| Project/Area Number |
17360452
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear engineering
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| Research Institution | University of Tsukuba |
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Principal Investigator |
HATANO Yuko University of Tsukuba, Graduate School of System and Information Engineering, Associate Professor (60323276)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEWAKA Satoshi University of Tsukuba, Graduate School of System and Information Engineering, Associate Professor (80202167)
MOHRI Yoshiyuki Institute of Rural Engineering Soil Physics Laboratory, 土質研究室, Head (90373224)
HORI Toshikazu Institute of Rural Engineering Soil Physics Laboratory, 土質研究室, Researcher (20414451)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥6,430,000 (Direct Cost: ¥6,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2007: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2005: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Environmental technolory / Water pollution / Soil pollution / Fractal / Porous media / Anomalous diffusion / Radioactive waste / 水質汚濁・土壌汚染防止 / 移流分散 / 拡散 |
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| Research Abstract |
The model of Advection-Dispersion Equation (ADE) has been used in predicting the behavior of radioactive nuclides for underground storage of nuclear wastes. Recently, however, it has been pointed out that the ADE does not always properly reproduce the results of actual field tests or laboratory experiments. In this study, we concentrate on a new model, CTRW (Continuous-time Random Walk), thereby compare our experimental results with CTRW. We performed two kinds of experiments : (1) long-distance sandbox permeation tests, and (2) column tests with adsorptive heavy metal. In both experiments, we found that CTRW gives a better result than ADE does. Details of our findings are as follows. As for (1), we obtained experimental values of the longitudinal dispersion coefficient. The coefficient becomes larger when the flow distance becomes larger, and converges to an almost constant value. We found that this behavior is not consistent with the original CTRW, but a modified CTRW with cutoff time in the waiting time function. The assumption in the original CTRW (=includes infinity duration of the waiting time) may be too strong for reproducing the real experiments. As for (2), we tested two kinds of heavy metals, one is weakly adsorbed and the other is strongly adsorbed, and found that the latter is close to the original CTRW but the former is more close to cutoff-CTRW. We conclude that, in the analysis of radioactive waste repository, CTRW is worth to be considered.
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