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Title: Deployment of an Alternative Closure Cover and Monitoring System at the Mixed Waste Disposal Unit U-3ax/bl at the Nevada Test Site

Abstract

In October 2000, final closure was initiated of U-3ax/bl, a mixed waste disposal unit at the Nevada Test Site (NTS). The application of approximately 30 cm of topsoil, composed of compacted native alluvium onto an operational cover, seeding of the topsoil, installation of soil water content sensors within the cover, and deployment of a drainage lysimeter facility immediately adjacent to the disposal unit initiated closure. This closure is unique in that it required the involvement of several U.S. Department of Energy (DOE) Environmental Management (EM) groups: Waste Management (WM), Environmental Restoration (ER), and Technology Development (TD). Initial site characterization of the disposal unit was conducted by WM. Regulatory approval for closure of the disposal unit was obtained by ER, closure of the disposal unit was conducted by ER, and deployment of the drainage lysimeter facility was conducted by WM and ER, with funding provided by the Accelerated Site Technology Deployment ( ASTD) program, administered under TD. In addition, this closure is unique in that a monolayer closure cover, also known as an evapotranspiration (ET) cover, consisting of native alluvium, received regulatory approval instead of a traditional Resource Conservation and Recovery Act (RCRA) multi-layered cover. Recent studies indicate that in themore » arid southwestern United States, monolayer covers may be more effective at isolating waste than layered covers because of the tendency of clay layers to desiccate and crack, and subsequently develop preferential pathways. The lysimeter facility deployed immediately adjacent to the closure cover consists of eight drainage lysimeters with three surface treatments: two were left bare; two were revegetated with native species; two were allowed to revegetate with invader species; and two are reserved for future studies. The lysimeters are constructed such that any drainage through the bottoms of the lysimeters can be measured. Sensors installed in the closure cover provide soil water content data, whereas sensors installed in the lysimeters provide soil water content, soil water potential, soil temperature, and drainage data for a detailed evaluation of the cover performance. Revegetation establishes a stable plant community that maximizes water loss through transpiration and reduces water and wind erosion and ultimately restores the disposal unit to its surrounding Great Basin Desert environment.« less

Authors:
;
Publication Date:
Research Org.:
Bechtel Nevada Corp. (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
774295
Report Number(s):
DOE/NV/11718-462
TRN: US0100896
DOE Contract Number:  
AC08-96NV11718
Resource Type:
Conference
Resource Relation:
Conference: Waste Management '01 Conference, Tucson, AZ (US), 02/25/2001--03/01/2001; Other Information: PBD: 1 Feb 2001
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; MONITORING; NEVADA TEST SITE; RADIOACTIVE WASTE DISPOSAL; RADIOACTIVE WASTE FACILITIES; HAZARDOUS MATERIALS; RADIOACTIVE WASTES; COVERINGS; LYSIMETERS; REMEDIAL ACTION

Citation Formats

Levitt, D G, and Fitzmaurice, T M. Deployment of an Alternative Closure Cover and Monitoring System at the Mixed Waste Disposal Unit U-3ax/bl at the Nevada Test Site. United States: N. p., 2001. Web.
Levitt, D G, & Fitzmaurice, T M. Deployment of an Alternative Closure Cover and Monitoring System at the Mixed Waste Disposal Unit U-3ax/bl at the Nevada Test Site. United States.
Levitt, D G, and Fitzmaurice, T M. 2001. "Deployment of an Alternative Closure Cover and Monitoring System at the Mixed Waste Disposal Unit U-3ax/bl at the Nevada Test Site". United States. https://www.osti.gov/servlets/purl/774295.
@article{osti_774295,
title = {Deployment of an Alternative Closure Cover and Monitoring System at the Mixed Waste Disposal Unit U-3ax/bl at the Nevada Test Site},
author = {Levitt, D G and Fitzmaurice, T M},
abstractNote = {In October 2000, final closure was initiated of U-3ax/bl, a mixed waste disposal unit at the Nevada Test Site (NTS). The application of approximately 30 cm of topsoil, composed of compacted native alluvium onto an operational cover, seeding of the topsoil, installation of soil water content sensors within the cover, and deployment of a drainage lysimeter facility immediately adjacent to the disposal unit initiated closure. This closure is unique in that it required the involvement of several U.S. Department of Energy (DOE) Environmental Management (EM) groups: Waste Management (WM), Environmental Restoration (ER), and Technology Development (TD). Initial site characterization of the disposal unit was conducted by WM. Regulatory approval for closure of the disposal unit was obtained by ER, closure of the disposal unit was conducted by ER, and deployment of the drainage lysimeter facility was conducted by WM and ER, with funding provided by the Accelerated Site Technology Deployment ( ASTD) program, administered under TD. In addition, this closure is unique in that a monolayer closure cover, also known as an evapotranspiration (ET) cover, consisting of native alluvium, received regulatory approval instead of a traditional Resource Conservation and Recovery Act (RCRA) multi-layered cover. Recent studies indicate that in the arid southwestern United States, monolayer covers may be more effective at isolating waste than layered covers because of the tendency of clay layers to desiccate and crack, and subsequently develop preferential pathways. The lysimeter facility deployed immediately adjacent to the closure cover consists of eight drainage lysimeters with three surface treatments: two were left bare; two were revegetated with native species; two were allowed to revegetate with invader species; and two are reserved for future studies. The lysimeters are constructed such that any drainage through the bottoms of the lysimeters can be measured. Sensors installed in the closure cover provide soil water content data, whereas sensors installed in the lysimeters provide soil water content, soil water potential, soil temperature, and drainage data for a detailed evaluation of the cover performance. Revegetation establishes a stable plant community that maximizes water loss through transpiration and reduces water and wind erosion and ultimately restores the disposal unit to its surrounding Great Basin Desert environment.},
doi = {},
url = {https://www.osti.gov/biblio/774295}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 2001},
month = {Thu Feb 01 00:00:00 EST 2001}
}

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