The long-term disposal of commercially generated high-level wastes (HLW) is of principal importance for the public safety because these wastes can be released to the environment and reach the biosphere. One solution for the isolation of the wastes is to put them into deep geologic repository. One way to predict the fate of the released radioactive species from deep geologic repository is to use a mathematical model. The mathematical model can be used to predict the transport in space and time of the radioactive species. Using as input parameters the characteristics for a specific place we can decide if a place can be used as a repository. We can cite here the "Yucca Mountain Site" in Nye County, Nevada, which is currently planned to be a HLW repository. We developed a three dimensional model of subsurface flow and reactive chemical transport. The second order partial differential equations governing the groundwater flow in saturated and unsaturated zones, and the advection-diffusion equation for the transport of solute are solved using the finite element method (FEM). The chemical phenomena are treated using the concept of point chemical equilibrium at each point of the mesh used in the finite element scheme. The Newton-Raphson method is employed to calculate the chemical equilibrium. The solute transport equation and the point chemical equilibrium are solved simultaneously using an iterative scheme. Radioactive decay is included in the solute transport equation and the chemical species phenomena of complexation, surface adsorption, ion-exchange, oxidation-reduction and precipitation are included in the point chemical equilibrium.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/280127 |
| Date | January 2002 |
| Creators | Diaz-Martinez, Jose |
| Contributors | Wacks, Morton E., Ganapol, Barry D. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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