable treatment technology is not available, the use of a technical impracticable waiver under 40 CFR 300.430(f)(l)(ii)(c) may need to be considered as part of the final remedy.” Recent work has increased the understanding of iodine behavior in the Hanford subsurface. A thorough review of potential remediation technologies has also been completed, including laboratory testing of promising technologies to evaluate their effectiveness for the iodine conditions at the 200-UP-1 OU. Using the combined information from these efforts, this report evaluates potential remediation technology options for the 200-UP-1 OU with respect to the need for conducting treatability tests and to document the technology status in support of future OU decisions for addressing the I-129 plume.
Revised: January 23, 2020 |
Published: September 30, 2019