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Nakanishi, Toshimichi*; Komatsu, Tetsuya; Ogata, Manabu; Kawamura, Makoto; Yasue, Kenichi*
Gekkan Chikyu "Kiso deta Kara Kangaeru Dai Yonkigaku No Shintenkai-I" Gogai No.71, p.148 - 155, 2022/02
The formation process of terrace topography was investigated by observing and analyzing boring core samples collected in the middle reaches of the Kumano River. It was assumed that the older terrace topography was distributed higher than the current riverbed surface. However, since tributary debris flow deposits may be thickly distributed beneath the old gyre river valley, care must be taken when using the surface of the ground as an index of uplift and erosion.
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.
Shimada, Taro; Takeda, Seiji; Mukai, Masayuki; Munakata, Masahiro; Tanaka, Tadao
Materials Research Society Symposium Proceedings, Vol.1744, p.229 - 234, 2015/04
Integrated safety assessment methodology which analyzes radionuclide migration reflecting the spatial and temporal changes of disposal systems was developed for a geological disposal site with uplift and denudation, and then some case analyses for an assumed site with sedimentary rocks were carried out. The combination of uniform uplift and denudation has the most effect on the radionuclide migration because the groundwater flow velocity increases with decreasing the depth from the ground surface. In the case without denudation, tilted uplift has more effect than uniform uplift because flow velocity in tilted uplift increase with increasing hydraulic gradient. The long-term change of the geological structures including the uplift and denudation, the hydraulic conditions, and the recharge and outlet of the groundwater around a candidate site should be carefully investigated to determine the appropriate the place,depth and layout of the repository.
Makino, Hitoshi; ; Miyahara, Kaname
JNC TN8400 2000-033, 74 Pages, 2000/11
JNC-TN8400-2000-033.pdf:9.19MB
Natural phenomena is one of the potential factors perturbing the long-term stability of the geological environment, and for natural phenomena, it is necessary to consider uncertainties relevant to time, frequency and effect. Therefore it will be important to have information about the potential impacts of natural phenomena on the safety functions of geological disposal system in the future by assuming that natural phenomena perturbs the safety functions of the geological disposal system. In this report, we have considered 4 natural phenomena, 'uplift, subsidence and denudation', 'climatic and sea-level changes', 'earthquakes and fault movement' and 'volcanism', which had been extracted by investigation in foreign countries and by considering the characteristics of Japan as natural phenomena which may perturb the long-term stability of the geological environment. And we have considered mainly typical effects of naturaI phenomena on geological environment and investigated the typical impacts of those natural phenomena on the safety functions of the geological disposal system. On perturbation scenarios, the maximum of total doses have been less than regulatory guidelines in foreign countries in all situations except the cases assuming that a new fault, which causes significant pathway of groundwater flow and nuclide migration, intersects the waste packages. In the case, the maximum of total doses may reach the same level as regulatory guidelines in foreign countries or natural radiation exposure in Japan depending on fault generation time or grandwater flow rate through the fault. And, on isolation failure scenarios, it has been implied that nuclide mass/flux originated from geological disposal is comparable level with nuclide mass/flux in natural environment. These results could give useful information about the potential impacts of natural phenomena on the safety functions of geological disposal system, and also could show the potential importance of ...
Okuda, Katsuzo*; Takebe, Shinichi; Sakamoto, Yoshiaki; Hagiwara, Shigeru*; Ogawa, Hiromichi
JAERI-Review 99-023, p.100 - 0, 1999/10
JAERI-Review-99-023.pdf:4.63MB
no abstracts in English
; ; Shimizu, Kazuhiko; Miyahara, Kaname; ; Hasegawa, Hiroshi; Makino, Hitoshi
JNC TN1400 99-007, 497 Pages, 1999/04
None
*; Fuse, Keisuke*; *; Yasuda, Kenya*
PNC TJ7454 97-001, 536 Pages, 1997/03
no abstracts in English
Takano, Toyoji*; Sasaki, Yutaka*; Fuse, Keisuke*; Saito, Akira*; Sato, Yoshikazu*
PNC TJ1454 96-001, 295 Pages, 1996/03
None
Okubo, Hiroo*
PNC TJ1222 94-002, 60 Pages, 1994/03
no abstracts in English
Shimada, Taro; Takubo, Kazuya; Takeda, Seiji; Tanaka, Tadao
no journal, ,
In long-term safety assessment of geological disposal system, it is necessary to evaluate the impact on the nuclides migration where groundwater flow and water composition are changed with decreasing a depth of the repository by uplifts and denudation. Therefore, we developed an integrated safety assessment methodology for uplifts and denudation where nuclides migration was evaluated reflecting temporal and spatial changes of parameters of natural and engineered barriers such as distribution coefficient, porosity and groundwater velocity, which were obtained by calculation of groundwater flow, salt water distribution and long-term transition of engineered barriers. The methodology was applied to an assumed disposal site composed of sedimentary rocks with uplift and denudation. Migration parameters of engineered barrier such as coefficient of water permeability and porosity of buffer material were evaluated considering the interaction between overpack and surrounding bentonite clay under the condition of water composition. Migration parameters of the natural barrier such as distribution coefficient were determined by the combination of the geology section and water composition section on the migration pathway from the repository to the outlet of the natural barrier at the depth of 40m from the surface. The migration fluxes of some radionuclides at the outlet of natural barrier were evaluated and then the impacts on nuclides migration by uplifts and denudation were compared.
Takeda, Seiji; Munakata, Masahiro; Namekawa, Maki; Sakai, Ryutaro; Shimada, Taro; Tanaka, Tadao
no journal, ,
In long-term safety assessment of geological disposal system, it is necessary to evaluate the impact on the radionuclides migration where groundwater flow and water composition are changed with decreasing a depth of the repository by uplifts (two types: uniform and tilted) and denudation. We developed an integrated safety assessment methodology for uplifts and denudation where radionuclides migration analysis was combined with calculation results of groundwater flow and salt concentration distribution in a disposal site and of long-term transition of engineered barriers to estimate their properties and migration parameters. Assuming disposal site composed of sedimentary rocks with uplifts and denudation, we carried out the sensitivity analyses on groundwater velocity and salt concentration and indicated the requirements for future investigation of natural barrier related to uplifts and denudation at a candidate site from the estimation results.
Yamaguchi, Tetsuji
no journal, ,
no abstracts in English
Shimada, Taro; Uchikoshi, Emiko*; Takai, Shizuka; Takeda, Seiji
no journal, ,
Long-term topographic change due to uplift, denudation and eustasy may change the field of groundwater flow and nuclide migration when radioactive wastes are disposed at the repository near the sea. In this report, we constructed the frame work for evaluating uncertainties of future topograophic changes. Using the evaluation code under developing at JAEA, we tried evaluating the future topographic change until 0.125k years after for catchment basin near the sea.
Sakamoto, Michihito*; Wakasugi, Keiichiro*; Kabasawa, Satsuki; Yamaguchi, Masaaki
no journal, ,
no abstracts in English
Kabasawa, Satsuki; Sakamoto, Michihito*; Takahashi, Yuta; Yamaguchi, Masaaki
no journal, ,
no abstracts in English
