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Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Ogawa, Hiroki; Hakoiwa, Hiroaki; Watanabe, Tsuyoshi; Nishiyama, Nariaki; Yokoyama, Tatsunori; Ogata, Manabu; et al.
JAEA-Research 2023-005, 78 Pages, 2023/10
JAEA-Research-2023-005.pdf:6.51MB
This annual report documents the progress of research and development (R&D) in the 1st fiscal year of the Japan Atomic Energy Agency 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. 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. The current status of R&D activities with previous scientific and technological progress is summarized.
Watanabe, Yasuhiro; Yanagibashi, Takanori; Komatsuzaki, Makoto*
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1024 - 1028, 2023/10
J-PARC RCS accelerates a high-intensity proton beam from 400 MeV to 3 GeV at a repetition rate of 25 Hz. The main magnet system of the RCS is composed of a family of dipole magnets and seven families of quadrupole magnets excited by eight independent resonant circuits. The current control system of the main magnet power supply requires high-precision tracking control between different magnet families. The original control system of the main magnet power supply had been operated without major problems for fifteen years since the start of operation of the RCS, while the control system component is obsolete. We developed a new power supply controller based on SoC FPGA. The controller consists of a main board and four daughter boards and all functions required for current control of the power supply are installed in a 19-inch rack 2U control unit.
Wang, Q.*; Ma, N.*; Huang, W.*; Shi, J.*; Luo, X.-T.*; Tomitaka, Sora*; Morooka, Satoshi; Watanabe, Makoto*
Materials Research Letters (Internet), 11(9), p.742 - 748, 2023/09
Wakui, Takashi; Takagishi, Yoichi*; Futakawa, Masatoshi; Tanabe, Makoto*
Jikken Rikigaku, 23(2), p.168 - 174, 2023/06
Cavitation damage on the inner surface of the mercury target for the spallation neutron source occurs by proton bombarding in mercury. The prediction method of the cavitation damage using Monte Carlo simulations was suggested taking variability of the bubble core position and impact pressure distribution into account. The impact pressure distribution was estimated using the inverse analysis with Bayesian optimization was conducted with comparison between cavitation damage distribution obtained from experiment and the cumulative plastic strain distribution obtained from simulation. The average value and spread of maximum impact pressure estimated assuming the Gaussian distribution were 3.1 GPa and 1.2 
m, respectively. Simulation results reproduced experimental results and it can be said that this evaluation method is useful.
Katata, Genki*; Yamaguchi, Takashi*; Watanabe, Makoto*; Fukushima, Keitaro*; Nakayama, Masataka*; Nagano, Hirohiko*; Koarashi, Jun; Tateno, Ryunosuke*; Kubota, Tomohiro
Atmospheric Environment, 298, p.119640_1 - 119640_12, 2023/04
Times Cited Count：1 Percentile：58.15(Environmental Sciences)Ikami, Takaya*; Watanabe, Yuki*; Ogawa, Hiroki*; Takenaka, Mikihito*; Yamada, Norifumi*; Ouchi, Makoto*; Aoki, Hiroyuki; Terashima, Takaya*
ACS Macro Lett (Internet), 10(12), p.1524 - 1528, 2021/12
Times Cited Count：7 Percentile：48.3(Polymer Science)Nagano, Hirohiko; Nakayama, Masataka*; Katata, Genki*; Fukushima, Keitaro*; Yamaguchi, Takashi*; Watanabe, Makoto*; Kondo, Toshiaki*; Atarashi-Andoh, Mariko; Kubota, Tomohiro*; Tateno, Ryunosuke*; et al.
Soil Science and Plant Nutrition, 67(5), p.606 - 616, 2021/10
Times Cited Count：2 Percentile：19.73(Plant Sciences)We analyzed the relationships between nitrogen deposition (deposition of nitrate and ammonium ions) and soil microbial properties in a cool temperate forest surrounded by normally fertilized pasture grasslands in northern Japan. The aim of the present study was to gain the primary information on soil microbial response to moderately elevated nitrogen deposition (
10 kg N ha
y). We established three experimental plots in the forest edge adjacent to grasslands and other three plots in the forest interior at least 700 m away from the grasslands. During May to November 2018, nitrogen deposition in each plot was measured. In August 2018, litter and soil (0-5 cm depth) samples were collected from all plots to measure net nitrogen mineralization and nitrification rates as indicators of microbial activity, and microbial biomass carbon and nitrogen and various gene abundances (i.e. bacterial 16S rRNA, fungal ITS, bacterial amoA, and archaeal amoA genes) as indicators of microbial abundance and structure. Nitrogen deposition in the forest edge was 1.4-fold greater than that in the forest interior, even while the maximum deposition was 3.7 kg N ha. Nitrogen deposition was significantly correlated to the net nitrogen mineralization and nitrification rates and the 16S rRNA and bacterial amoA gene abundances. Microbial community structures were different between litter and soil samples but were similar between the forest edge and interior. Significant correlations of nitrogen deposition to the soil carbon to nitrogen ratio, and the nitrate and ammonium contents were also observed. Thus, our results show that moderately elevated nitrogen deposition in nitrogen-limited forest edges can stimulate microbial activities and abundances in soils.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Sakai, Kenji; Oi, Motoki; Teshigawara, Makoto; Naoe, Takashi; Haga, Katsuhiro; Watanabe, Akihiko*
Journal of Neutron Research, 22(2-3), p.337 - 343, 2020/10
For operating a spallation neutron source and a muon target safely and efficiently, a general control system (GCS) operates within Materials and Life Science Experimental Facility (MLF). GCS administers operation and interlock processes of many instruments under various operation status. Since the first beam injection in 2008, it has operated stably without any serious troubles for more than ten years. GCS has a data storage server storing operational data on status around target stations. It has functioned well to detect and investigate unusual situations by checking data in this server. For continuing stable operation of MLF in future, however, introduction of abnormality sign determination system (ASDS) will be necessary for picking up potential abnormalities of target stations caused by radiation damages, time-related deterioration and so on. It will judge abnormalities from slight state transitions of target stations based on analysis with various operational data throughout proton beams, target stations, and secondary beams during long-term operations. This report mentions present status of GCS, conceptual design of ASDS, and installation of an integral data storage server which can deal with various data for ASDS integrally.
Watanabe, So; Sano, Yuichi; Okada, Makoto*; Matsuura, Haruaki*; Hagura, Naoto*; Kada, Wataru*
Nuclear Instruments and Methods in Physics Research B, 477, p.60 - 65, 2020/08
Times Cited Count：3 Percentile：36.4(Instruments & Instrumentation)IBIL and EXAFS analyses were applied on strucutral analysis of Eu complex formed in adsorbent developed for extraction chromatography. Those analyses revealed slight structural difference between adsorbent and solvent systems.
Th nuclear clock isomer determined by absolute 
-ray energy differenceYamaguchi, Atsushi*; Muramatsu, Haruka*; Hayashi, Tasuku*; Yuasa, Naoki*; Nakamura, Keisuke; Takimoto, Misaki; Haba, Hiromitsu*; Konashi, Kenji*; Watanabe, Makoto*; Kikunaga, Hidetoshi*; et al.
Physical Review Letters, 123(22), p.222501_1 - 222501_6, 2019/11
Times Cited Count：36 Percentile：89.11(Physics, Multidisciplinary)Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：259 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
Imai, Yosuke*; Tokiwa, Yuhei*; Ueno, Shusaku*; Tanida, Hajime; Watanabe, Iwao*; Matsubara, Hiroki*; Takiue, Takanori*; Aratono, Makoto*
Bulletin of the Chemical Society of Japan, 91(10), p.1487 - 1494, 2018/10
Times Cited Count：2 Percentile：8.21(Chemistry, Multidisciplinary)Competitive binding of binary mixed counterions to the headgroups of adsorbed surfactant films has been investigated at solution surfaces by total reflection X-ray absorption fine structure (XAFS) spectroscopy. The obtained extended XAFS 
spectra for bromide counterions are linear combinations of the spectra of fully hydrated bromide ions (free Br) and partially dehydrated bromide ions bound to the headgroups of the surfactant ions (bound Br). From the fraction of bound Br in counterion mixed systems, two series of the relative strengths of counterion binding are proposed for the trimethylammonium (TA
) and 3-methylimidazolium (MIM) headgroups: (a) TA-SO
TA-Cl TA-Br TA-BF and (b) MIM-Br TA-Br TA-BF MIM-BF. For the TA headgroup, matching the hydration of the headgroups and counterions gives series (a) according to Collins' law, which states that the tendency of contact ion pair formation becomes larger when the absolute values of the hydration enthalpies of the ions match. For the MIM headgroup, the number of binding sites of hydrogen bonds between the MIM headgroup and counterion is essential, which leads to series (b) because of competition between the counterion and water for interaction with the MIM headgroup.
Li(
,n)
B reaction in a lower-energy region below the Coulomb barrierDas, S. K.*; Fukuda, Tomokazu*; Mizoi, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Jeong, S. C.*; Ikezoe, Hiroshi*; Matsuda, Makoto; et al.
Physical Review C, 95(5), p.055805_1 - 055805_4, 2017/05
Times Cited Count：3 Percentile：27.61(Physics, Nuclear)Hidaka, Akihide; Nakano, Yoshihiro; Watanabe, Yoko; Arai, Nobuyoshi; Sawada, Makoto; Kanaizuka, Seiichi*; Katogi, Aki; Shimada, Mayuka*; Ishikawa, Tomomi*; Ebine, Masako*; et al.
JAEA-Review 2016-011, 208 Pages, 2016/07
JAEA-Review-2016-011-01.pdf:33.85MBJAEA-Review-2016-011-02.pdf:27.68MB
JAEA has been conducting the Instructor Training Program (ITP) since 1996 under the auspices of MEXT to contribute to human resource development in currently 11 Asian countries in the field of radiation utilization for seeking peaceful use of nuclear energy. ITP consists of Instructor Training Course (ITC), Follow-up Training Course (FTC) and Nuclear Technology Seminars. In the ITP, trainings or seminars relating to technology for nuclear utilization are held in Japan by inviting nuclear related people from Asian countries to Japan and after that, the past trainees are supported during FTC by dispatching Japanese specialists to Asian countries. News Letter is also prepared to provide the broad range of information obtained through the trainings for local people near NPPs in Japan. The present report describes the activities of FY2014 ITP and future challenges for improving ITP more effectively.
LiIshiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Jung, H. S.*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.
Nuclear Instruments and Methods in Physics Research B, 376, p.379 - 381, 2016/06
Times Cited Count：8 Percentile：60.26(Instruments & Instrumentation)Watanabe, Kazuhito; Nakamura, Makoto; Tobita, Kenji; Someya, Yoji; Tanigawa, Hisashi; Uto, Hiroyasu; Sakamoto, Yoshiteru; Araki, Takao*; Asano, Shiro*; Asano, Kazuhito*
Proceedings of 26th IEEE Symposium on Fusion Engineering (SOFE 2015), 6 Pages, 2016/06
Safety studies of a water-cooled fusion DEMO reactor have been performed. In the event of the blanket cooling pipe break outside the vacuum vessel, i.e. ex-vacuum vessel loss of coolant accident (ex-VV LOCA), the pressurized steam and air may lead to damage reactor building walls which have confinement function, and to release the radioactive materials to the environment. In response to this accident, we proposed three cases of confinement strategies. In each case, the pressure and thermal loads to the confinement boundaries and total mass of tritium released to outside the boundaries were analyzed by accident analysis code MELCOR modified for fusion reactor. These analyses developed design parameters to maintain the integrity of the confinement boundaries.
Watanabe, Yoko; Arai, Nobuyoshi; Sawada, Makoto; Kanaizuka, Seiichi; Shimada, Mayuka*; Ishikawa, Tomomi*; Nakamura, Kazuyuki
JAEA-Review 2015-026, 38 Pages, 2015/11
JAEA-Review-2015-026.pdf:10.55MB
JAEA has conducted Nuclear Technology Seminar for Asian countries which plan to introduce NPP, in order to increase the number of engineers and specialists. The Nuclear Technology Seminar on the Basic Radiation Knowledge for School Education Course was launched in 2012 due to increased recognition of the dissemination of the basic knowledge of radiation in public and education sectors as an important issue in the aftermath of the Fukushima Dai-ichi NPP Accident. In response to the requests of past participants, a new exercise "Joint experiment with high school students" was introduced from 2014 to provide an international learning experience for the course participants and the local Japanese students. A new learning material was also developed to help participants to study the basics of radiation in English. All the course activities including the details of preparatory process and course evaluation were described in this report.
Hidaka, Akihide; Nakamura, Kazuyuki; Watanabe, Yoko; Yabuuchi, Yukiko; Arai, Nobuyoshi; Sawada, Makoto; Yamashita, Kiyonobu; Sawai, Tomotsugu; Murakami, Hiroyuki
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 9 Pages, 2015/05
Hoshika, Yasutomo*; Katata, Genki; Deushi, Makoto*; Watanabe, Makoto*; Koike, Takayoshi*; Paoletti, E.*
Scientific Reports (Internet), 5, p.9871_1 - 9871_8, 2015/05
Times Cited Count：88 Percentile：92.53(Multidisciplinary Sciences)The phytotoxic nature of tropospheric ozone can impair forest productivity and affects stomatal functions. Although a delay in stomatal responses (ozone-induced stomatal sluggishness) to fluctuating stimuli has a potential to change carbon and water balance in forests, this effect is not included in the current models for ozone risk assessment to forest. Here we examined effects of ozone-induced stomatal sluggishness on carbon gain and transpiration of global deciduous forests by combining land surface model and global atmospheric chemistry model. Ozone-induced stomatal sluggishness enhances stomatal ozone uptake resulting in facilitating a decline of forest carbon acquisition and also enhancing transpiration. Our findings are consistent with previous experimental and field observational results, indicating that forest trees suffer significant impairment of carbon and water balance through ozone-induced stomatal sluggishness.
