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Misono, Toshiharu; Nakanishi, Takahiro; Sanada, Yukihisa; Shiribiki, Takehiko; Urabe, Yoshimi*; Tsuruta, Tadahiko
JAEA-Research 2022-010, 134 Pages, 2023/02
JAEA-Research-2022-010.pdf:8.45MB
An accident occurred at the TEPCO's Fukushima Daiichi Nuclear Power Station (1F) in 2011 and a large amount of radioactive materials were deposited around the 1F. Japan Atomic Energy Agency has continued to conduct research on the dynamics of radioactive materials after the accident. This report summarizes the results of the survey conducted in FY 2021 on the status of marine monitoring survey on radioactive substances. Furthermore, a seabed topography and sediments distribution survey was conducted in the coastal area off the Mano River from the Ohta River to understand the topography and sediment distribution. Furthermore, in order to evaluate the inflow of radioactive Cs from the river, the horizontal distribution of the radioactive Cs concentration on the surface sediment in front of the rivers was measured. As basic information on the effects of radioactive materials on marine products, the distribution status of fish was investigated. In addition, a demonstration test of water sampling and sediment sampling was conducted using an unmanned observation vessel. From these results, we estimated the distribution and its dynamics of radioactive Cs in the sediments in the front area on the 1F.
Tateishi, Ryo*; Shimada, Koji; Iwamori, Akiyuki*; Wada, Shinya*; Seno, Shotaro*; Nagata, Ken*
Chishitsugaku Zasshi (Internet), 128(1), p.63 - 64, 2022/04
The Tsuruga Fault is an active right-lateral strike-slip fault that is about 20 km in length and distributed in the northeast-southwest direction from the eastern part of Tsuruga City to the southern part of Mihama Town, Fukui Prefecture. The Tsuruga fault borders the Jurassic accretionary complex (mixed rock) and the late Cretaceous granite around the Oritodani area in the Shinjo district of Mihama-cho. Lateral bendings of valleys along the fault in this area are clear geomorphological signatures of fault activity. We briefly report newly found multiple fault outcrops at these bending points with photos of them. This research is the result of joint research by Kansai Electric Power Company, University of Toyama, and JAEA.
Yamaguchi, Masaaki; Kato, Tomoko; Suzuki, Yuji*; Makino, Hitoshi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 27(2), p.72 - 82, 2020/12
An efficient analytical tool to calculate temporal change of topography and repository depth due to uplift and erosion was developed for use in performance assessment of high level radioactive waste geological disposal. The tool was developed as ArcGIS model, incorporating simplified landform development simulation, to enable trial calculation of various conditions such as initial topography, uplift rate and its distributions, and repository location. This tool enables to support decision on which processes, features, and their changes should be taken into account for performance assessment, by calculating topography change and repository depth change under various conditions.
Takai, Shizuka; Kimura, Hideo*; Uchikoshi, Emiko*; Munakata, Masahiro; Takeda, Seiji
JAEA-Data/Code 2020-007, 174 Pages, 2020/09
JAEA-Data-Code-2020-007.pdf:4.23MB
The MIG2DF computer code is a computer program that simulates groundwater flow and radionuclide transport in porous media for the safety assessment of radioactive waste disposal. The original version of MIG2DF was released in 1992. The original code employs a two-dimensional (vertical or horizontal cross-section, or an axisymmetric configuration) finite-element method to approximate the governing equations for density-dependent saturated-unsaturated groundwater flow and radionuclide transport. Meanwhile, for geological disposal of radioactive wastes, landscape evolution such as uplift and erosion needs to be assessed as a long-term geological and climate events, considering site conditions. In coastal areas, the impact to groundwater flow by change of salinity distribution to sea level change also needs to be considered. To deal with these events in the assessment, we have revised the original version of MIG2DF and developed the external program which enables MIG2DF to consider unsteady landscape evolution. In these developments, this report describes an upgrade of MIG2DF (Version 2) and presents the configuration, equations, methods, and verification. This reports also give the explanation external programs of MIG2DF: PASS-TRAC (the particle tracking code), PASS-PRE (the code for dataset preparation), and PASS-POST (the post-processing visualization system).
Cs concentrations in east Japanese riversTsuji, Hideki*; Ishii, Yumiko*; Shin, M.*; Taniguchi, Keisuke*; Arai, Hirotsugu*; Kurihara, Momo*; Yasutaka, Tetsuo*; Kuramoto, Takayuki*; Nakanishi, Takahiro; Lee, S*; et al.
Science of the Total Environment, 697, p.134093_1 - 134093_11, 2019/12
Times Cited Count：17 Percentile：59.38(Environmental Sciences)To investigate the main factors that control the dissolved radiocesium concentration in river water in the area affected by the Fukushima Daiichi Nuclear Power Plant accident, the correlations between the dissolved Cs concentrations at 66 sites normalized to the average Cs inventories for the watersheds with the land use, soil components, topography, and water quality factors were assessed. We found that the topographic wetness index is significantly and positively correlated with the normalized dissolved Cs concentration. Similar positive correlations have been found for European rivers because wetland areas with boggy organic soils that weakly retain Cs are mainly found on plains. However, for small Japanese river watersheds, the building area ratio in the watershed strongly affected the dissolved Cs concentration.
Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06
In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.
Sakai, Toshihiro; Matsuoka, Toshiyuki
JAEA-Research 2015-004, 109 Pages, 2015/06
JAEA-Research-2015-004.pdf:141.42MB
JAEA-Research-2015-004-appendix(CD-ROM).zip:128.66MB
We update the geologic map and the database of the geological mapping published by Funaki et al. (2005a) and Ota et al. (2007) based on geological survey and topographical analysis data in and around the Horonobe area. There are many geological survey data which are derived from natural resources (petroleum, natural gas and coal, etc.) exploration in and around Horonobe-cho. We also use these data in addition to data in Funaki et al. (2005a) and Ota et al. (2007)'s data. As results of this report, we also construct a digital geologic map and a digital database of geological survey using GIS. These results can be expected to improve the precision of modeling and analyzing of geological environment, and its long-term evaluation.
*; *
JNC TJ7440 2000-005, 45 Pages, 2000/03
JNC-TJ7440-2000-005.pdf:2.72MB
no abstracts in English
Mukoyama, Sakae*; Inomata, Takayuki*; Makita, Hiroko*
PNC TJ7362 96-001, 74 Pages, 1996/03
None
; Yamazawa, Hiromi
Journal of Nuclear Science and Technology, 32(7), p.671 - 682, 1995/07
Times Cited Count：4 Percentile：43.23(Nuclear Science & Technology)no abstracts in English
Yamanoi, Tadayo*; Kato, Yoshiro*; Okazaki, Hikoya*
PNC TJ1361 95-001, 196 Pages, 1995/03
PNC-TJ1361-95-001.pdf:20.45MBPNC-TJ1361-95-001-attribute-list.pdf:13.11MB
In order to realize the R&D on "exhibiting potential of the geological disposal of radioactive waste", it is neccessary to grasp the geological condition on a nationwide scale, and evaluate its aptitude on the view-point of long-term safety. Geological stability and hydrogeological property of the rock, which are both essential indications of the geological condition, are closely related to the fractures in the rock. It is, therefore, very important to understand the spacial distribution and characteristics of the fracture systems in Japan.
; Yamazawa, Hiromi
JAERI-Research 94-040, 40 Pages, 1994/11
JAERI-Research-94-040.pdf:1.39MB
no abstracts in English
