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Shimemoto, Hidenori; Yamaguchi, Masaaki; Wakasugi, Keiichiro; Shibata, Masahiro
JAEA-Research 2013-012, 35 Pages, 2013/10
JAEA-Research-2013-012.pdf:8.16MB
In this study, we focus on uplift and erosion and climatic and sea-level changes among natural phenomena and pick up fluvial erosion is main and means large velocity between different type of erosion in Japan, and developed conceptual modeling of geomorphic change due to fluvial erosion with respect to fluvial erosion and sedimentation system, to evaluate the potential impact of exposure case of high level radioactive waste to land surface. Conceptual modeling of geomorphic change caused by fluvial erosion is developed with riverhead and downriver, such catchment areas are not treated until now, by conceptualization of geomorphic change on river due to uplift and denudation and climatic and sea-level changes for about last hundred and twenty thousand years. Furthermore, we analysis the depth and width of deepening and lateral erosion around river channel using the data of alluvium and show an example of the setup method concerning dimension on conceptual model to estimate the erosion volume contribute to the evaluation as to high level radioactive waste exposure process to land surface. We illustrate by an example the dimension as to valley within the central Japanese mountains using DEM data on conceptual model at riverhead. We develop conceptual modeling of geomorphic change on the basis of the feature on fluvial erosion in Japan and set basic intelligence to evaluate the potential impact of repository exposure to land surface caused by fluvial erosion, based on above study.
Wakasugi, Keiichiro; Nakajima, Kunihiko*; Shimemoto, Hidenori; Shibata, Masahiro; Yamaguchi, Masaaki
Proceedings of 21st International Conference on Nuclear Engineering (ICONE-21) (DVD-ROM), 9 Pages, 2013/07
In Japan, uplift and erosion scenarios must be analysed since this natural phenomena would be inevitable at most sites in Japan. It's increasingly important to enhance the confidence of the assessment for the uplift and erosion scenarios, as no assessment cut-off times have yet been defined. In this context, this study carried out bounding analysis to find out parameter conditions to satisfy hypothetical dose criteria. The results show that there are no cases that satisfy 10 microSv/y. However, all cases are below 300 microSv/y. The discussion also implies that to accelerate the release from the EBS for minimising the dose in later phase is inadequate and ineffective at all, due to multiple barriers and multiple safety functions. In principal, the influence of uplift and erosion should be reduced by appropriate site selection and design as much as possible to ensure the sufficient nuclides decay while the repository is staying at the deep underground.
Kawamura, Makoto*; Shimemoto, Hidenori; Shibata, Masahiro
no journal, ,
no abstracts in English
Shimemoto, Hidenori; Shibata, Masahiro; Maekawa, Keisuke; Kawamura, Makoto*
no journal, ,
no abstracts in English
Yamaguchi, Masaaki; Wakasugi, Keiichiro; Koo, Shigeru; Shimemoto, Hidenori; Shibata, Masahiro
no journal, ,
Since its tectonically active and humid setting, uplift and erosion scenarios must be covered in safety assessment of HLW in Japan. This study suggests a new methodology for scenario and parameter setting for uplift and erosion scenario assessment, on the bases of long-term geomorphic change by using previous equations based on correlative relationship between relief, altitude, and erosion.
Shimemoto, Hidenori; Wakasugi, Keiichiro; Shibata, Masahiro; Yamaguchi, Masaaki
no journal, ,
In the safety assessment of radioactive waste disposal, consideration of evolution of geological environment is requested. The disposal facility can be expected to come close to ground surface, when continuous uplift and erosion for long-term is assumed. In general, geological conditions in near-surface underground is different from those in deep-underground due to weathering. Preparing for such scenario and nuclides migration analysis, information regarding weathered zone are surveyed and arranged. As a result, 37data of depth (thickness) of weathered zone were extracted. Then the data distribution and characteristics of thick weathered case was discussed. The relation between weathered zone and landform was also discussed. Categorization into four patterns of the relation are proposed, and factors which contribute to the difference of the patterns are discussed. Regarding the geological property/condition in the weathered zone, quantitative information on hydraulic and chemical conditions is limited, to the contrary data on uniaxial strength and porosity are available. For the sake of condition setting for near-surface underground in the long-term safety assessment, continuous survey of information is important.
