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Title: Variation of permeability with temperature in fractured Topopah Spring tuff samples

Abstract

Fractures will play an important role in the near-field hydrology of a nuclear-waste package in a mined repository. Our previous studies showed that the water permeability of fractured Topopah Springs tuff samples decreased by more than three orders of magnitude when the sample`s temperature (in the case of a sample under a thermal gradient, the temperature in the hot zone) increased to 150{degree}C at a constant confining pressure of 5 MPa. When the fractured tuff samples were returned to room temperature the water permeability did not recover. We attributed the permeability decrease to smoothing of the asperities on the fracture surfaces, which was caused by the dissolution and redeposition of silica minerals as water flowed through the sample. Water permeability of an intact tuff sample did not change significantly under similar experimental conditions. In this study, a fractured Topopah Spring tuff sample was used to determine the variation of nitrogen (N{sub 2}) permeability with increasing temperature at a constant confining pressure of 5 MPa under the following conditions: dry sample, sample saturated with standing water, and steam flowing through the sample. The N{sub 2} permeability of a dry fractured tuff sample was independent of temperature. The water permeability measured atmore » room temperature before and after the sample was heated to 150{degree}C with standing water did not change either. On the other hand, flowing steam through the sample at 127{degree}C for about one week decreased the N{sub 2} permeability by more than one order of magnitude. Apparently flowing steam and flowing water have a similar effect on smoothing the asperities of the fracture surfaces. 8 refs., 4 figs., 1 tab.« less

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
138000
Report Number(s):
UCRL-JC-104765; CONF-910435-16
ON: DE91005186; TRN: 91:004778
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: 2. annual American Nuclear Society (ANS) international high level radioactive waste management conference, Las Vegas, NV (United States), 28 Apr - 3 May 1991; Other Information: PBD: Nov 1990
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; 54 ENVIRONMENTAL SCIENCES; TUFF; PERMEABILITY; WATER; NITROGEN; HIGH-LEVEL RADIOACTIVE WASTES; WASTE-ROCK INTERACTIONS; RADIOACTIVE WASTE MANAGEMENT; ROCK-FLUID INTERACTIONS; TEMPERATURE DEPENDENCE; FRACTURES; YUCCA MOUNTAIN; HYDROLOGY; FLUID MECHANICS; HYDRAULICS; FLUID FLOW; GEOLOGIC FRACTURES; Yucca Mountain Project

Citation Formats

Lin, Wunan. Variation of permeability with temperature in fractured Topopah Spring tuff samples. United States: N. p., 1990. Web.
Lin, Wunan. Variation of permeability with temperature in fractured Topopah Spring tuff samples. United States.
Lin, Wunan. 1990. "Variation of permeability with temperature in fractured Topopah Spring tuff samples". United States. https://www.osti.gov/servlets/purl/138000.
@article{osti_138000,
title = {Variation of permeability with temperature in fractured Topopah Spring tuff samples},
author = {Lin, Wunan},
abstractNote = {Fractures will play an important role in the near-field hydrology of a nuclear-waste package in a mined repository. Our previous studies showed that the water permeability of fractured Topopah Springs tuff samples decreased by more than three orders of magnitude when the sample`s temperature (in the case of a sample under a thermal gradient, the temperature in the hot zone) increased to 150{degree}C at a constant confining pressure of 5 MPa. When the fractured tuff samples were returned to room temperature the water permeability did not recover. We attributed the permeability decrease to smoothing of the asperities on the fracture surfaces, which was caused by the dissolution and redeposition of silica minerals as water flowed through the sample. Water permeability of an intact tuff sample did not change significantly under similar experimental conditions. In this study, a fractured Topopah Spring tuff sample was used to determine the variation of nitrogen (N{sub 2}) permeability with increasing temperature at a constant confining pressure of 5 MPa under the following conditions: dry sample, sample saturated with standing water, and steam flowing through the sample. The N{sub 2} permeability of a dry fractured tuff sample was independent of temperature. The water permeability measured at room temperature before and after the sample was heated to 150{degree}C with standing water did not change either. On the other hand, flowing steam through the sample at 127{degree}C for about one week decreased the N{sub 2} permeability by more than one order of magnitude. Apparently flowing steam and flowing water have a similar effect on smoothing the asperities of the fracture surfaces. 8 refs., 4 figs., 1 tab.},
doi = {},
url = {https://www.osti.gov/biblio/138000}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Nov 01 00:00:00 EST 1990},
month = {Thu Nov 01 00:00:00 EST 1990}
}

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