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Title: Kinetic Controls on the Desorption/Dissolution of Sorbed U(VI) and their Influence on Reactive Transport

Abstract

A number of published studies have sought to understand geochemical kinetic process of uranium (U) that are relevant to nuclear waste sites and repositories by studying the weathering of U ore bodies and downgradient transport of weathering products. Such studies have provided important insights on processes operative over many thousand to millions of years. This project also seeks knowledge on the geochemical kinetics of U, but for shorter in-ground time periods (e.g., 20-50 years) relevant to DOE legacy waste sites. Several representative field sites were selected for intense study at Hanford as part of EMSP research to provide: (1) fundamental insights on intermediate duration geochemical events of U controlling fate and transport, and (2) key scientific information needed for remedial action assessment and informed decision making. The site discussed in this poster is the 300 A uranium plume. This plume is located at the south end of Hanford and discharges directly to the Columbia River. The plume resulted from the discharge of fuels fabrication wastes (nitric acid solutions containing U and Cu) and cladding dissolution wastes (basic sodium aluminate) to the North and South Process Ponds between 1943 and 1975 near the Columbia River. A Kd-based remedial action assessment fifteenmore » years ago predicted that the plume would dissipate to concentrations below the DWS within 10 y. As a result of this assessment, an interim, MNA remedial decision was agreed to by DOE and state/federal regulators. It has been 15 y since the above assessment, and groundwater concentrations have not decreased (attenuated) as projected. Stakeholders are now demanding remedial intervention, and DOE seeks science-based conceptual and numeric models for more accurate future projections. The objectives are: (1) Identify the chemical speciation (e.g., adsorption complexes precipitates), mineral residence, and physical location of contaminant U in a depth sequence of sediments from the disposal source to groundwater. (2) Measure desorption/dissolution rates of sorbed U(VI), quantify controlling factors, and develop descriptive kinetic models to provide a scientific basis to forecast U(VI) fluxes to groundwater, future plume dynamics, and long-term contaminant attenuation. (3) Establish reaction networks and determine geochemically/ physically realistic reaction parameters to drive state-of-the-art reactive transport modeling of U in vadose zone pore fluids and groundwater.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
894676
Report Number(s):
CONF-ERSP2006-50
TRN: US0700230
Resource Type:
Conference
Resource Relation:
Conference: Annual Environmental Remediation Sciences Program PI Meeting, April 3-5, 2006, Warrenton, VA
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 54 ENVIRONMENTAL SCIENCES; 59 BASIC BIOLOGICAL SCIENCES; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; ADSORPTION; ATTENUATION; COLUMBIA RIVER; DECISION MAKING; DISSOLUTION; FABRICATION; KINETICS; PLUMES; PONDS; RADIOACTIVE WASTES; REMEDIAL ACTION; SEDIMENTS; SIMULATION; SODIUM; TRANSPORT; URANIUM; WASTES; WEATHERING

Citation Formats

Zachara, John M., Chongxuan Liu, Qafoku, Nikolla P., McKinley, James P., Catalano, Jeffrey G., Brown, Gordon E., Jr., and Davis, James A. Kinetic Controls on the Desorption/Dissolution of Sorbed U(VI) and their Influence on Reactive Transport. United States: N. p., 2006. Web.
Zachara, John M., Chongxuan Liu, Qafoku, Nikolla P., McKinley, James P., Catalano, Jeffrey G., Brown, Gordon E., Jr., & Davis, James A. Kinetic Controls on the Desorption/Dissolution of Sorbed U(VI) and their Influence on Reactive Transport. United States.
Zachara, John M., Chongxuan Liu, Qafoku, Nikolla P., McKinley, James P., Catalano, Jeffrey G., Brown, Gordon E., Jr., and Davis, James A. Wed . "Kinetic Controls on the Desorption/Dissolution of Sorbed U(VI) and their Influence on Reactive Transport". United States. doi:. https://www.osti.gov/servlets/purl/894676.
@article{osti_894676,
title = {Kinetic Controls on the Desorption/Dissolution of Sorbed U(VI) and their Influence on Reactive Transport},
author = {Zachara, John M. and Chongxuan Liu and Qafoku, Nikolla P. and McKinley, James P. and Catalano, Jeffrey G. and Brown, Gordon E., Jr. and Davis, James A.},
abstractNote = {A number of published studies have sought to understand geochemical kinetic process of uranium (U) that are relevant to nuclear waste sites and repositories by studying the weathering of U ore bodies and downgradient transport of weathering products. Such studies have provided important insights on processes operative over many thousand to millions of years. This project also seeks knowledge on the geochemical kinetics of U, but for shorter in-ground time periods (e.g., 20-50 years) relevant to DOE legacy waste sites. Several representative field sites were selected for intense study at Hanford as part of EMSP research to provide: (1) fundamental insights on intermediate duration geochemical events of U controlling fate and transport, and (2) key scientific information needed for remedial action assessment and informed decision making. The site discussed in this poster is the 300 A uranium plume. This plume is located at the south end of Hanford and discharges directly to the Columbia River. The plume resulted from the discharge of fuels fabrication wastes (nitric acid solutions containing U and Cu) and cladding dissolution wastes (basic sodium aluminate) to the North and South Process Ponds between 1943 and 1975 near the Columbia River. A Kd-based remedial action assessment fifteen years ago predicted that the plume would dissipate to concentrations below the DWS within 10 y. As a result of this assessment, an interim, MNA remedial decision was agreed to by DOE and state/federal regulators. It has been 15 y since the above assessment, and groundwater concentrations have not decreased (attenuated) as projected. Stakeholders are now demanding remedial intervention, and DOE seeks science-based conceptual and numeric models for more accurate future projections. The objectives are: (1) Identify the chemical speciation (e.g., adsorption complexes precipitates), mineral residence, and physical location of contaminant U in a depth sequence of sediments from the disposal source to groundwater. (2) Measure desorption/dissolution rates of sorbed U(VI), quantify controlling factors, and develop descriptive kinetic models to provide a scientific basis to forecast U(VI) fluxes to groundwater, future plume dynamics, and long-term contaminant attenuation. (3) Establish reaction networks and determine geochemically/ physically realistic reaction parameters to drive state-of-the-art reactive transport modeling of U in vadose zone pore fluids and groundwater.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Apr 05 00:00:00 EDT 2006},
month = {Wed Apr 05 00:00:00 EDT 2006}
}

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