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Title: Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes

Abstract

Solidification of low-activity wastes with cementitious materials is a widely accepted technique that contains and isolates waste from the hydrologic environment. The radionuclides I-129, Se-75, Tc-99, and U-238 are identified as long-term dose contributors. The anionic nature of these radionuclides in aqueous solutions allows them to readily leach into the subsurface environment. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages via mass flow and/or diffusion into the surrounding subsurface environment. Assessing the long-term performance of waste grouts for encasement of radionuclides requires understanding the: (1) speciation and interaction of the radionuclides within the concrete wasteform, (2) diffusion of radionuclide species when contacted with vadose zone porewater or groundwater under environmentally relevant conditions, and (3) long-term durability and weathering of concrete waste forms. An improved understanding of the interactions of long-lived radionuclides in cementitious matrices will improve predictions of the long-term fate of these sequestered contaminants. An integrated laboratory investigation has been conducted including: (1) a multifaceted spectroscopic investigation to interrogate the speciation and interaction of radionuclides within concrete wasteforms, (2) solubility tests to quantify the stability of solid phases identified as radionuclide-controlling phases, (3) quantify the diffusion of radionuclidesmore » from concrete wasteforms into surrounding subsurface sediment under realistic moisture contents (4%, 7%, and 15% by weight moisture content), (4) quantify the long-term durability of concrete waste forms as a function environmental parameters relevant to depository conditions, and (5) identify the formation of secondary phases or processes (microcracking) that influence radionuclide retention. Data obtained from this investigation provides valuable information for understanding the speciation, behavior, and fate of radionuclides immobilized within concrete wasteforms under vadose zone conditions and underscores the necessity for robust, multi-disciplinary performance assessments for concrete waste forms.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1039134
Report Number(s):
PNNL-SA-66511
830403000; TRN: US1202076
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Conference
Resource Relation:
Conference: MRS Symposium Proceedings Series: 2009 MRS Spring Meeting - Scientific Basis for Nuclear Waste Management XXXIII, May 24-29, 2009, St Petersburg, Russia, 1193:Paper No. 349
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; AQUEOUS SOLUTIONS; CONCRETES; DIFFUSION; GROUTING; MANAGEMENT; MATRICES; MOISTURE; PERFORMANCE; RADIOACTIVE WASTES; RADIOISOTOPES; RETENTION; SEDIMENTS; SOLIDIFICATION; SOLUBILITY; STABILITY; WASTE FORMS; WASTES; WATER INFLUX; WEATHERING

Citation Formats

Wellman, Dawn M, Bovaird, Chase C, Parker, Kent E, Cordova, Elsa A, Davis, Aaron M, Mattigod, Shas V, Powers, Laura, and Wood, Marcus I. Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes. United States: N. p., 2009. Web. doi:10.1557/PROC-1193-349.
Wellman, Dawn M, Bovaird, Chase C, Parker, Kent E, Cordova, Elsa A, Davis, Aaron M, Mattigod, Shas V, Powers, Laura, & Wood, Marcus I. Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes. United States. https://doi.org/10.1557/PROC-1193-349
Wellman, Dawn M, Bovaird, Chase C, Parker, Kent E, Cordova, Elsa A, Davis, Aaron M, Mattigod, Shas V, Powers, Laura, and Wood, Marcus I. 2009. "Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes". United States. https://doi.org/10.1557/PROC-1193-349.
@article{osti_1039134,
title = {Cementitious Wasteforms for Immobilization of Low-Activity Radioactive Wastes},
author = {Wellman, Dawn M and Bovaird, Chase C and Parker, Kent E and Cordova, Elsa A and Davis, Aaron M and Mattigod, Shas V and Powers, Laura and Wood, Marcus I},
abstractNote = {Solidification of low-activity wastes with cementitious materials is a widely accepted technique that contains and isolates waste from the hydrologic environment. The radionuclides I-129, Se-75, Tc-99, and U-238 are identified as long-term dose contributors. The anionic nature of these radionuclides in aqueous solutions allows them to readily leach into the subsurface environment. Any failure of concrete encasement may result in water intrusion and consequent mobilization of radionuclides from the waste packages via mass flow and/or diffusion into the surrounding subsurface environment. Assessing the long-term performance of waste grouts for encasement of radionuclides requires understanding the: (1) speciation and interaction of the radionuclides within the concrete wasteform, (2) diffusion of radionuclide species when contacted with vadose zone porewater or groundwater under environmentally relevant conditions, and (3) long-term durability and weathering of concrete waste forms. An improved understanding of the interactions of long-lived radionuclides in cementitious matrices will improve predictions of the long-term fate of these sequestered contaminants. An integrated laboratory investigation has been conducted including: (1) a multifaceted spectroscopic investigation to interrogate the speciation and interaction of radionuclides within concrete wasteforms, (2) solubility tests to quantify the stability of solid phases identified as radionuclide-controlling phases, (3) quantify the diffusion of radionuclides from concrete wasteforms into surrounding subsurface sediment under realistic moisture contents (4%, 7%, and 15% by weight moisture content), (4) quantify the long-term durability of concrete waste forms as a function environmental parameters relevant to depository conditions, and (5) identify the formation of secondary phases or processes (microcracking) that influence radionuclide retention. Data obtained from this investigation provides valuable information for understanding the speciation, behavior, and fate of radionuclides immobilized within concrete wasteforms under vadose zone conditions and underscores the necessity for robust, multi-disciplinary performance assessments for concrete waste forms.},
doi = {10.1557/PROC-1193-349},
url = {https://www.osti.gov/biblio/1039134}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun May 24 00:00:00 EDT 2009},
month = {Sun May 24 00:00:00 EDT 2009}
}

Conference:
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