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JAEA Reports

Research plan on geosphere stability for long-term isolation of radioactive waste (Scientific program for fiscal year 2019)

Ishimaru, Tsuneari; Ogata, Nobuhisa; Hanamuro, Takahiro; Shimada, Akiomi; Kokubu, Yoko; Asamori, Koichi; Niwa, Masakazu; Shimada, Koji; Watanabe, Takahiro; Sueoka, Shigeru; et al.

JAEA-Review 2019-010, 46 Pages, 2019/09

JAEA-Review-2019-010.pdf:2.45MB

This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in Japan Atomic Energy Agency, in fiscal year 2019. The objectives and contents in fiscal year 2019 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. 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.

Journal Articles

Diagrams for finite strain equations and rough estimation of shear strain

Shimada, Koji

Chishitsu Gijutsu, (9), p.25 - 40, 2019/09

Today many collaborations are there in Earth-scientific research and development. Structural geology can serve crucial information on tectonic strain at sampling point in Japan, belonging to the circum-Pacific orogenic belt. Visualize of strain estimation would be effective during field geological survey and for better understanding for non-specialist on structural geology. Illustrations decoding mathematical expressions of strain estimation methods are presented here.

Journal Articles

Formation age and cooling history of Kojaku granite

Sueoka, Shigeru; Shimada, Koji; Ishimaru, Tsuneari; Danhara, Toru*; Iwano, Hideki*; Yagi, Koshi*

Chigaku Zasshi, 127(6), p.795 - 803, 2018/12

no abstracts in English

Journal Articles

Examination of evaluation method for fault activity based on morphological observation of fault planes

Tanaka, Yoshihiro*; Kametaka, Masao*; Okazaki, Kazuhiko*; Suzuki, Kazushige*; Seshimo, Kazuyoshi; Aoki, Kazuhiro; Shimada, Koji; Watanabe, Takahiro; Nakayama, Kazuhiko

Oyo Chishitsu, 59(1), p.13 - 27, 2018/04

This paper aims to develop a methodology for understanding the fault activity by observing exposed fault planes without covering younger strata. Based on purpose, faults developed in relatively homogeneous rocks such granitic types are investigated as follows; Gosuke Dam upstream outcrop of Gosukebashi Fault and Funasaka-nishi outcrop of Rokkou Fault were selected for the study of an active fault; and K-3 outcrop of Rokkou Houraikyo Fault was chosen for a non-active fault.

JAEA Reports

Database of granite crack in northwestern Tsuruga Peninsula

Terusawa, Shuji; Shimada, Koji

JAEA-Data/Code 2017-017, 18 Pages, 2018/03

JAEA-Data-Code-2017-017.pdf:5.14MB
JAEA-Data-Code-2017-017-appendix(CD-ROM).zip:0.44MB

Cracks (joints, fracture zones, etc.) are formed in granite by various mechanisms. Faulting uses these pre-existing cracks as weak plane. In addition, there may be directionality in the direction of the crack, producing a linear valley. Attempts are also being made to estimate a regional stress field from the direction of excellence. In this paper, we developed a database of cracks in granite by compiling 5050 points of strike-dip data, as part of the geologic surveys of the Monju fast-breeder reactor located in the northwestern part of the Tsuruga Peninsula. The strike-dip is predominantly northern northeast to northeast strike and high angle east dip, but shows different characteristics for each place. Therefore, further analysis using this database is desired.

Journal Articles

Fission track dating of faulting events accommodating plastic deformation of biotites

Sueoka, Shigeru; Shimada, Koji; Ishimaru, Tsuneari; Niwa, Masakazu; Yasue, Kenichi; Umeda, Koji*; Danhara, Toru*; Iwano, Hideki*

Journal of Geophysical Research; Solid Earth, 122(3), p.1848 - 1859, 2017/03

no abstracts in English

Journal Articles

Dating of crush zones associated with plastic deformation of biotite; Constraints by fission-track thermochronometry

Sueoka, Shigeru; Shimada, Koji; Ishimaru, Tsuneari; Niwa, Masakazu; Yasue, Kenichi; Umeda, Koji*; Danhara, Toru*; Iwano, Hideki*

Fisshion, Torakku Nyusureta, (29), p.5 - 7, 2016/12

no abstracts in English

JAEA Reports

Observed and analyzed data for clay veins in granite

Ueki, Tadamasa; Tanabe, Hiroaki*; Niwa, Masakazu; Ishimaru, Tsuneari; Shimada, Koji

JAEA-Data/Code 2016-010, 292 Pages, 2016/09

JAEA-Data-Code-2016-010.pdf:76.12MB

Occurrence of recent activity of faults is often evaluated based on displacements of subsurface sediments covering the faults. However, this evaluation is not applicable for faults that occur where subsurface sediments are not found. In this study, mesoscopic description in a field, microscopic observation using thin sections, chemical composition mapping for polished slabs, X-ray diffraction analysis, particle size distribution analysis, and detailed analysis for quartz fragments (scanning electron microscopy and measurement of electron spin resonance signals) were carried out for clay veins in order to contribute a development of evaluation of fault activity. This Data/Code reports the results of these observation and analyses.

Journal Articles

Microscopic features of quartz and clay particles from fault gouges and infilled fractures in granite; Discriminating between active and inactive faulting

Niwa, Masakazu; Shimada, Koji; Aoki, Kazuhiro; Ishimaru, Tsuneari

Engineering Geology, 210, p.180 - 196, 2016/08

 Times Cited Count:3 Percentile:52.71(Engineering, Geological)

This study focused on microscopic features using particle size analysis, SEM and TEM and identified mineralogical and textural characteristics to improve our ability to discriminate between the active and inactive gouges. Particle size distribution analysis largely shows that fault gouge in an active fault, having the most abundant finer particles, experienced repetitive shearing whereas the inactive gouges did not. SEM examination of quartz particles shows that more particles retain their primary crystal structure in the active gouge than in the inactive gouges. In contrast, observation of very fine clay minerals using TEM shows the minerals in the active gouge are abraded and corroded in equal or higher degree as the aseismic gouges. Repetitive fault activities could result in the addition of new quartz particles from the granite with preservation of primary crystal structure, whereas relatively-soft clay minerals had been affected by abrasion and dissolution.

Journal Articles

Cooling and denudation history of the Tsuruga body of Kojaku granite, southwest Japan, constrained from multi-system thermochronology

Sueoka, Shigeru; Umeda, Koji; Yasue, Kenichi; Niwa, Masakazu; Shimada, Koji; Ishimaru, Tsuneari; Danhara, Toru*; Iwano, Hideki*; Yagi, Koshi*

Chigaku Zasshi, 125(2), p.201 - 219, 2016/04

We applied multi-system thermochronology to the Tsuruga body of the Kojaku granite to constrain the cooling/denudation history of the Tsuruga area. Based on the thermochronometric results and other data, we reconstructed the cooling and denudation histories of the Tsuruga body as below: (1) the Tsuruga body intruded at c.a. 68 Ma at the depth of 4-5 km, (2) rapidly cooled down to c.a. 200$$^{circ}$$C by heat conduction within a few million years or less, and (3) slowly cooled due to peneplanation during the Cenozoic. This cooling/denudation history is consistent with the observations that cataclasite and fault gouge are dominant in the crush zones of the Tsuruga body, that similar slow cooling histories over the Cenozoic are estimated in the surrounding areas based on thermochronometric ages, and that the amount of denudation in the last few million years in the Tsuruga area is inferred at less than several hundred meters from the elevations of the uplifted peneplains.

Journal Articles

Thermal constraints on clay growth in fault gouge and their relationship with fault-zone evolution and hydrothermal alteration; Case study of gouges in the Kojaku Granite, Central Japan

Niwa, Masakazu; Shimada, Koji; Tamura, Hajimu*; Shibata, Kenji*; Sueoka, Shigeru; Yasue, Kenichi; Ishimaru, Tsuneari; Umeda, Koji*

Clays and Clay Minerals, 64(2), p.86 - 107, 2016/04

 Times Cited Count:3 Percentile:65.67(Chemistry, Physical)

no abstracts in English

Journal Articles

Contribution of geoscience to nuclear safety, 2; Mineralogical and geochemical analysis of faulted material for fault activity assessment

Niwa, Masakazu; Ishimaru, Tsuneari; Shimada, Koji

Nippon Genshiryoku Gakkai-Shi, 58(3), p.167 - 171, 2016/03

no abstracts in English

JAEA Reports

Research on geosphere stability for long-term isolation of radioactive waste; Scientific programme for fiscal years 2015-2021

Umeda, Koji; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Fujita, Natsuko; Shimizu, Mayuko; Shimada, Akiomi; Matsubara, Akihiro; Tamura, Hajimu; et al.

JAEA-Review 2015-012, 43 Pages, 2015/08

JAEA-Review-2015-012.pdf:1.24MB

The concept of geological disposal of high-level radioactive waste (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 tectonically active zone. This report is to outline 7 years plan (fiscal years 2015-2021) of research and development (R&D) for geosphere stability for long-term isolation of the HLW in JAEA. Background of this research is clarified with the necessity and the significance, and the past progress in this report. The objectives, outline, contents and schedule during the next 7 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

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 4

Omori, Hiroyuki; Nebashi, Koji; Shimada, Asako; Tanaka, Kiwamu; Yasuda, Mari; Hoshi, Akiko; Tsuji, Tomoyuki; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2014-029, 31 Pages, 2015/03

JAEA-Data-Code-2014-029.pdf:1.51MB

Simple and rapid methods to evaluate the radioactivity concentrations are required for the radioactive waste generated from research facilities in the Japan Atomic Energy Agency to dispose of in a near-surface repository. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid waste generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid waste generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In this report, we reported the analytical data determined in fiscal 2014 ($$^{137}$$Cs and $$^{93}$$Mo) and summarized them with the radioactivity concentrations obtained in the past as basic data to consider the evaluation method of radioactivity concentrations in the stored waste taken from JPDR.

Journal Articles

Development of a rapid analytical method for $$^{129}$$I in the contaminated water and tree samples at the Fukushima Daiichi Nuclear Power Station

Shimada, Asako; Ozawa, Mayumi; Kameo, Yutaka; Yasumatsu, Takuyo*; Nebashi, Koji*; Niiyama, Takuya; Seki, Shuhei; Kajio, Masatoshi; Takahashi, Kuniaki

Nuclear Back-end and Transmutation Technology for Waste Disposal, p.311 - 317, 2015/00

no abstracts in English

JAEA Reports

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

Yasue, Kenichi; Asamori, Koichi; Niwa, Masakazu; Kokubu, Yoko; Kobori, Kazuo; Makuuchi, Ayumu; Matsubara, Akihiro; Shibata, Kenji; Tamura, Hajimu; Tanabe, Hiroaki; et al.

JAEA-Review 2014-033, 43 Pages, 2014/09

JAEA-Review-2014-033.pdf:16.91MB

The concept of geological disposal of HLW in Japan is based on a multi-barrier system which combines a stable geological environment with a robust 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) on geosphere stability for long-term isolation of HLW in JAEA, in fiscal year 2014. The objectives and contents in fiscal year 2014 are described in detail based on the outline of 5 years plan (fiscal years 2010-2014). In addition, the planned 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.

Journal Articles

Ribbon thickness dependence of the magnetic alloy core characteristics in the accelerating frequency region of the J-PARC synchrotrons

Nomura, Masahiro; Shimada, Taihei; Tamura, Fumihiko; Yamamoto, Masanobu; Hara, Keigo*; Hasegawa, Katsushi*; Omori, Chihiro*; Takata, Koji*; Toda, Makoto*; Yoshii, Masahito*; et al.

Nuclear Instruments and Methods in Physics Research A, 749, p.84 - 89, 2014/06

 Times Cited Count:1 Percentile:85.28(Instruments & Instrumentation)

We have been developing high shunt impedance Magnetic Alloy (MA) cores. The MA core shunt impedance is a key parameter to achieve a higher field gradient for increasing a beam power. We increase the MA core shunt impedance by two different ways. One way is applying an external magnetic field during annealing to increase the MA core magnetic properties. The other way is using thinner ribbons to reduce the eddy current. In this paper, we discuss the latter way.

Journal Articles

A Sampling method of oriented small sample from fault cores for SEM observation

Shimada, Koji; Kametaka, Masao*; Nakayama, Kazuhiko; Seshimo, Kazuyoshi; Tanaka, Yoshihiro; Hayashi, Toshio*; Tanaka, Yukumo; Shimogama, Kota*; Okazaki, Kazuhiko*

Chishitsugaku Zasshi, 119(11), p.727 - 731, 2013/11

Staples for a stapler can be used as a frame of a small oriented sample taken from fragile and scarce fault gouge. The fault gouge was slotted for staples of an insert. Staples are a group of about ten or less ones holding right-angled three small surfaces. Pre-oriented staples set the slot would remove then presented for the SEM observation. Only a knife, some glues and simple equipment are needed for the method in the field or laboratories.

Journal Articles

Perpendicular magnetic anisotropy with enhanced orbital moments of Fe adatoms on a topological surface of Bi$$_2$$Se$$_3$$

Ye, M.*; Kuroda, Kenta*; Takeda, Yukiharu; Saito, Yuji; Okamoto, Kazuaki*; Zhu, S.-Y.*; Shirai, Kaito*; Miyamoto, Koji*; Arita, Masashi*; Nakatake, Masashi*; et al.

Journal of Physics; Condensed Matter, 25(23), p.232201_1 - 232201_5, 2013/06

 Times Cited Count:9 Percentile:47.06(Physics, Condensed Matter)

no abstracts in English

JAEA Reports

Mizunami Underground Research Laboratory Project, Plan for fiscal year 2012

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Kuboshima, Koji; Takeuchi, Ryuji; Mizuno, Takashi; Sato, Toshinori; et al.

JAEA-Review 2012-028, 31 Pages, 2012/08

JAEA-Review-2012-028.pdf:3.86MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU project is planned in three overlapping phases; Surface-based Investigation Phase (Phase I), Construction Phase (Phase II) and Operation Phase (Phase III). Currently, the project is under the Construction Phase and the Operation Phase. This document introduces the research and development activities planned for 2012 fiscal year based on the MIU Master Plan updated in 2010, construction plan and research collaboration plan, etc.

153 (Records 1-20 displayed on this page)