Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 43

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

JAEA Reports

Compilation of information on uplift of the last hundred thousand years in the Japanese Islands

Nomura, Katsuhiro; Tanikawa, Shinichi*; Amamiya, Hiroki; Yasue, Kenichi

JAEA-Data/Code 2016-015, 49 Pages, 2017/03

JAEA-Data-Code-2016-015.pdf:2.88MB

The uplift of the last hundred thousand years in the Japanese Islands has been acquired mainly using marine and river terraces. We arranged information regarding the uplift in a table. This data is one of the useful information for the development of the investigation technology of uplift and for the research of the landform evolution in Japanese islands.

Journal Articles

Numeral simulation of longitudinal river profile considering fluvial sediment transportation

Tanikawa, Shinichi; Sanga, Tomoji*; Yasue, Kenichi

Chikei, 37(2), p.189 - 207, 2016/04

JP, 2009-239446   Patent publication (In Japanese)

Existing simulation methods of long-term fluvial processes, represented as conventional difference scheme of diffusion equation, cannot control about the expression of sediment transportation satisfactorily, particularly around confluences in middle and lower reach of the river. To address this, we newly developed a numeral model and simulation program of fluvial processes, in which sediment outflux is distributed to multiple grids with the formula that enlarges the fluvial transport efficiency downstream as a function of grain-size and drainage area (named "transport distance increment curve"). This formula can control the concavity of longitudinal profile. With this model, analyses about expressions of geomorphic development in longitudinal river profile were carried out. As a result, it was confirmed that, with accurate settings of parameters, this model can yield features of river profiles, considering sediment transportation around confluences. It is believed from the above that this model enables the expression of fluvial topography as seen in nature, by translating the concept of long-term fluvial process into parameters.

Journal Articles

Study on index of erosion rate in inland mountains; Case study using old river valley around detached meander core

Yasue, Kenichi; Takatori, Ryoichi*; Tanikawa, Shinichi*; Ninomiya, Atsushi*; Tanase, Atsushi*; Furusawa, Akira*; Tajikara, Masayoshi*

Chishitsugaku Zasshi, 120(12), p.435 - 445, 2014/12

Estimating the rate of change in landforms and geological environments due to erosion is important when assessing the safety of the geological disposal of high-level radioactive waste in Japan. The aim of this study is to develop an index of erosion rates in inland mountains. We focused on circular abandoned channels, which are old river valleys around detached meander cores formed by the cut-off of incised meandering rivers. The channels can be useful for estimating incision rates because they occur at a range of elevations throughout the Japanese Islands. We undertook a case study to determine the incision rate using a circular abandoned channel in the middle reaches of the Kumanogawa River in the Kii Peninsula, where many circular abandoned channels have been identified. We obtained undisturbed core samples of old river channel deposits and angular gravel deposits that overlie the circular abandoned channel. The old river channel deposits have been emergent since at least MIS5, based on an analysis of the soil color in angular gravel deposits. The incision rate, as calculated from this age and the difference in elevation between the abandoned and present channels, is less than about 0.9 m/ky. This study shows that analyses of circular abandoned channels can yield estimates of incision rates and potentially also uplift rates. More accurate estimates of incision rates require further studies of the dating and evolution of sediments that overlie circular abandoned channels.

Journal Articles

Geological predictions for the long-term isolation of radioactive waste based on extrapolating uniform mode and rate of crustal movements

Umeda, Koji; Tanikawa, Shinichi; Yasue, Kenichi

Chigaku Zasshi, 122(3), p.385 - 397, 2013/07

Long-term predictions of geological and tectonic disturbances are key issues for safety assessment of radioactive waste disposal, especially in the Japanese Islands. The geological predictions should be performed by extrapolating consistent mode and rate of crustal deformation during the neotectonic time frame. Multiple lines of geological evidence in Japan strongly suggests that the present mode of tectonics began during the late Pliocene to early Quaternary, and was fully developed by the middle Pleistocene. The uncertainty in predictions beyond the steady state crustal deformation would, in general, increase for long-term predictions using the extrapolation procedure. Consequently, the future geological and tectonic disturbances can be estimated with relatively high reliability during the next 100,000 years in Japan.

JAEA Reports

Development of database on circular abandoned channel in Japan

Takatori, Ryoichi; Yasue, Kenichi; Tanikawa, Shinichi*; Ninomiya, Atsushi*; Tanase, Atsushi*

JAEA-Data/Code 2012-028, 15 Pages, 2013/03

JAEA-Data-Code-2012-028.pdf:34.12MB
JAEA-Data-Code-2012-028-appendix(CD-ROM).zip:0.52MB

To develop a method for estimating late Quaternary uplift rates of inland mountainous terrains where fluvial terraces are poorly developed, we focused on "circular abandoned channels", formed by meander cut-offs or river capture of an incised meandering river. We studied about 1,000 circular abandoned channels distributed throughout the Islands of Japan, and developed GIS database on circular abandoned channel in Japan. This database contains formation process, relative heights, degree of dissection and bedrocks of circular abandoned channels. Circular abandoned channels are distributed in inland mountainous terrains, where late Quaternary uplift rates are unknown, and indicate different relative heights along the same river. Relative heights tend to correlate with degree of dissection of the circular abandoned channels, which may indicate that degree of dissection correlate with ages of abandonment of circular abandoned channels.

Journal Articles

Spatial patterns of initiation ages of active faulting in the Japanese Islands

Doke, Ryosuke; Tanikawa, Shinichi; Yasue, Kenichi; Nakayasu, Akio; Niizato, Tadafumi; Umeda, Koji; Tanaka, Takenobu*

Katsudanso Kenkyu, (37), p.1 - 15, 2012/09

Based on the collection and analysis of existing information, we clarified a spatial distribution of started age of present faulting pattern on active fault in Japanese Islands. The number of active faults which started its activities are gradually increased from about 3 Ma, dramatically increased after 1.5 Ma, and peaked at around 0.5 Ma. After 1.5 Ma, active faults which types of activity or trends are different from previously started active faults are developed. Therefore, there are plural types of active faults in the present tectonic field in Japan. After the peak around 0.5 Ma, newly developed active faults are decreased. It is possibly that newly developed active faults are undetectable; therefore, it is needed to develop new technics for detecting and assessing non-distinguishing active faults.

JAEA Reports

Collection and analysis of existing information on applicability of investigation methods for estimation of beginning age of faulting in present faulting pattern

Doke, Ryosuke; Yasue, Kenichi; Nakayasu, Akio; Niizato, Tadafumi; Tanikawa, Shinichi; Tanaka, Takenobu*; Aoki, Michinori*; Sekiya, Ayako*

JAEA-Research 2011-031, 109 Pages, 2011/12

JAEA-Research-2011-031.pdf:7.23MB

In this study, existing information related to methods for the estimation of the beginning age of the faulting in the present faulting pattern on the active fault were collected and reviewed. A principle of method, noticing points and technical know-hows in the application of the methods, data uncertainty, and so on were extracted from the existing information. Based on these extracted information, task-flows indicating working process on the estimation of the beginning age for the faulting of the active fault were illustrated on each method. Additionally, the distribution map of the beginning age with accuracy of faulting in the present faulting pattern on the active fault was illustrated.

Journal Articles

Estimation method of uplift during late Quaternary in an inland area; Case study of fluvial terraces along the Kaburagawa river and Tokigawa river

Yasue, Kenichi; Tajikara, Masayoshi*; Tanikawa, Shinichi; Sugai, Toshihiko; Yamada, Koji*; Umeda, Koji

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 18(2), p.51 - 62, 2011/12

We attempt to improve the reliability of the TT method, quantitative estimation of inland uplift rate based on the model in which river bed elevation is controlled by the climate change. In order to recognize fluvial terraces in the glacial epoch, it is important to note that flood deposit and phytolith as indicators of the determination of the emergence horizon and the estimate of the paleoclimate, respectively. The identification of thick sediments suggesting the decline of the tractive force in the glacial epoch are also useful for highly accurate comparison and chronology of the terrace. This paper shows that the synthetic examination based on many data obtained by these techniques enables a highly accurate comparison and chronology of the terrace to estimate uplift for the last 100,000 years with high reliability.

JAEA Reports

Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal years 2010

Yasue, Kenichi; Asamori, Koichi; Tanikawa, Shinichi; Yamada, Kunimi; Yamasaki, Seiko; Kokubu, Yoko; Niwa, Masakazu; Doke, Ryosuke; Kusano, Tomohiro; Hanamuro, Takahiro; et al.

JAEA-Research 2011-023, 113 Pages, 2011/10

JAEA-Research-2011-023.pdf:10.9MB

This annual report documents the progress of R&D in the first fiscal year during the JAEA 2nd Midterm Plan (FY 2010 - 2014) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planed framework is structured into the following categories: (1) development and systematization of investigation techniques for selecting suitable sites in geosphere stability, (2) development, application and verification of prediction models for evaluating the changes of geological environment in thermal, hydraulic, mechanical and geochemical conditions for a long period of time, and (3) development of new dating techniques for providing information about geologic history and the timing of geologic events. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.

Journal Articles

Radiochemical study of sub-barrier fusion hindrance in the $$^{19}$$F+$$^{209}$$Bi reaction

Nishinaka, Ichiro; Kasamatsu, Yoshitaka*; Tanikawa, Masashi*; Goto, Shinichi*; Asai, Masato

Proceedings in Radiochemistry, 1(1), p.117 - 121, 2011/09

Unexpected steep falloff of fusion cross sections has recently been observed in heavy-ion fusion reactions at deep sub-barrier energies. In this study the fusion-fission cross sections for $$^{19}$$F+$$^{209}$$Bi at sub-barrier energies were determined by a radiochemical method in order to study sub-barrier fusion hindrance. We will discuss the sub-barrier fusion hindrance in heavy-mass systems, comparing the theoretical calculations and the systematics.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste; Scientific programme for fiscal years 2011

Yasue, Kenichi; Asamori, Koichi; Kusano, Tomohiro; Kokubu, Yoko; Tanikawa, Shinichi; Niwa, Masakazu; Hanamuro, Takahiro; Yamasaki, Seiko; Yamada, Kunimi; Ishimaru, Tsuneari; et al.

JAEA-Review 2011-023, 43 Pages, 2011/07

JAEA-Review-2011-023.pdf:1.84MB

The concept of geological disposal of HLW in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is a plan of research and development (R&D) for geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2011. The objectives and contents in fiscal year 2011 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

JAEA Reports

Research on geosphere stability for long-term isolation of radioactive waste (Progress report for fiscal years 2005 - 2009: H22 report)

Kusano, Tomohiro; Asamori, Koichi; Kurosawa, Hideki; Kokubu, Yoko; Tanikawa, Shinichi; Negi, Tateyuki; Hanamuro, Takahiro; Yasue, Kenichi; Yamasaki, Seiko; Yamada, Kunimi; et al.

JAEA-Research 2010-044, 153 Pages, 2011/01

JAEA-Research-2010-044.pdf:12.53MB

This progress report (H22 report) documents progress made during JAEA 1st Midterm Plan (FY 2005 - 2009) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. For the current 5-year R&D programme, three major goals have been defined as follows: (1) development and synthesis of investigation techniques for selecting suitable sites in geosphere stability, (2) development, application, and evaluation of prediction models for evaluating the changes of geological environment in thermal, hydraulic, mechanical and geochemical conditions for a long period of time, and (3) development of new dating techniques for providing information about geologic history and the timing of geologic events. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.

Journal Articles

Development of methodology to construct a generic conceptual model of river-valley evolution for performance assessment of HLW geological disposal

Kawamura, Makoto*; Tanikawa, Shinichi; Niizato, Tadafumi; Yasue, Kenichi

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.331 - 338, 2010/10

In order to assess the long-term safety of a geological disposal system for high-level radioactive waste (HLW), it is important to consider the impact of uplift and erosion, which cannot be precluded on a timescale in the order of several hundred thousand years for many locations in Japan. Geomorphic evolution, caused by uplift and erosion and coupled to climatic and sea-level changes, will impact the geological disposal system due to resulting spatial and temporal changes in the disposal environment. Degradation of HLW barrier performance will be particularly significant when the remnant repository structures near, and are eventually exposed at, the ground surface. In previous studies, fluvial erosion was identified as the key concern in most settings in Japan. Here, therefore, we present a methodology for development of a generic conceptual model for performance assessment based on best current understanding of fluvial erosion in Japan. Critical considerations that have to be taken into account when interpreting the geological record of past river-valley evolutions, as preserved in ancient fluvial deposits. Interpretation of the impact of such phenomena at relevant locations in Japan has led to development of a generic conceptual model which contains the features typical at middle reach of rivers. This paper presents the methodology to develop the conceptual model, which identifies the simplifications and uncertainties involved and assesses their consequences in the context of repository performance.

JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste; Scientific programme for fiscal years 2010

Yasue, Kenichi; Asamori, Koichi; Yamada, Kunimi; Kokubu, Yoko; Yamasaki, Seiko; Kurosawa, Hideki; Tanikawa, Shinichi; Negi, Tateyuki; Kusano, Tomohiro; Hanamuro, Takahiro; et al.

JAEA-Review 2010-034, 42 Pages, 2010/09

JAEA-Review-2010-034.pdf:1.15MB

The concept of geological disposal of HLW in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is a plan of research and development (R&D) for geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2010. The objectives and contents in fiscal year 2010 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

JAEA Reports

Research on geosphere stability for long-term isolation of radioactive waste; Scientific programme for fiscal years 2010-2014

Umeda, Koji; Ishimaru, Tsuneari; Yasue, Kenichi; Asamori, Koichi; Yamada, Kunimi; Kokubu, Yoko; Hanamuro, Takahiro; Tanikawa, Shinichi; Kusano, Tomohiro

JAEA-Review 2010-030, 48 Pages, 2010/09

JAEA-Review-2010-030.pdf:1.42MB

The concept of geological disposal of HLW in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in a tectonically active zone. This report is to outline 5 years plan (fiscal years 2010-2014) of research and development (R&D) for geosphere stability for long-term isolation of the high-level radioactive waste in JAEA. Background of this research are clarified with the necessity and the significance, and the past progresses in this report. The objectives, outline, contents and schedule during the next 5 years are described in detail. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.

JAEA Reports

Annual report for research on long-term stability of geological environments in FY2008

Kusano, Tomohiro; Asamori, Koichi; Kurosawa, Hideki; Tanikawa, Shinichi; Ninomiya, Atsushi; Negi, Tateyuki; Hanamuro, Takahiro; Yasue, Kenichi; Yamada, Kunimi; Ishimaru, Tsuneari; et al.

JAEA-Research 2009-072, 72 Pages, 2010/03

JAEA-Research-2009-072.pdf:11.27MB

The Japanese islands are located in the tectonically active Circum-Pacific Mobile Belt. As a result, Japan has a high frequency of earthquakes and eruptions. Special consideration is given to the long-term stability of the geological environment, taking into account volcanism, faulting, uplift, denudation, climatic change and sea-level change in Japan. Development of research/prediction technologies for geotectonic events has been carried out to evaluate the long-term stability of the geological environment in Japan. In fiscal year 2008, we carried out the following researches. For studies on faulting and seismic activity, we developed investigation techniques for evolutional history and activity of fault, and carried out case studies for development of effective assessment model in the fault zones. For volcanological and geothermal studies, we provided an integrated approach for detecting crustal magma and/or geothermal fluid in deep underground using geophysical and geochemical data. For the general evaluation study on uplift/denudation and climatic/sea-level change, we arranged investigation techniques for reconstruction of paleo-topography and paleo-climate, and to establish a simulation model for landform development. For studies on the long-term stability of the geological environments, we developed simulation techniques for groundwater flow related by crustal movement.

Journal Articles

Excitation energy dependence of fragment mass and total kinetic energy distributions in proton-induced fission of uranium isotopes

Nishinaka, Ichiro; Tanikawa, Masashi*; Goto, Shinichi*; Nishio, Katsuhisa; Asai, Masato; Tsukada, Kazuaki; Nagame, Yuichiro; Kudo, Hisaaki*

Nuclear Physics A, 805, p.434 - 436, 2008/00

The aim of this work is to study how shell effects of fissioning nuclei and fission fragments are responsible for deformation and mass division during descent from the saddle point to scission. We studied in detail excitation energy dependence of mass and total kinetic energy distributions in the fission of $$p$$ + $$^{233,238}$$U at incident beam energies of 10.0, 11.5 and 13.0 MeV. For the asymmetric mass division in the fission for both uranium isotopes, the obtained yield at $$A$$ $$simeq$$ 132 with the spherical shell of $$N$$ = 82 increases more largely with increasing excitation energy than that at $$A$$ $$simeq$$ 143 with deformed shell of $$N$$ = 86-88. The present excitation energy dependence shows the opposite trend observed in the thermal neutron induced fission and cold fission of actinides. We will discuss the shell effects on excitation energy dependence of fragment mass and total kinetic energy distributions in fission.

Journal Articles

Characteristics of asymmetric mass distribution in proton-induced fission of actinides

Goto, Shinichi*; Kaji, D.*; Nishinaka, Ichiro; Nagame, Yuichiro; Ichikawa, Shinichi; Tsukada, Kazuaki; Asai, Masato; Haba, Hiromitsu; Mitsuoka, Shinichi; Nishio, Katsuhisa; et al.

Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.73 - 76, 2003/01

 Times Cited Count:0 Percentile:0.01(Chemistry, Analytical)

no abstracts in English

Journal Articles

Primary fragment mass-yield distributions for asymmetric fission path of heavy nuclei

Zhao, Y. L.*; Nishinaka, Ichiro; Nagame, Yuichiro; Tsukada, Kazuaki; Sueki, Keisuke*; Goto, Shinichi*; Tanikawa, Masashi*; Nakahara, Hiromichi*

Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.67 - 72, 2003/01

 Times Cited Count:4 Percentile:31.71(Chemistry, Analytical)

no abstracts in English

Journal Articles

Shapes of fragment mass-yield distributions and shapes of scissioning nuclei in actinides

Zhao, Y. L.*; Nagame, Yuichiro; Nishinaka, Ichiro; Tsukada, Kazuaki; Sueki, Keisuke*; Nakahara, Hiromichi*; Goto, Shinichi*; Tanikawa, Masashi*

Journal of Nuclear Science and Technology, 39(Suppl.3), p.30 - 33, 2002/11

no abstracts in English

43 (Records 1-20 displayed on this page)