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Title: Modeling Coupled Evaporation and Seepage in Ventilated Cavities

Abstract

Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), themore » effect of evaporation on seepage was very small.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Yucca Mountain Project, Las Vegas, Nevada (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
837509
Report Number(s):
V03-0136
MOL.20040828.0220, DC41392; TRN: US0503047
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 1 Jul 2004
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; BOUNDARY LAYERS; CALIBRATION; CAVITIES; DIFFUSION; EVAPORATION; FLUCTUATIONS; HUMIDITY; MINING; RADIOACTIVE WASTES; SIMULATION; THICKNESS; VENTILATION

Citation Formats

T. Ghezzehei, R. Trautz, S. Finsterle, P. Cook, and C. Ahlers. Modeling Coupled Evaporation and Seepage in Ventilated Cavities. United States: N. p., 2004. Web. doi:10.2172/837509.
T. Ghezzehei, R. Trautz, S. Finsterle, P. Cook, & C. Ahlers. Modeling Coupled Evaporation and Seepage in Ventilated Cavities. United States. doi:10.2172/837509.
T. Ghezzehei, R. Trautz, S. Finsterle, P. Cook, and C. Ahlers. Thu . "Modeling Coupled Evaporation and Seepage in Ventilated Cavities". United States. doi:10.2172/837509. https://www.osti.gov/servlets/purl/837509.
@article{osti_837509,
title = {Modeling Coupled Evaporation and Seepage in Ventilated Cavities},
author = {T. Ghezzehei and R. Trautz and S. Finsterle and P. Cook and C. Ahlers},
abstractNote = {Cavities excavated in unsaturated geological formations are important to activities such as nuclear waste disposal and mining. Such cavities provide a unique setting for simultaneous occurrence of seepage and evaporation. Previously, inverse numerical modeling of field liquid-release tests and associated seepage into cavities were used to provide seepage-related large-scale formation properties by ignoring the impact of evaporation. The applicability of such models was limited to the narrow range of ventilation conditions under which the models were calibrated. The objective of this study was to alleviate this limitation by incorporating evaporation into the seepage models. We modeled evaporation as an isothermal vapor diffusion process. The semi-physical model accounts for the relative humidity, temperature, and ventilation conditions of the cavities. The evaporation boundary layer thickness (BLT) over which diffusion occurs was estimated by calibration against free-water evaporation data collected inside the experimental cavities. The estimated values of BLT were 5 to 7 mm for the open underground drifts and 20 mm for niches closed off by bulkheads. Compared to previous models that neglected the effect of evaporation, this new approach showed significant improvement in capturing seepage fluctuations into open cavities of low relative humidity. At high relative-humidity values (greater than 85%), the effect of evaporation on seepage was very small.},
doi = {10.2172/837509},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 01 00:00:00 EDT 2004},
month = {Thu Jul 01 00:00:00 EDT 2004}
}

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