Reactive transport of uranium in fractured crystalline rock: Upscaling in time and distance
Abstract
In this study, batch adsorption and breakthrough column experiments were conducted to evaluate uranium transport through altered material that fills fractures in a granite rock system at the Grimsel Test Site in Switzerland at pH 6.9 and 7.9. The role of adsorption and desorption kinetics was evaluated with reactive transport modeling by comparing one-, two-, and three-site models. Emphasis was placed on describing long desorption tails that are important for upscaling in time and distance. The effect of increasing pH in injection solutions was also evaluated. For pH 6.9, a three-site model with forward rate constants between 0.07 and 0.8 ml g–1 h–1, reverse rate constants between 0.001 and 0.06 h–1, and site densities of 1.3, 0.104, and 0.026 μmol g–1 for ‘weak/fast’, ‘strong/slow’, and ‘very strong/very slow’ sites provided the best fits. For pH 7.9, a three-site model with forward rate constants between 0.05 and 0.8 mL g–1 h–1, reverse rate constants between 0.001 and 0.6 h–1, and site densities of 1.3, 0.039, and 0.013 μmol g–1 for a ‘weak/fast’, ‘strong/slow’, and ‘very strong/very slow’ sites provided the best fits. Column retardation coefficients (Rd) were 80 for pH 6.9 and 10.3 for pH 7.9. Model parameters determined from themore »
- Publication Date:
- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1246914
- Alternate Identifier(s):
- OSTI ID: 1396753
- Report Number(s):
- LA-UR-15-25174
Journal ID: ISSN 0301-4797; PII: S0301479715302668
- Grant/Contract Number:
- AC52-06NA25396
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of Environmental Management
- Additional Journal Information:
- Journal Volume: 165; Journal Issue: C; Journal ID: ISSN 0301-4797
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES; 12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; uranium; Grimsel granodiorite; reactive transport modeling; sorption kinetics; rate coefficients; column experiments
Citation Formats
Dittrich, Timothy M., and Reimus, Paul W. Reactive transport of uranium in fractured crystalline rock: Upscaling in time and distance. United States: N. p., 2015.
Web. doi:10.1016/j.jenvman.2015.09.014.
Dittrich, Timothy M., & Reimus, Paul W. Reactive transport of uranium in fractured crystalline rock: Upscaling in time and distance. United States. https://doi.org/10.1016/j.jenvman.2015.09.014
Dittrich, Timothy M., and Reimus, Paul W. Tue .
"Reactive transport of uranium in fractured crystalline rock: Upscaling in time and distance". United States. https://doi.org/10.1016/j.jenvman.2015.09.014. https://www.osti.gov/servlets/purl/1246914.
@article{osti_1246914,
title = {Reactive transport of uranium in fractured crystalline rock: Upscaling in time and distance},
author = {Dittrich, Timothy M. and Reimus, Paul W.},
abstractNote = {In this study, batch adsorption and breakthrough column experiments were conducted to evaluate uranium transport through altered material that fills fractures in a granite rock system at the Grimsel Test Site in Switzerland at pH 6.9 and 7.9. The role of adsorption and desorption kinetics was evaluated with reactive transport modeling by comparing one-, two-, and three-site models. Emphasis was placed on describing long desorption tails that are important for upscaling in time and distance. The effect of increasing pH in injection solutions was also evaluated. For pH 6.9, a three-site model with forward rate constants between 0.07 and 0.8 ml g–1 h–1, reverse rate constants between 0.001 and 0.06 h–1, and site densities of 1.3, 0.104, and 0.026 μmol g–1 for ‘weak/fast’, ‘strong/slow’, and ‘very strong/very slow’ sites provided the best fits. For pH 7.9, a three-site model with forward rate constants between 0.05 and 0.8 mL g–1 h–1, reverse rate constants between 0.001 and 0.6 h–1, and site densities of 1.3, 0.039, and 0.013 μmol g–1 for a ‘weak/fast’, ‘strong/slow’, and ‘very strong/very slow’ sites provided the best fits. Column retardation coefficients (Rd) were 80 for pH 6.9 and 10.3 for pH 7.9. Model parameters determined from the batch and column experiments were used in 50 year large-scale simulations for continuous and pulse injections and indicated that a three-site model is necessary at pH 6.9, although a Kd-type equilibrium partition model with one-site was adequate for large scale predictions at pH 7.9. Batch experiments were useful for predicting early breakthrough times in the columns while column experiments helped differentiate the relative importance of sorption sites and desorption rate constants on transport.},
doi = {10.1016/j.jenvman.2015.09.014},
journal = {Journal of Environmental Management},
number = C,
volume = 165,
place = {United States},
year = {Tue Sep 29 00:00:00 EDT 2015},
month = {Tue Sep 29 00:00:00 EDT 2015}
}
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