Organo-I Scoping Efforts/Experiments for 200-UP-1 I-129 Remedy Evaluation Using Mass Spectrometry
EMSL Project ID
49712
Abstract
Isotopes of iodine were generated during plutonium production within the nine production reactors at the U.S. Department of Energy (DOE) Hanford Site. The short half-life 131I was released from the fuel into the atmosphere during the dissolution process (when the fuel was dissolved) in the Hanford Site 200 Area, is no longer present at concentrations of concern in the environment. The long half-life 129I generated at the Hanford Site during reactor operations was 1) Stored in single-shell and double-shell tanks, 2) Discharged to liquid disposal sites (e.g., cribs and trenches), 3) Released to the atmosphere during fuel reprocessing operations, or 4) Captured by off-gas absorbent devices (silver reactors) at chemical separations plants (PUREX, B-Plant, T-Plant, and REDOX). Releases of 129I to the subsurface have resulted in several large, though dilute, plumes in the groundwater. There is also 129I remaining in the vadose zone beneath disposal or leak locations. The fate and transport of 129I in the environment and potential remediation technologies are currently being studied as part of environmental remediation activities at the Hanford Site. A conceptual model describing the nature and extent of subsurface contamination, factors that control plume behavior, and factors relevant to potential remediation processes is needed to support environmental remedy decisions. Because 129I is an uncommon contaminant, relevant remediation experience and scientific literature are limited. Thus, the conceptual model also needs to both describe known contaminant and biogeochemical process information and to identify aspects about which additional information needed to effectively support remedy decisions. Moreover, organic materials in the subsurface may interact with iodine (129I and 127I )and affect its fate and transport through 1) formation of immobile sediment-associated Organo-I compounds, 2) formation of mobile soluble Organo-I compounds, 3) formation of volatile Organo-I compounds, 4) providing electron donors for microbially mediated reduction reactions that directly or indirectly affect iodine speciation, and 5) providing adsorption capacity for iodine species. Formation of Organo-I is important because iodine forms extremely strong bonds with some organic compounds. In this proposal we seek to understand how Iodine binds to organic matter and what the controls on that are.
Project Details
Start Date
2017-02-02
End Date
2019-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)