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Title: Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico

Abstract

Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ({approx}10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that {sup 230}Th/{sup 238}U activity ratios range from 0.005-0.48 and {sup 226}Ra/{sup 238}U activity ratios range from 0.006-113. {sup 239}Pu/{sup 238}U mass ratios for the saturated zone are <2 x 10{sup -14}, and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order {sup 238}U{approx}{sup 226}Ra > {sup 230}Th{approx}{sup 239}Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based onmore » U-series data from fractures and seepage water near the deposit.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Earth Sciences Division
OSTI Identifier:
982912
Report Number(s):
LBNL-3119E
Journal ID: ISSN 0013-936X; ESTHAG; TRN: US1004328
DOE Contract Number:  
DE-AC02-05CH11231
Resource Type:
Journal Article
Journal Name:
Environmental Science and Technology
Additional Journal Information:
Related Information: Journal Publication Date: 2010; Journal ID: ISSN 0013-936X
Country of Publication:
United States
Language:
English
Subject:
54; 58; DISSOLUTION; FRACTURES; MEXICO; RADIOACTIVE WASTES; RADIOISOTOPES; RADIUM; RADON; SPACE DEPENDENCE; THORIUM; TRANSPORT; TUFF; URANIUM; URANIUM DEPOSITS; URANIUM ORES; WATER; GROUND WATER

Citation Formats

Goldstein, S J, Abdel-Fattah, A I, Murrell, M T, Dobson, P F, Norman, D E, Amato, R S, and Nunn, A J. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico. United States: N. p., 2009. Web.
Goldstein, S J, Abdel-Fattah, A I, Murrell, M T, Dobson, P F, Norman, D E, Amato, R S, & Nunn, A J. Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico. United States.
Goldstein, S J, Abdel-Fattah, A I, Murrell, M T, Dobson, P F, Norman, D E, Amato, R S, and Nunn, A J. Thu . "Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico". United States. https://www.osti.gov/servlets/purl/982912.
@article{osti_982912,
title = {Uranium-series constraints on radionuclide transport and groundwater flow at the Nopal I uranium deposit, Sierra Pena Blanca, Mexico},
author = {Goldstein, S J and Abdel-Fattah, A I and Murrell, M T and Dobson, P F and Norman, D E and Amato, R S and Nunn, A J},
abstractNote = {Uranium-series data for groundwater samples from the Nopal I uranium ore deposit were obtained to place constraints on radionuclide transport and hydrologic processes for a nuclear waste repository located in fractured, unsaturated volcanic tuff. Decreasing uranium concentrations for wells drilled in 2003 are consistent with a simple physical mixing model that indicates that groundwater velocities are low ({approx}10 m/y). Uranium isotopic constraints, well productivities, and radon systematics also suggest limited groundwater mixing and slow flow in the saturated zone. Uranium isotopic systematics for seepage water collected in the mine adit show a spatial dependence which is consistent with longer water-rock interaction times and higher uranium dissolution inputs at the front adit where the deposit is located. Uranium-series disequilibria measurements for mostly unsaturated zone samples indicate that {sup 230}Th/{sup 238}U activity ratios range from 0.005-0.48 and {sup 226}Ra/{sup 238}U activity ratios range from 0.006-113. {sup 239}Pu/{sup 238}U mass ratios for the saturated zone are <2 x 10{sup -14}, and Pu mobility in the saturated zone is >1000 times lower than the U mobility. Saturated zone mobility decreases in the order {sup 238}U{approx}{sup 226}Ra > {sup 230}Th{approx}{sup 239}Pu. Radium and thorium appear to have higher mobility in the unsaturated zone based on U-series data from fractures and seepage water near the deposit.},
doi = {},
journal = {Environmental Science and Technology},
issn = {0013-936X},
number = ,
volume = ,
place = {United States},
year = {2009},
month = {10}
}