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Title: Impacts of reducing conditions in the saturated zone at Yucca Mountain.

Abstract

No abstract prepared.

Authors:
 [1]; ; ; ;  [2];  [3];  [1];  [4];
  1. (Los Alamos National laboratory, Los Alamos, NM)
  2. (RHYM, LLC, Albuquerque, NM)
  3. (Bechtel/SAIC, Las Vegas, NV)
  4. (GCX, Tucson, AZ)
Publication Date:
Research Org.:
Sandia National Laboratories
Sponsoring Org.:
USDOE
OSTI Identifier:
901719
Report Number(s):
SAND2006-0705C
TRN: US0702642
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the International High-Level Radioactive Waste Conference held April 30 - May 4, 2006 in Las Vegas, NV.
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 58 GEOSCIENCES; HIGH-LEVEL RADIOACTIVE WASTES; YUCCA MOUNTAIN; GEOCHEMISTRY; SATURATION

Citation Formats

Kelkar, Sharad, James, Scott Carlton, Kuzio, Stephanie Pauline, Arnold, Bill Walter, Kalinina, Elena Arkadievna, Zhu, Ming, Robinson, Bruce A., Meijer, Arend, and JovÔe-ColÔon, Carlos F. Impacts of reducing conditions in the saturated zone at Yucca Mountain.. United States: N. p., 2006. Web.
Kelkar, Sharad, James, Scott Carlton, Kuzio, Stephanie Pauline, Arnold, Bill Walter, Kalinina, Elena Arkadievna, Zhu, Ming, Robinson, Bruce A., Meijer, Arend, & JovÔe-ColÔon, Carlos F. Impacts of reducing conditions in the saturated zone at Yucca Mountain.. United States.
Kelkar, Sharad, James, Scott Carlton, Kuzio, Stephanie Pauline, Arnold, Bill Walter, Kalinina, Elena Arkadievna, Zhu, Ming, Robinson, Bruce A., Meijer, Arend, and JovÔe-ColÔon, Carlos F. Sun . "Impacts of reducing conditions in the saturated zone at Yucca Mountain.". United States. doi:.
@article{osti_901719,
title = {Impacts of reducing conditions in the saturated zone at Yucca Mountain.},
author = {Kelkar, Sharad and James, Scott Carlton and Kuzio, Stephanie Pauline and Arnold, Bill Walter and Kalinina, Elena Arkadievna and Zhu, Ming and Robinson, Bruce A. and Meijer, Arend and JovÔe-ColÔon, Carlos F.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Conference:
Other availability
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  • Variations in groundwater redox chemistry in the saturated zone near Yucca Mountain could have significant repository to the accessible environment. This study examines geochemical data relevant to the distribution of redox impacts on processes associated with the potential transport of redox-sensitive radionuclides from the proposed conditions in the saturated zone, the relationships between redox state and solubility and sorption coefficients for technetium and neptunium, and sensitivity in transport model simulations. Results indicate evidence for a zone of reducing conditions in the volcanic rocks of the saturated zone located to the east and south of the repository and along the inferredmore » flow paths from the repository. A working hypothesis is that these reducing conditions are related to the presence of minor pyrite in the matrix of some volcanic units. Chemical equilibrium modeling of technetium solubility using EQ3/6 software codes is used to estimate the value of solubility limits as a function of Eh. Surface complexation modeling with the EQ3 code is used to estimate neptunium sorption coefficient values as a function of Eh. A general analytical approach, one-dimensional reactive transport modeling, and the three-dimensional saturated zone site-scale transport model using the FEHM software code are used to evaluate the impacts of solubility limits and enhanced sorption in reducing zones on the simulated transport of technetium and neptunium in the saturated zone. Results show that if precipitation occurs in response to flow through a reducing zone, then the peak concentration released to the accessible environment will be restricted to the solubility limit. Simulations also show that enhanced sorption within a reducing zone of modest width leads to significantly greater retardation of radionuclides in the saturated zone.« less
  • A qualitative three-dimensional analysis of the saturated zone flow system was performed for a 8 km {times} 8 km region including the potential Yucca Mountain repository site. Certain recognized geologic features of unknown hydraulic properties were introduced to assess the general response of the flow field to these features. Two of these features, the Solitario Canyon fault and the proposed fault in Drill Hole Wash, appear to constrain flow and allow calibration.
  • A qualitative three-dimensional analysis of the saturated zone flow system was performed for a 8 km {times} 8 km region including the potential Yucca Mountain repository site. Certain recognized geologic features of unknown hydraulic properties were introduced to assess the general response of the flow field to these features. Two of these features, the Solitario Canyon fault and the proposed fault in Drill Hole Wash, appear to constrain flow and allow calibration.
  • This paper presents preliminary results of groundwater modeling of the saturated zone in the vicinity of Yucca Mountain. The analysis used both a regional (approximately 250 {times} 250 km) and subregional (50 {times} 50 km) finite difference model. Numerical simulations were conducted to determine the impact of various disruptive conditions that might take place over the life span of a potential repository located beneath Yucca Mountain on the saturated groundwater flow field, as well as changes in the watertable elevations. These conditions included increases in precipitation and groundwater recharge within the regional model, changes in permeability of existing hydrogeologic barriers,more » and the vertical intrusion of volcanic dikes at various orientations through the saturated zone. Based on the regional analysis, the rise in the water-table in the vicinity of Yucca Mountain due to various postulated conditions ranged from only a few meters to over 200 m in certain cases. The increase in evapotranspiration and surface runoff as the water table rises was neglected in this analysis. Results of the subregional model analysis, which was used to simulate intrusive dikes approximately 4 km in length in the vicinity of Yucca Mountain, showed water-table rises ranging from a few meters to as much as 103 m. Dikes oriented approximately north-south beneath Yucca Mountain produced the highest water-table rises. Some of the results from both the regional and subregional analysis are presented in this paper. A more complete discussion of the results and details of the analysis is given in a recent report by Ahola and Sagar.« less
  • Development of a preliminary three-dimensional model of the saturated zone at Yucca Mountain, the potential location for a high-level nuclear waste repository, is presented. The development of the model advances the technology of interfacing: (1)complex three-dimensional hydrogeologic framework modeling; (2) fully three-dimensional, unstructured, finite-element mesh generation; and (3) groundwater flow, heat, and transport simulation. The three-dimensional hydrogeologic framework model is developed using maps, cross sections, and well data. The framework model data are used to feed an automated mesh generator, designed to discretize irregular three-dimensional solids,a nd to assign materials properties from the hydrogeologic framework model to the tetrahedral elements.more » The mesh generator facilitated the addition of nodes to the finite-element mesh which correspond to the exact three-dimensional position of the potentiometric surface based on water-levels from wells. A ground water flow and heat simulator is run with the resulting finite- element mesh, within a parameter-estimation program. The application of the parameter-estimation program is designed to provide optimal values of permeability and specified fluxes over the model domain to minimize the residual between observed and simulated water levels.« less