Analysis of the Tracer Diffusion Phenomena through Cracks in the Porous Media by Means of X-Ray CT
- 1 Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan
Abstract
The migration process of contamination materials in the porous rock mass was visualized and analyzed by X-ray CT image data. In this study, Kimachi sandstone, which ha d approximately 26% porosity, was used as a rock sample. Here two cases of diffusion phenomena were analyzed. One is the case that solute diffuses into the porous rock mass from the crack surfaces, and it simulates the contamination process of rock mass. Another is the case that the solute diffuses out of the porous rock mass, and it simulates the process that the contamination materials spread from highly contaminated sources. It was found that the diffusion phenomena were clearly visualized by X-ray CT method. By introducing the parameter, coefficient of tracer density increment α , quantitative analysis of tracer density became possible, and the relation between the density distribution of tracer and the crack apertures and the relation between the density distribu tion and porosity distribution became clear .
- JNC, “Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan,” JNC Technical Report, Japan Nuclear Cycle Development Institute, Ibaraki, 2000.
- S. S. D. Foster, “The Chalk Groundwater Tritium Anomaly—A Possible Explanation,” Journal of Hydrology, Vol. 25, No. 1-2, 1975, pp. 159-165. doi:10.1016/0022-1694(75)90045-1
- M. Mazurek, W. R. Alexander and A. B. MacKenzie, “Contaminant Retardation in Fractured Shales: Matrixdiffusion and Redox Front Entrapment,” Journal of Contaminant Hydrology, Vol. 21, No. 1-4, 1996, pp. 71-84. doi:10.1016/0169-7722(95)00034-8
- P. M. Jardine, W. E. Sanford, J. P. Gwo, O. C. Reedy, D. S. Hicks, J. S. Riggs and W. B. Bailey, “Quantifying Diffusive Mass Transfer in Fractured Shale Bedrock,” Water Resource Research, Vol. 35, No. 7, 1999, pp. 2015-2030. doi:10.1029/1999WR900043
- E. A. Sudicky and Eo. Frind, “Contaminant Transport in Fractured Porous Media: Analytical Solutions for a System of Parallel Fractures,” Water Resource Research, Vol. 18, No. 6, 1982, pp. 1634-1642. doi:10.1029/WR018i006p01634
- H. H. Liu, S. Mukhopadhyay, N. Spycher and B. M. Kennedy, “Analytical Solutions of Tracer Transport in Fractured Rock Associated with Precipitation-Dissolution Reactions,” Hydrogeology Journal, Vol. 19, No. 6, 2011, pp. 1151-1160. doi:10.1007/s10040-011-0749-7
- R. A. Freeze and J. A. Cherry, “Groundwater,” Prenticehall, Englewood Cliffs, 1979.
- H. Saegusa, et al., “Final Report on the Surface-Based Investigation (Phase I) at the Mizunami Underground Laboratory Project,” JAEA-Research, Japan Atomic Energy Agency, Ibaraki, 2007.
- K. Ota, et al., “Horonobe Underground Research Laboratory Project Synthesis of Phase I Investigations 2001-2005,” JAEA-Research, Japan Atomic Energy Agency, Ibaraki, 2007.
- Y. Ijiri, A. Sawada, K. Sakamoto, W. S. Dershowitz, M. Uchida, K. Ishiguro and H. Ueki, “Evaluation of Scale Effects on Hydraulic Characteristics of Fractured Rock Using Aperture Network Model,” Journals of the Japan Society of Civil Engineers, Vol. 694, 2001, pp. 229-243.
- Y. Ijiri, A. Hata, K. Hosono and A. Sawada, “Study on Uncertainties of Radionuclide Migration Parameter Values Obtained from in Situ Tracer Tests,” Journals of the Japan Society of Civil Engineers, Vol. 778, No. III-69, 2004, pp. 85-97.
- K. Hatanaka, M. Uchida, M. Shimo, H. Yamamoto and S. Kumamoto, “Laboratory Experiment on the Hydraulic and Transport Properties of Fractured Soft Sedimentary Rocks,” Proceedings of the 33rd Annual Symposium on Rock Mechanics, Tokyo, 29-30 January 2004, pp. 313-318.