HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Mayers, C. J. Articles by Michel, R. L. Search for Related Content PubMed Articles by Mayers, C. J. Articles by Michel, R. L. GeoRef GeoRef Citation Agricola Articles by Mayers, C. J. Articles by Michel, R. L. Related Collections Radionuclides Solute Transport Models

Modeling Tritium Transport Through a Deep Unsaturated Zone in an Arid Environment

^a U.S. Geological Survey, WRD, 333 West Nye Lane, Carson City, NV 89706
^b Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512
^c Dep. of Geological Sciences, Univ. of Nevada, Reno, NV 89557
^d U.S. Geological Survey, WRD, NRP, 345 Middlefield Road, Menlo Park, CA 94025

View larger version (35K): [in a new window]   Fig. 1. Location map showing the Amargosa Desert Research Site (ADRS) and the low-level radioactive waste (LLRW) facility near Beatty, NV.

View larger version (25K): [in a new window]   Fig. 2. Low-level radioactive waste facility, chemical waste facility, and deep unsaturated zone boreholes.

View larger version (24K): [in a new window]   Fig. 3. Plan view of conceptualized source trench and 600-m transect, A–A'.

View larger version (33K): [in a new window]   Fig. 4. (a) Computational grid and (b) lithology of modeled vertical slice along A–A' transect shown in Fig. 3. Locations of unsaturated zone boreholes UZB-2 and UZB-3 are included for reference (see Fig. 3).

View larger version (32K): [in a new window]   Fig. 5. Simulated steady state temperature, gas phase pressure, and water content profiles.

View larger version (28K): [in a new window]   Fig. 6. (a) Water content at boreholes UZB-1, UZB-2, and UZB-3. Concentration profiles of tritiated water vapor (3HHOg) in units of Bq kg–1 of water in the gas phase at (b) UZB-3 borehole and (c) UZB-2 borehole for selected years (1994 data from Prudic and Striegl, 1995; 1998 data from Prudic et al., 1999).

View larger version (23K): [in a new window]   Fig. 7. Simulated tritiated water vapor (3HHOg) concentrations in units of Bq kg–1 of water in the gas phase for the reference model simulation at time = 40 yr. Simulated 3HHOg concentration of 1 Bq kg–1 migrated to a maximum horizontal extent (MHE) of 27 m from the vertical face of the source trench and a maximum vertical extent (MVE) of 18 m from the bottom of the source trench.

View larger version (17K): [in a new window]   Fig. 8. Summary of simulated tritium (3H) transport as tritiated water vapor (3HHOg) in units of Bq kg–1 showing the effects of source temperature (TS), source-pressure difference above ambient (PS), and anisotropy on the maximum horizontal extent (MHE) from the vertical face of the source trench and the maximum vertical extent (MVE) from the bottom of the source trench at time = 40 yr. The leading edge of the plume was defined as the concentration of 3HHOg = 1 Bq kg–1 of water in the gas phase.

View larger version (24K): [in a new window]   Fig. 9. Simulated tritiated water vapor (3HHOg) concentrations in units of Bq kg–1 of water in the gas phase at time = 40 yr for (a) source temperature (TS) 45°C simulation [maximum horizontal extent (MHE) = 32 m and a maximum vertical extent (MVE) = 24 m], (b) source-pressure difference above ambient (PS) 500 Pa simulation (MHE = 40 m and MVE = 21 m), (c) TS 45°C and PS 500 Pa simulation (MHE = 42 m and MVE = 28 m), and (d) anisotropic (1:100), TS 45°C, and PS 500 Pa simulation (MHE = 121 m and MVE = 31 m). The MHE and MVE values are based on a simulated 3HHOg concentration of 1 Bq kg–1.