Studies Of Cement Grouts And Grouting Techniques For Sealing A Nuclear Fuel Waste Disposal Vault

1988 ◽  
Vol 137 ◽  
Author(s):  
Maria Onofreic ◽  
Malcolm N. Gray ◽  
L. Douglas Keil ◽  
Roland Pusch

AbstractA cement-based grout (90% Type 50, 10% silica fume, 0.4 < water-to-cement ratio, w/c < 0.6) has been used in field trials at AECL's Underground Research Laboratory in Canada and at the OECD/NEA Stripa Mine in Sweden, to evaluate suitable grouts and grouting techniques that could be used for sealing a nuclear fuel waste disposal vault mined deep in granite. Laboratory studies have been carried out to determine the following grout properties: hydraulic conductivity (k); resistance to piping and erosion during setting; influence of grout on the pH and chemical composition of water permeating grouted rock; and the ability of the grout to self-seal after fracturing.Laboratory tests have confirmed the low intrinsic k of these cement mixtures (10−14 m/s). Using a specially developed cone-in-cone apparatus, we have studied the effect of fracture dilation and temperature changes on the k of thin films of cement. If fractured, the grout has an ability to self-seal and the rate of self-sealing increases with increasing temperature.The pH and ionic composition of the water permeating grouted fractured granite rock were found to vary with grouted fracture aperture and grout/rock volume ratio. The field tests demonstrated that grout can penetrate and seal very fine fissures (apertures less than 50 μm).

1996 ◽  
Vol 42 (4) ◽  
pp. 401-409 ◽  
Author(s):  
M. Gascoyne

The concept for disposal of Canada's nuclear fuel waste in a geologic environment on the Canadian Shield has recently been presented by Atomic Energy of Canada Limited (AECL) to governments, scientists, and the public, for review. An important part of this concept concerns the geochemical environment of a disposal vault and includes consideration of rock and groundwater compositions, geochemical interactions between rocks, groundwaters, and emplaced vault materials, and the influences and significance of anthropogenic and microbiological effects following closure of the vault. This paper summarizes the disposal concept and examines aspects of the geochemical environment. The presence of saline groundwaters and reducing conditions at proposed vault depths (500–1000 m) in the Canadian Shield has an important bearing on the stability of the used nuclear fuel, its container, and buffer and backfill materials. The potential for introduction of anthropogenic contaminants and microbes during site investigations and vault excavation, operation, and sealing is described with examples from AECL's research areas on the Shield and in their underground research laboratory in southeastern Manitoba. Keywords: nuclear waste disposal, geochemistry, Canadian Shield, groundwater chemistry.


1981 ◽  
Vol 6 ◽  
Author(s):  
Donald J. Cameron

ABSTRACTNuclear fuel waste disposal research in Canada is concentrating on hard-rock disposal. The research programs concerned with the man-made components of the disposal system are reviewed. Irradiated fuel and solidified reprocessing wastes are both being researched, as are durable containers, and buffer and backfill materials. This review concentrates mainly on the more scientific aspects of the research, which contribute to the selection of preferred options for the various components of the system, and which support directly or indirectly the safety analysis of the disposal concept. Some technology development is included in the program now, and this is expected to expand as confidence in the acceptability of the disposal concept grows.


1993 ◽  
Vol 13 (2) ◽  
pp. 153-170 ◽  
Author(s):  
G.A. Bird ◽  
M. Stephenson ◽  
R.J. Cornett

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