Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tachi, Yukio; Ito, Tsuyoshi*; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
Water Resources Research, 54(11), p.9287 - 9305, 2018/11
Times Cited Count：5 Percentile：26.11(Environmental Sciences)Effects of fine-scale surface alterations on radionuclide migration in fractured crystalline rocks were investigated by a comprehensive approach coupling a series of laboratory tests, microscopic observations and modelling, using a single fractured granodiorite sample from the Grimsel Test Site, Switzerland. Laboratory tests including through-diffusion, batch sorption and flow-through tests using five tracers indicated that tracer retention was consistently in the sequence of HDO, Se, Cs, Ni, Eu, and as well as showing the existence of a diffusion-resistance layer near the fracture surface, cation excess and anion exclusion effects for diffusion. Microscale heterogeneities in structural properties around the fracture were clarified quantitatively by coupling X-ray CT and EPMA. A three layer model including weathered vermiculite, foliated mica and undisturbed matrix layers, and their properties such as porosity, sorption and diffusion parameters, could provide a reasonable interpretation for breakthrough curves and concentration distributions near fracture surface of all tracers, measured in flow-through tests.
Tachi, Yukio; Ito, Tsuyoshi; Akagi, Yosuke*; Sato, Hisao*; Martin, A. J.*
no journal, ,
The effects of heterogeneity at fracture surface on radionuclides migration in fractured crystalline rocks was investigated by laboratory migration experiments, microscopic observations and detailed modelling, using a single fractured granodiorite sample from the Grimsel Test Site (GTS), Switzerland. The tracer migration behaviors in fracture and matrix parts were evaluated by series of laboratory experiments including through-diffusion and flow-through experiments. Mineral distributions from fracture surface to matrix were evaluated by X-ray CT, and were validated by comparing the elemental mapping measured by EPMA. Based on the microscopic observations by X-ray CT and EPMA, the aperture and connectivity in fracture and minerals distribution near fracture surface were quantitatively evaluated. The heterogeneous multi-layered model assuming a weathered vermiculite zone, a foliated mica zone and rock matrix was possible to provide a reasonable interpretation for measured breakthrough curves of all tracers.
