Chemical, Physical and Engineering Characterization Of Candidate Backfill Clays and Clay Admixtures for a Nuclear Waste Respository-Part I

1981 ◽  
Vol 6 ◽  
Author(s):  
Sudesh K. Singh
Keyword(s):  
Nuclear Waste ◽  
Morphological Changes ◽  
Deionized Water ◽  
Engineering Properties ◽  
Nuclear Waste Repository ◽  
Exchange Cation ◽  
Mineral Components ◽  
Waste Repository ◽  
Mineralogical Compositions

ABSTRACTFourteen Canadian clays and clay admixtures were subjected to simulated nuclear waste repository environments. The present work is concerned with the montmorillonite-dominant materials only. The montmorillonite-dominant samples showed significant leaching on interaction with deionized water. On heating the samples at 200°C for 500 hours, montmorillomites lost intermicellar water completely and acquired cusp-like to cylindrical morphologies. The loss of water and the morphological changes in montmorillonites significantly altered the engineering characteristics. Permeability, shrinkage limits, compactability and shear strength varied in response to the dominant exchange cation in the structure of montmorillonites and the presence of other mineral components in the materials. The synthetic granite water reacted with montmorillonites and led to changes in chemical and mineralogical compositions, crystalline state and engineering properties.

Geotechnical Materials Considerations for Conceptual Repository Design in the Palo Duro Basin, Texas

1983 ◽  
Vol 26 ◽  
Author(s):  
W. S. Versluis ◽  
M. A. Balderman
Keyword(s):  
Nuclear Waste ◽  
Field Testing ◽  
Engineering Properties ◽  
Nuclear Waste Repository ◽  
Material Response ◽  
Materials Properties ◽  
Geologic Materials ◽  
Conceptual Designs ◽  
Waste Repository ◽  
Representative Samples

ABSTRACTThe Palo Duro Basin is only one of numerous potential repository locations for placement of a nuclear waste repository. Conceptual designs in the Palo Duro Basin involve considerations of the character and properties of the geologic materials found on several sites throughout the Basin. The first consideration presented includes current basin exploration results and interpretations of engineering properties for the basin geologic sequences.The next consideration presented includes identification of the characteristics of rock taken from the geologic sequence of interest through laboratory and field testing. Values for materials properties of representative samples are obtained for input into modeling of the material response to repository placement. Conceptual designs which respond to these geotechnical considerations are discussed.

Experimental Interaction of Basalt, Bentonite, and Water: Implications for Groundwater Chemistry in Waste Package Packing Material in a Nuclear Waste Repository

1987 ◽  
Vol 112 ◽  
Author(s):  
Gail L. McKeon ◽  
E. C. Thornton ◽  
D. J. Halko ◽  
M. I. Wood
Keyword(s):  
Nuclear Waste ◽  
Near Field ◽  
Sodium Concentration ◽  
Packing Material ◽  
Deionized Water ◽  
Solution Chemistry ◽  
Nuclear Waste Repository ◽  
Waste Package ◽  
Waste Repository ◽  
C 30

AbstractExperiments have been conducted by the Basalt Waste Isolation Project (BWIP) to assess changes in solution chemistry in the near-field environment of a nuclear waste repository in basalt. These Dickson autoclave experiments were carried out using Grande Ronde basalt ± bentonite and synthetic groundwater or deionized water at 300°C, 30 MPa, and solution-to-solid mass ratio of 10 for up to two years. Groundwater solution changes during reaction of the basalt and basalt/bentonite included initial decreases in pH and sodium concentration presumably due to smectite formation. This initial trend subsequently reversed in the basalt system with pH rising to ca. 7.5 and sodium increasing to the starting value. Steady state pH values for the basalt/bentonite system were ca. 6.4. The basalt + deionized water test exhibited a constant rise in pH to ca. 7.9 and release of sodium to solution in response to basalt dissolution. Slightly oxidizing conditions characterized the early part of all of the experiments followed by a decrease in fO2 to 10−31 to 10−32 These results are consistent with other work at similar and lower temperatures, suggesting that the packing material will react in the waste package environment to produce slightly alkaline, reducing conditions.

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