Yasuda, Satoshi; Tamura, Kazuhisa; Terasawa, Tomoo; Yano, Masahiro; Nakajima, Hideaki*; Morimoto, Takahiro*; Okazaki, Toshiya*; Agari, Ryushi*; Takahashi, Yasufumi*; Kato, Masaru*; et al.
Journal of Physical Chemistry C, 124(9), p.5300 - 5307, 2020/03
Confinement of hydrogen molecules at graphene-substrate interface has presented significant importance from the viewpoints of development of fundamental understanding of two-dimensional material interface and energy storage system. In this study, we investigate H confinement at a graphene-Au interface by combining selective proton permeability of graphene and the electrochemical hydrogen evolution reaction (electrochemical HER) method. After HER on a graphene/Au electrode in protonic acidic solution, scanning tunneling microscopy finds that H nanobubble structures can be produced between graphene and the Au surface. Strain analysis by Raman spectroscopy also shows that atomic size roughness on the graphene/Au surface originating from the HER-induced strain relaxation of graphene plays significant role in formation of the nucleation site and H storage capacity.
Kimura, Atsushi; Nakamura, Shoji; Terada, Kazushi*; Nakao, Taro*; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 56(6), p.479 - 492, 2019/06
Terada, Kazushi*; Kimura, Atsushi; Nakao, Taro*; Nakamura, Shoji; Mizuyama, Kazuhito*; Iwamoto, Nobuyuki; Iwamoto, Osamu; Harada, Hideo; Katabuchi, Tatsuya*; Igashira, Masayuki*; et al.
Journal of Nuclear Science and Technology, 55(10), p.1198 - 1211, 2018/10
Sugita, Yutaka; Aoyagi, Kazuhei; Kubota, Kenji*; Nakata, Eiji*; Oyama, Takahiro*
JAEA-Research 2018-002, 72 Pages, 2018/06
In a excavation of shafts and galleries in the deep underground for disposing radioactive waste, an excavation damaged zone (EDZ) is developed around the galleries and shafts owing to the stress redistribution. Since the characteristic changes of the rock mass in the EDZ affects the radionuclides migration behavior, it is important to understand the long-term behavior of the EDZ. Thus, we performed the in situ experiment to investigate the long-term behavior of EDZ as part of the collaborative research between Japan Atomic Energy Agency and Central Research Institute of Electric Power Industry in the 140m gallery in the Horonobe Underground Research Laboratory. In this research, we investigated the extent, mechanism of the change of hydro-mechanical characteristic, and long-term behavior of the EDZ on the basis of the comprehensive estimation of the results of the observation of the drift wall and the various investigations using boreholes such as geological investigation, the seismic and resistivity tomography, hydraulic test, water content monitoring, borehole loading test, convergence measurement, and so on. In addition, we clarified applicability and future tasks of the testing method used in this research for the investigation of the long-term behavior of the EDZ.
Muramatsu, Toshiharu; Aoyagi, Yuji*; Yoshiuji, Takahiro*
Nihon Kikai Gakkai 2017-Nendo Nenji Taikai Koen Rombunshu (DVD-ROM), 4 Pages, 2017/09
A general-purpose three-dimensional thermohydraulics numerical simulation code SPLICE was developed at Japan Atomic Energy Agency and designed to deal with gas-liquid-solid consolidated incompressible viscous flows with a phase change process in various laser applications, such as welding, coating, cutting, etc. The result obtained from metal powder laser additive manufacturing simulations is very encouraging in the sense that the SPLICE code would be used as one of efficient tools to provide the laser irradiation conditions.
Iwamoto, Hiroki; Nishihara, Kenji; Yagi, Takahiro*; Pyeon, C.-H.*
Journal of Nuclear Science and Technology, 54(4), p.432 - 443, 2017/04
Sato, Toshinori; Sasamoto, Hiroshi; Ishii, Eiichi; Matsuoka, Toshiyuki; Hayano, Akira; Miyakawa, Kazuya; Fujita, Tomoo*; Tanai, Kenji; Nakayama, Masashi; Takeda, Masaki; et al.
JAEA-Research 2016-025, 313 Pages, 2017/03
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. This report summarizes the results of the Phase II investigations carried out from April 2005 to June 2014 to a depth of 350m. Integration of work from different disciplines into a "geosynthesis" ensures that the Phase II goals have been successfully achieved and identifies key issues that need to made to be addressed in the Phase II investigations Efforts are made to summarize as many lessons learnt from the Phase II investigations and other technical achievements as possible to form a "knowledge base" that will reinforce the technical basis for both implementation and the formulation of safety regulations.
Takahashi, Yoshiyuki*; Hori, Junichi*; Sano, Tadafumi*; Yagi, Takahiro*; Yashima, Hiroshi*; Pyeon, C. H.*; Nakamura, Shoji; Harada, Hideo
Proceedings of International Conference on the Physics of Reactors; Unifying Theory and Experiments in the 21st Century (PHYSOR 2016) (USB Flash Drive), p.645 - 652, 2016/05
For the reduction of radioactive toxicities, feasibility study of nuclear transmutation of minor actinides (MAs) and long-lived fission products (LLFPs) by utilizing innovative nuclear reactor system (i.e. fast breeder reactors and accelerator-driven systems) has been actively conducted. To design these nuclear reactor systems, the accurate nuclear data are required. Therefore, to obtain more accurate nuclear data, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides(AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program". In a part of this project, the nuclear data of MAs are verified in the variable neutron spectra field at Kyoto University Research Reactor Institute-LINear ACcelerator (KURRI-LINAC) and Kyoto University Critical Assembly (KUCA). And the differential TOF data is cross-checked with an integral data for the validation of Np, Am, and Am. In this summary, the results of reaction rate of neutron capture cross section of Np are reported as an example in the study.
Pyeon, C. H.*; Fujimoto, Atsushi*; Sugawara, Takanori; Yagi, Takahiro*; Iwamoto, Hiroki; Nishihara, Kenji; Takahashi, Yoshiyuki*; Nakajima, Ken*; Tsujimoto, Kazufumi
Journal of Nuclear Science and Technology, 53(4), p.602 - 612, 2016/04
Sample reactivity experiments on the uncertainty analyses of Pb nuclear data are carried out by substituting Al plates for Pb ones at the Kyoto University Critical Assembly, as part of basic research on Pb-Bi for the coolant. Numerical simulations of sample reactivity experiments are performed with the Monte Carlo calculation code MCNP6.1 together with four nuclear data libraries JENDL-3.3, JENDL-4.0, ENDF/B-VII.0 and JEFF-3.1, to examine the accuracy of cross-section uncertainties of Pb isotopes by comparing measured and calculated sample reactivities. A library update from JENDL-3.3 to JENDL-4.0 is demonstrated by the fact that the difference between Pb isotopes of the two JENDL libraries is dominant in the comparative study, through the experimental analyses of sample reactivity by the MCNP approach. In addition, JENDL-4.0 reveals a slight difference from ENDF/B-VII.0 in all Pb isotopes and Al, and from JEFF-3.1 in U and Al.
Harada, Hideo; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Terada, Kazushi; Nakao, Taro; Nakamura, Shoji; Mizuyama, Kazuhito; Igashira, Masayuki*; Katabuchi, Tatsuya*; et al.
EPJ Web of Conferences, 93, p.06001_1 - 06001_5, 2015/05
Improvement of accuracy of neutron nuclear data for minor actinides (MAs) and long-lived fission products (LLFPs) is required for developing innovative nuclear system transmuting these nuclei. In order to meet the requirement, the project entitled as "Research and development for Accuracy Improvement of neutron nuclear data on Minor ACtinides (AIMAC)" has been started as one of the "Innovative Nuclear Research and Development Program" at October 2013. The AIMAC project team is composed of researchers in four different fields: differential nuclear data measurement, integral nuclear data measurement, nuclear chemistry, and nuclear data evaluation. By integrating all of the forefront knowledge and techniques in these fields, the team aims at improving the accuracy of the data. The background, overall plan, and recent progress of the AIMAC project will be reviewed.
Sugawara, Takanori; Oizumi, Akito; Kitamura, Yasunori; Iwamoto, Hiroki; Yagi, Takahiro*; Pyeon, C. H.*
KURRI Progress Report 2013, 1 Pages, 2014/10
The Japan Atomic Energy Agency (JAEA) has investigated the accelerator-driven system (ADS) to transmute minor actinides discharged from nuclear power plants. The ADS investigated by JAEA is a lead bismuth eutectic (LBE) cooled-tank-type ADS. It has been known that there was a major upgrade for the cross section data of lead isotopes from JENDL-3.3 to JENDL-4.0. Due to this upgrade, the value of of the core was significantly changed, from 0.97 calculated by JENDL-3.3 to 1.00 calculated by JENDL-4.0. The difference was mainly caused by the cross section data of the lead isotopes from JENDL-3.3 to JENDL-4.0. This study aims to measure sample worth reactivity from aluminum plates to lead or LBE ones to validate the nuclear data of lead and bismuth isotopes.
Sugawara, Takanori; Nishihara, Kenji; Iwamoto, Hiroki; Yagi, Takahiro*; Pyeon, C. H.*
KURRI Progress Report 2012, P. 212, 2013/10
An Accelerator-Driven System (ADS) has been investigated in Japan Atomic Energy Agency (JAEA) to transmute minor actinides discharged from nuclear power plants. The ADS proposed by JAEA is a lead bismuth eutectic (LBE) cooled-tank-type ADS. It has been known that there was a major upgrade for the cross section data of lead isotopes from JENDL-3.3 to JENDL-4.0 and the upgrade affects to the neutronic design of the ADS. This study aims to measure replacement reactivity from aluminum plates to lead plates at KUCA (Kyoto University Critical Assembly) to know which nuclear data library, JENDL-3.3 or JENDL-4.0 is reasonable for the lead isotopes. As the result, the replacement reactivity from the aluminum plates to the lead ones was measured as the positive value and the calculation results indicated that the lead nuclear data in JENDL-4.0 might be more reasonable than those in JENDL-3.3.
Nishihara, Kenji; Sugawara, Takanori; Iwamoto, Hiroki; Pyeon, C. H.*; Yagi, Takahiro*
KURRI Progress Report 2011, P. 221, 2012/10
The maximum likelihood analysis method for pulse neutron source experiment (PNS-ML) has been developed in experiments using KUCA to monitor sub-criticality of an accelerator-driven system (ADS). In this technique, the most likely sub-criticality can be deduced from a series of counted data from a detector. In the present study, both sub-criticality and neutron generation time are deduced from the same counted data.
Sano, Asami; Kuribayashi, Takahiro*; Komatsu, Kazuki*; Yagi, Takehiko*; Otani, Eiji*
Physics of the Earth and Planetary Interiors, 189(1-2), p.56 - 62, 2011/11
A neutron powder diffraction experiment was conducted to refine the hydrogen position of Mg-endmember deuterated wadsleyite. Preliminary refinement using the dry-structure determined by single crystal X-ray diffraction reveals a maximum peak Q1 of nuclear density in the difference Fourier map at the M3 octahedral edge, between the O1 and O4 atoms. Full Rietveld refinement was conducted assuming that the maximum peak corresponds to deuterium atom. The deuterium position was determined as (0.096, 0.289, 0.315) with occupancy of 8.2%. The structure determined by this study predicts that the hydration of wadsleyite has an anisotropic effect on diffusion properties.
Kondo, Keitaro; Yagi, Takahiro*; Ochiai, Kentaro; Sato, Satoshi; Takakura, Kosuke; Onishi, Seiki; Konno, Chikara
Fusion Engineering and Design, 86(9-11), p.2184 - 2187, 2011/10
In the neutronics experiment for the ITER test blanket module with a Li-enriched LiTiO layer and a beryllium layer conducted at the FNS facility of Japan Atomic Energy Agency, the calculated tritium production rate (TPR) was by approximately 10% larger than the measured one only when a neutron source reflector composed of SS316 was attached. On the other hand, the influence of the reflector on the TPR prediction accuracy was not seen in the recent blanket experiment with a natural LiTiO layer, beryllium layers and the reflector. We investigated the former experiment in detail, and found an unphysical tendency in the measured TPR distribution. In order to clarify whether the deterioration of the TPR prediction accuracy originates from the reflector or not, we have conducted the same experiment as the previous experiment again. In the present experiment, the measured TPR distribution inside the Li-enriched LiTiO layer well agreed with the calculated one within an estimated experimental error of 6%. We conclude that the overestimation of TPR observed in the previous experiment would be due to some experimental errors and that the TPR prediction accuracy is good even in the case with the reflector.
Ochiai, Kentaro; Kondo, Keitaro; Onishi, Seiki; Takakura, Kosuke; Sato, Satoshi; Abe, Yuichi; Konno, Chikara; Suzuki, Chihiro*; Yagi, Takahiro*
Journal of the Korean Physical Society, 59(2), p.1953 - 1956, 2011/08
Lead is an important candidate material as multiplier of nuclear fusion reactor. Few DT neutron integral benchmark experiments were performed for lead so far. Therefore, we have carried out an integral benchmark experiment on lead at the DT neutron source facility of JAEA, FNS. A cubic lead assembly on a side of 45.3 cm was set up and was irradiated with the DT neutron source. Reaction rates of the Al(n,)Na, Nb(n,2n)Nb, Zr(n,2n)Zr and In(n,n')In reactions were measured as fast neutron spectrum indices in the assembly. A small NE213 spectrometer was also used for measurement of neutron spectra in the assembly. A Monte Carlo calculation code, MCNP5, was adopted to calculate the above neutron spectra and activation reaction rates. Nuclear data libraries, JENDL-3.3, ENDF/B-VII.0, JEFF-3.1 and FENDL-2.1, were used in the calculation. The calculation results of the three libraries except for JENDL-3.3 agreed with the measuring ones. In case of JENDL-3.3, some remarkable disagreements were found. From our investigations, it was pointed out that the inappropriate evaluation of the (n,2n) and inelastic cross sections of lead in JENDL-3.3 caused such disagreement.
Kondo, Keitaro; Ochiai, Kentaro; Tatebe, Yosuke; Yagi, Takahiro; Onishi, Seiki; Takakura, Kosuke; Sato, Satoshi; Konno, Chikara
Progress in Nuclear Science and Technology (Internet), 1, p.61 - 64, 2011/02
At the Fusion Neutronics Source (FNS) facility of JAEA we have conducted various integral experiments with DT neutrons for fusion reactor materials and have made a significant progress in the verification of their nuclear data. Recently we started a new series of integral experiments with DD neutrons at FNS in order to verify nuclear data relating to DD neutrons effectively. An integral experiment on beryllium with the DD neutron source will be presented in this conference. A beryllium pseudo-cylinder assembly of 45 cm in thickness and 63 cm in the diameter was built at the distance of 20 cm from the DD neutron source, and reaction rates of the In(n,n')In, Au(n,)Au and Li(n,)T reactions and a U fission rate were measured. The measured values were compared with calculations with the MCNP5 code and the latest nuclear data libraries; JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. A slight disagreement between the measurement and the calculation was found in the reaction rate of In, which is sensitive to neutrons above 0.3 MeV. We identified that the disagreement originated from the angular differential cross section data of the elastic scattering around 3 MeV and from the (n,2n) reaction cross section data near its threshold energy. The calculated reaction rates of Au, Li and U, which are sensitive to low energy neutrons, showed a large overestimation, which also appeared at the beryllium integral experiment with DT neutrons previously carried out at FNS. This problem has not been solved yet.
Isayama, Akihiko; Sakakibara, Satoru*; Furukawa, Masaru*; Matsunaga, Go; Yamazaki, Kozo*; Watanabe, Kiyomasa*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; Tamura, Naoki*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 86(6), p.374 - 377, 2010/06
no abstracts in English
Igarashi, Takahiro; Aoyagi, Yoshiteru; Kaji, Yoshiyuki
Proceedings of 18th International Conference on Nuclear Engineering (ICONE-18) (CD-ROM), 5 Pages, 2010/05
no abstracts in English
Osakabe, Masaki*; Shinohara, Koji; Toi, Kazuo*; Todo, Yasushi*; Hamamatsu, Kiyotaka; Murakami, Sadayoshi*; Yamamoto, Satoshi*; Idomura, Yasuhiro; Sakamoto, Yoshiteru; Tanaka, Kenji*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 85(12), p.839 - 842, 2009/12
no abstracts in English