Investigation on solute transport in heterogeneous fracture of crystalline rock by flow-through test and micro X-ray CT

マイクロX線CT及び通液試験による結晶質岩の不均質割れ目中の物質移行の調査

深津 勇太  ; 舘 幸男  

Fukatsu, Yuta; Tachi, Yukio

Crystalline rocks such as granodiorites have been investigated as potential host rocks for the geological disposal of radioactive waste in many countries. Radionuclide transport in fractured crystalline rocks can be conceptualized by a dual-porosity model where radionuclides are transported by advective water flow through a fracture and are retarded by both diffusion and sorption into the surrounding rock matrix. Aperture variability within a fracture determines flow in a channel, whereas other areas of the fracture have almost stagnant water. The effect of different degrees of heterogeneity in fracture aperture distributions is critically important to quantify solute transport. In the present study, we identified flow channels and stagnant water zones in a fractured granodiorite by mean of a flow-through test, using imaging tracer coupled with micro X-ray CT measurements.