Award Date


Degree Type


Degree Name

Master of Science (MS)

First Committee Member

Zhongbo Yu

Number of Pages



Yucca Mountain, Nevada has been selected as a potential high-level nuclear waste repository. The groundwater system at Yucca Mountain is a primary medium through which radionuclides might move away from the potential repository. Characterization studies have identified 237Np, 235 U and 239Pu as radionuclides of concern. In this study, simulations of solid solubility, solution speciation, and transport of selected radionuclides are conducted with PHREEQC, a geochemical modeling system. Results from solubility and speciation simulations indicate the influence of pH value and CO2 fugacity on radionuclide dissolution and aqueous species in solution. Kinetic transport simulations produced radionuclide breakthrough curves under various conditions including sorption/no sorption, different flow velocities, and mixing of two types of groundwater. Results from transport modeling indicate that sorption activity makes a significant contribution to the retardation of solute transport whereas flow velocity controls the contact time between solutions and sediments which has different effects on the sorption activity.


Geochemical; Modeling; Mountain; Radionuclides; Selected; Transport; Yucca

Controlled Subject

Hydrology; Geochemistry

File Format


File Size

2.71 MB

Degree Grantor

University of Nevada, Las Vegas




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