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Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.
JAEA-Research 2014-030, 457 Pages, 2015/03
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Hayano, Akira; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.
JAEA-Research 2013-037, 455 Pages, 2013/12
Following FY2011, JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, the tree diagram of methodology of groundwater travel time has been extended for crystalline rock, in addition, tree diagram for sedimentary rock newly has been organized. With regard to (2) study on scenario development, the existing approach has been improved in terms of a practical task, and applied and tested for near field focusing on the buffer. In addition, the uncertainty of some important processes and its impact on safety functions are discussed though analysis. With regard to (3) study on setting radionuclide migration parameters, the approaches for parameter setting have been developed for sorption for rocks and solubility, and applied and tested through parameter setting exercises for key radionuclides.
Kasada, Ryuta*; Goto, Takuya*; Fujioka, Shinsuke*; Hiwatari, Ryoji*; Oyama, Naoyuki; Tanigawa, Hiroyasu; Miyazawa, Junichi*; Young Scientists Special Interest Group on Fusion Reactor Realization*
Purazuma, Kaku Yugo Gakkai-Shi, 89(4), p.193 - 198, 2013/04
Japanese young researchers who have interest in realizing fusion reactor have analyzed Technology Readiness Levels (TRL) in Young Scientists Special Interest Group on Fusion Reactor Realization. In this report, brief introduction to TRL assessment and a view of TRL assessment against fusion reactor projects conducting in Japan.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.
JAEA-Research 2012-032, 298 Pages, 2012/09
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.
Harada, Hideo; Goko, Shinji*; Kimura, Atsushi; Ota, Masayuki*; Oshima, Masumi; Kitatani, Fumito; Toh, Yosuke; Furutaka, Kazuyoshi; Kin, Tadahiro; Koizumi, Mitsuo; et al.
Journal of the Korean Physical Society, 59(2), p.1547 - 1552, 2011/08
Times Cited Count:9 Percentile:53.56(Physics, Multidisciplinary)For the improvement of the accuracy on the neutron capture cross sections, a 4 Ge spectrometer was developed. The 4 Ge spectrometer is a unique tool due to its superior energy resolution for studying properties on neutron capture reactions, not only capture cross sections but also resonance identification, -ray intensity distribution, and spin-parity assignment. For example, its performance on the resonance identification was demonstrated using a Ag sample. On the measurement of a -ray intensity distribution for each resonance, the results of U will be shown. Using the 4 Ge spectrometer, the measurements of neutron capture cross sections were started at the J-PARC/MLF/ANNRI. The preliminary results on the measurements of neutron capture cross sections will be discussed mainly based on measurements of neutron capture cross sections for Am, together with related techniques.
Oshima, Masumi; Hori, Junichi*; Harada, Hideo; Furutaka, Kazuyoshi; Koizumi, Mitsuo; Kitatani, Fumito; Toh, Yosuke; Kimura, Atsushi; Nakamura, Shoji; Igashira, Masayuki; et al.
Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.603 - 606, 2008/05
Neutron capture cross sections of minor actinides and long-lived fission products are important for the R&D of innovative nuclear reactors. However, those data are rather poor both in quality and in quantity at present. Thus, we have started projects for neutron cross section measurements. We will construct an innovative -ray spectrometer consisting of Ge crystals and BGO shields. The neutron cross section measurements will be done at KUR linac and JAEA JRR-3M facilities, which will be extended at the high-intensity neutron source at J-PARC.
Koizumi, Mitsuo; Osa, Akihiko; Toh, Yosuke; Kimura, Atsushi; Mizumoto, Motoharu; Oshima, Masumi; Igashira, Masayuki*; Osaki, Toshiro*; Harada, Hideo*; Furutaka, Kazuyoshi*; et al.
Nuclear Instruments and Methods in Physics Research A, 562(2), p.767 - 770, 2006/06
Times Cited Count:6 Percentile:43.77(Instruments & Instrumentation)In order to measure the neutron capture cross section of minor actinides, we have proposed the use of a 4 Ge spectrometer. A Time-of-Flight neutron beam line for the experiment has been constructed at the KURRI electron LINAC. The assembling of the 4 Ge spectrometer is in progress. We are also developing a new data acquisition system based on a digital processing technique.
Koizumi, Mitsuo; Toh, Yosuke; Osa, Akihiko; Kimura, Atsushi; Utsuno, Yutaka; Oshima, Masumi; Hayakawa, Takehito; Hatsukawa, Yuichi; Katakura, Junichi; Matsuda, Makoto; et al.
Proceedings of the International Workshop on Quark Nuclear Physics 2006, p.245 - 252, 2006/00
no abstracts in English
Hirohata, Yuko*; Shibahara, Takahiro*; Tanabe, Tetsuo*; Oya, Yasuhisa*; Arai, Takashi; Goto, Yoshitaka*; Masaki, Kei; Yagyu, Junichi; Oyaizu, Makoto*; Okuno, Kenji*; et al.
Fusion Science and Technology, 48(1), p.557 - 560, 2005/07
Times Cited Count:3 Percentile:24.17(Nuclear Science & Technology)no abstracts in English
Hirohata, Yuko*; Shibahara, Takahiro*; Tanabe, Tetsuo*; Arai, Takashi; Goto, Yoshitaka*; Oya, Yasuhisa*; Yoshida, Hajime*; Morimoto, Yasutomi*; Yagyu, Junichi; Masaki, Kei; et al.
Journal of Nuclear Materials, 337-339, p.609 - 613, 2005/03
Times Cited Count:13 Percentile:65.32(Materials Science, Multidisciplinary)no abstracts in English
Masaki, Kei; Yagyu, Junichi; Miyo, Yasuhiko; Goto, Yoshitaka*; Arai, Takashi; Hayashi, Takao; Kodama, Kozo; Sasajima, Tadayuki; Kaminaga, Atsushi; Tanabe, Tetsuo*; et al.
Journal of Nuclear Materials, 329-333(Part1), p.845 - 848, 2004/08
Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)no abstracts in English
Goto, Yoshitaka*; Arai, Takashi; Yagyu, Junichi; Masaki, Kei; Kodama, Kozo; Miya, Naoyuki
Journal of Nuclear Materials, 329-333(1), p.840 - 844, 2004/08
Times Cited Count:15 Percentile:68.16(Materials Science, Multidisciplinary)TEM and Selected Area Diffraction (SAD) were made on nm-structures of redeposition layers on graphite tiles used in the lower-X-point divertor of JT-60. The tiles were used in the 1988 experimental campaign in which 300 divertor discharges and 1500 limiter discharges were made. TEM observations were made at poloidal and/or toroidal sections at two positions on the inboard side of the inner-separatrix strike point. Layer structures in 0-6micron depths were correlated to the last 40-shots in the campaign. Columnar structures corresponded to divertor discharges of additional heating power below 10MW. Lamellar structures were due to limiter discharges or to the higher power divertor discharges. Carbon-Mo, Ti or carbon-Ni, Fe, Cr, Ti codeposition layers were ascribed to disruptive shots. From analyses on poloidal orientation of the column axes and graphene sheets composing columns, the observed columnar structures were ascribed to both low adatom-migration due to the low deposition temperatures and also to self-shadowing effects due to inclined incidence of carbon impurity ions.
Oya, Yasuhisa*; Morimoto, Yasutomi*; Oyaizu, Makoto*; Hirohata, Yuko*; Yagyu, Junichi; Miyo, Yasuhiko; Goto, Yoshitaka*; Sugiyama, Kazuyoshi*; Okuno, Kenji*; Miya, Naoyuki; et al.
Physica Scripta, T108, p.57 - 62, 2004/00
no abstracts in English
Goto, Junichi; Hama, Katsuhiro
JNC TN5510 2003-002, 18 Pages, 2003/10
The Horonobe Underground Research Laboratory Project is an investigation project which is planned over 20 years. The investigations are conducted in three phases: investigations from the surface (PhaseI), investigations during construction of the underground facility (Phases2) and investigations using the facility (Phase3). Taking into account the results from the Second Progress Report on Research and Development for the Geological Disposal of HLW in Japan, research and development goals for the Horonobe URL project were re-defined.
Kumazaki, Naoki; Koki, Ikeda; Goto, Junichi; Mukai, Kei; Iwatsuki, Teruki; Furue, Ryoji
JNC TN7400 2003-005, 112 Pages, 2003/08
The Shallow Borehole Investigations were one of the first programmes to be conducted at the MIU Construction Site, together with the reflection seismic survey and the re-investigation of borehole DH-2. The Shallow Borehole Investigation targeted the shallow part of the site, from the sedimentary cover rocks to the upper part of the granite. The main aims are understanding of initial groundwater flow and the groundwater chemistry, long term monitoring and to identify structural discontinuities in the sedimentary rocks and the weathered granite. From April to October 2002 four boreholes were drilled through the sedimentary sequence and the weathered granite section at the MIU Construction Site. Planned geological, hydrogeological and hydrochemical investigations were carried out. MP systems were installed in all boreholes by December 2002 and continuous monitoring of hydraulic head begun. Information on geology, hydrogeology and hydrochemistry of the sedimentary formation and the weathered granite was acquired. JNC's quality control procedures for borehole investigation programmes were employed. In addition, recommendations for future borehole investigation programmes, especially in sedimentary rocks, were given.
Goto, Junichi; Hama, Katsuhiro
JNC TN5510 2003-001, 19 Pages, 2003/08
The Horonobe Underground Research Laboratory Project is an investigation project which is planned over 20 years. The investigations are conducted in the three phases, investigations from surface (Phase 1), investigations during construction of the underground facility (Phase 2) and investigations using the facility (Phase 3). The 2003 fiscal year is the fourth year of the Phase 1 surface-based investigations.In the development of techniques to investigate the geological environment, geophysical, geological, surface hydrogeological and borehole investigations are carried out. Models of geological environment are constructed and revised based on the acquired data. In the development of monitoring techniques of the geological environment, long-term monitoring of groundwater pressure is continued in the previously equipped borehole. The long-term monitoring systems are also installed in the remaining boreholes, and measurement is subsequently started. Development of the remotely operated monitoring system (ACROSS) is continued. In the study on long-term stability of the geological environment, monitoring with seismographs, GPS and electromagnetic survey equipment is carried out. In the development of basis for engineering techniques in deep underground, basic design of the underground facility is defined. In the research and development on geological disposal, laboratory tests are continued on the transportation and emplacement equipment of engineered barrier, and on the reinforcement material to make detailed plans of the Phase 2 and 3 investigations. In the improvement of reliability on safety assessment methods, suitability of safety assessment methods is examined using the field and laboratory data. Design of the facility on the ground is defined, and development of the site for the underground laboratory is started. In the environmental survey, environmental monitoring is continued. Cooperation with domestic and overseas research institutes is proceeded.
Oya, Yasuhisa*; Hirohata, Yuko*; Morimoto, Yasutomi*; Yoshida, Hajime*; Kodama, Hiroshi*; Kizu, Kaname; Yagyu, Junichi; Goto, Yoshitaka*; Masaki, Kei; Okuno, Kenji*; et al.
Journal of Nuclear Materials, 313-316, p.209 - 213, 2003/03
Times Cited Count:25 Percentile:82.86(Materials Science, Multidisciplinary)no abstracts in English
Goto, Yoshitaka*; Yagyu, Junichi; Masaki, Kei; Kizu, Kaname; Kaminaga, Atsushi; Kodama, Kozo; Arai, Takashi; Tanabe, Tetsuo*; Miya, Naoyuki
Journal of Nuclear Materials, 313-316, p.370 - 376, 2003/03
Times Cited Count:46 Percentile:92.95(Materials Science, Multidisciplinary)Erosion and re-deposition were studied for graphite tiles from W-shaped divertor region of JT-60U in Jun. 1997 - Oct. 1998 periods in which more than 3000 D-D discharges were made with all-carbon wall with boronizations and inner-private flux pumping. On the outer divertor targets, erosion was dominant: maximum erosion depth of around 20 micrometers was measured, while on the inner targets, re-deposition was dominant: columnar structure layers and laminar/columnar-layered structures of maximum thickness around 60 micrometers were found. Through XPS analysis, compositions of the re-deposition layers at a around mid point on the inner target were 94 - 95 at% C, 3 - 4 at% B, and less than 0.6 at% O, Fe, Cr, and Ni. Boron is mainly bound to Carbon. No continuous deposition layers on the dome top/outer wing, while deposition layers were found on the inner wing. Observed in/out asymmetry is attributable to in/out asymmetry of plasma particle conditions in the divertor region.
Yagyu, Junichi; Goto, Yoshitaka*; Arai, Takashi; Miya, Naoyuki; Morimoto, Yasutomi*; Okuno, Kenji*; Oya, Yasuhisa*; Hirohata, Yuko*; Tanabe, Tetsuo*
Heisei-15-Nendo Kiki, Bunseki Gijutsu Kenkyukai Hokoku, p.105 - 108, 2003/00
no abstracts in English
Miyo, Yasuhiko; Goto, Yoshitaka*; Yagyu, Junichi; Masaki, Kei; Miya, Naoyuki
Heisei-15-Nendo Kiki, Bunseki Gijutsu Kenkyukai Hokoku, p.117 - 120, 2003/00
no abstracts in English