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Title: Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes

Abstract

At the former nuclear weapon production site in Hanford, WA, caustic radioactive tank waste leaks into subsurface sediments and causes dissolution of quartz and aluminosilicate minerals, and precipitation of sodalite and cancrinite. This work examines changes in pore structure due to these reactions in a previously-conducted column experiment. The column was sectioned and 2D images of the pore space were generated using backscattered electron microscopy and energy dispersive X-ray spectroscopy. A pre-precipitation scenario was created by digitally removing mineral matter identified as secondary precipitates. Porosity, determined by segmenting the images to distinguish pore space from mineral matter, was up to 0.11 less after reaction. Erosion-dilation analysis was used to compute pore and throat size distributions. Images with precipitation had more small and fewer large pores. Precipitation decreased throat sizes and the abundance of large throats. These findings agree with previous findings based on 3D X-ray CMT imaging, observing decreased porosity, clogging of small throats, and little change in large throats. However, 2D imaging found an increase in small pores, mainly in intragranular regions or below the resolution of the 3D images. Also, an increase in large pores observed via 3D imaging was not observed in the 2D analysis. Changes inmore » flow conducting throats that are the key permeability-controlling features were observed in both methods.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1037943
Report Number(s):
PNNL-SA-86161
Journal ID: ISSN 0169-7722; JCOHE6; KP1702030; TRN: US1201719
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Contaminant Hydrology
Additional Journal Information:
Journal Volume: 131; Journal Issue: 1-4; Journal ID: ISSN 0169-7722
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; ALUMINIUM SILICATES; DISSOLUTION; ELECTRON MICROSCOPY; IMAGES; NUCLEAR WEAPONS; PORE STRUCTURE; POROSITY; PRECIPITATION; QUARTZ; RADIOACTIVE WASTE DISPOSAL; SEDIMENTS; SILICATE MINERALS; TANKS; UNDERGROUND STORAGE; X-RAY SPECTROSCOPY; mineral precipitation; porosity; SEM; pore size distribution; erosion dilation

Citation Formats

Crandell, L E, Peters, Catherine A, Um, Wooyong, Jones, Keith W, and Lindquist, W Brent. Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes. United States: N. p., 2012. Web. doi:10.1016/j.jconhyd.2012.02.002.
Crandell, L E, Peters, Catherine A, Um, Wooyong, Jones, Keith W, & Lindquist, W Brent. Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes. United States. https://doi.org/10.1016/j.jconhyd.2012.02.002
Crandell, L E, Peters, Catherine A, Um, Wooyong, Jones, Keith W, and Lindquist, W Brent. 2012. "Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes". United States. https://doi.org/10.1016/j.jconhyd.2012.02.002.
@article{osti_1037943,
title = {Changes in the pore network structure of Hanford sediment after reaction with caustic tank wastes},
author = {Crandell, L E and Peters, Catherine A and Um, Wooyong and Jones, Keith W and Lindquist, W Brent},
abstractNote = {At the former nuclear weapon production site in Hanford, WA, caustic radioactive tank waste leaks into subsurface sediments and causes dissolution of quartz and aluminosilicate minerals, and precipitation of sodalite and cancrinite. This work examines changes in pore structure due to these reactions in a previously-conducted column experiment. The column was sectioned and 2D images of the pore space were generated using backscattered electron microscopy and energy dispersive X-ray spectroscopy. A pre-precipitation scenario was created by digitally removing mineral matter identified as secondary precipitates. Porosity, determined by segmenting the images to distinguish pore space from mineral matter, was up to 0.11 less after reaction. Erosion-dilation analysis was used to compute pore and throat size distributions. Images with precipitation had more small and fewer large pores. Precipitation decreased throat sizes and the abundance of large throats. These findings agree with previous findings based on 3D X-ray CMT imaging, observing decreased porosity, clogging of small throats, and little change in large throats. However, 2D imaging found an increase in small pores, mainly in intragranular regions or below the resolution of the 3D images. Also, an increase in large pores observed via 3D imaging was not observed in the 2D analysis. Changes in flow conducting throats that are the key permeability-controlling features were observed in both methods.},
doi = {10.1016/j.jconhyd.2012.02.002},
url = {https://www.osti.gov/biblio/1037943}, journal = {Journal of Contaminant Hydrology},
issn = {0169-7722},
number = 1-4,
volume = 131,
place = {United States},
year = {2012},
month = {4}
}