[H-CG20] Nuclear Energy and Geoscience

[HCG20-P01] Topographic Information for the development of a model to evaluate the performance assessment of HLW disposal repository
~Part 1: River cross section data

*Nariaki Nishiyama¹, Makoto Kawamura¹, Tetsuya Komatsu¹, Hua Jia², Yukiko Koizumi², Toshimichi Nakanishi³, Umeda Koji⁴ (1.Tono Geoscience Center, Japan Atomic Energy Agency, 2.Mitsubishi Materials Techno Co., 3.Museum of Natural and Environmental History, Shizuoka, 4.Graduate School of Science and Technology, Hirosaki University)

Keywords:Geological disposal, River cutting, Geographic Information System, Performance assessment model, Landform development simulation

One of the key issues in the investigation and assessment technologies related to uplift and denudation, which are important for site selection and safety assessment of geological disposal of HLW, is the need to enable quantitative assessment of changes and their effects on the surface topography and geological environment in the future due to river cutting. In the study of performance assessment models that take into account landform development, simulations are based on information on river cross-section geometry, however information on river cross-section geometry has not been well organized. Against this background, the authors have obtained river cross-section data mainly for major rivers in Japan by GIS topographic analysis using the GSI’s 10 m DEM (Kawamura et al., 2023). In this study, we expanded the data by increasing the number of target rivers and organized the data.
In this presentation, we report the results of the comparison of cross-section profiles for each river, and the results of the grouping of specific height change from downstream to upstream and horizontal distance from riverbed to peak elevation by uplift rate, geology, climatic conditions, and other factors. These results will contribute to the validation of future projections such as landform development simulations and performance assessment models.
This study was funded by the Ministry of Economy, Trade and Industry (METI), Japan as part of its R&D supporting program titled “Establishment of Technology for Comprehensive Evaluation of the Long-term Geosphere Stability on Geological Disposal Project of Radioactive Waste (JPJ007597) (Fiscal Years 2023)”.