Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
target for measurement of 
I in environmental samples by accelerator mass spectrometryHonda, Maki; Takaku, Yuichi*; Sakaguchi, Aya*; Matsuzaki, Hiroyuki*; Sueki, Keisuke*
Journal of Radioanalytical and Nuclear Chemistry, 334(8), p.5809 - 5820, 2025/08
Times Cited Count：0 Percentile：0.00(Chemistry, Analytical)A series of in-house PdI standards appropriate for AMS was prepared by quantitatively mixing the I/
I isotope standard solution and I solution. The dominant interferences from 
Pd 
were successfully suppressed by adjusting the electrostatic cylindrical analyser, etc., to select the ion beams finely. As a result, the I/I atom ratios of PdI prepared from the seawater and dolomite samples agreed with those prepared as AgI, respectively. The pretreatment time for the new method was shortened by 33% compared to the conventional method. This study demonstrated a new approach to I analysis in AMS that departs from conventional methods.
Kaneta, Yui; Kobayashi, Toru; Tsuji, Takuya; Honda, Mitsunori; Yokoyama, Keiichi; Mampuku, Yuzo*; Yaita, Tsuyoshi*
Clays and Clay Minerals, 73, p.e26_1 - e26_8, 2025/04
Times Cited Count：1 Percentile：40.06(Chemistry, Physical)The desorption behavior of stable Cs adsorbed onto weathered biotite (WB), a clay mineral abundant in Fukushima soils, was investigated using a mechanochemical (MC) method that combines physical grinding by ball impact with a wet process promoting chemical reactions. The results, oxalic acid desorbed Cs to some extent without significantly affecting the layered structure of the clay minerals; ammonium chloride, showed an exfoliation of the layer structure, resulting in a stable desorption of Cs independent of samples. Regarding the real soil samples collected in Fukushima, the MC method using ammonium chloride solution desorbed 80% of 
Cs. In contrast, oxalic acid did not always result in radioactive Cs made sufficiently desorbed for all the samples. Based on these findings, the MC method with ammonium chloride effectively promotes radioactive Cs desorption from interlayers due to synergistic effects from the layered structure's exfoliation and chemical interaction.
shetta lakes in the Soya Coast region and their paleoenvironmental significance with glacial isostatic adjustment in East AntarcticaInoue, Genki*; Honda, Eisuke*; Ito, Keisuke*; Kang, I.*; Seto, Koji*; Tani, Yukinori*; Watanabe, Takahiro; Kashima, Kaoru*; Otani, Shuji*; Yamanaka, Toshiro*; et al.
Quaternary Science Reviews, 338, p.108822_1 - 108822_18, 2024/08
Times Cited Count：0 Percentile：0.00(Geography, Physical)We studied Holocene paleolimnological changes inferred from biomarkers and microscopic observation of microalgae and cyanobacteria in sediment cores from Rundvshetta lakes (Maruwanminami-ike and Maruwan o-ike) in the Soya Coast of East Antarctica, along with sedimentary facies and radiocarbon dating. Coastal marine environment: Maruwanminami-ike (147-72.5 cm, 5,010-2,590 cal BP) and Maruwan-oike (226-47.2 cm, 5,700-3,190 cal BP) were characterized by low biological production with the predominance of diatoms. Transition period of stratified brackish lake environment: Maruwanminami-ike (72.5-65.6 cm, 2,590-2,500 cal BP) and Maruwan-oike (47.2-28.8 cm, 3,190-2,890 cal BP) were characterized by stratified conditions with marine water overlain by freshwater, and a chemocline developed together with an anoxic layer in the bottom of photic zone.
dynamics in the H conductors LaH
O
Tamatsukuri, Hiromu; Fukui, Keiga*; Iimura, Soshi*; Honda, Takashi*; Tada, Tomofumi*; Murakami, Yoichi*; Yamaura, Junichi*; Kuramoto, Yoshio*; Sagayama, Hajime*; Yamada, Takeshi*; et al.
Physical Review B, 107(18), p.184114_1 - 184114_8, 2023/05
Times Cited Count：2 Percentile：13.97(Materials Science, Multidisciplinary)Matsuda, Shohei; Yokoyama, Keiichi; Yaita, Tsuyoshi; Kobayashi, Toru; Kaneta, Yui; Simonnet, M.; Sekiguchi, Tetsuhiro; Honda, Mitsunori; Shimojo, Kojiro; Doi, Reisuke; et al.
Science Advances (Internet), 8(20), p.eabn1991_1 - eabn1991_11, 2022/05
Times Cited Count：13 Percentile：47.61(Multidisciplinary Sciences)no abstracts in English
Iwata, Keiko; Takamizawa, Hisashi; Ha, Yoosung; Shimodaira, Masaki; Okamoto, Yoshihiro; Honda, Mitsunori; Katsuyama, Jinya; Nishiyama, Yutaka
Nuclear Instruments and Methods in Physics Research B, 511, p.143 - 152, 2022/01
Times Cited Count：2 Percentile：25.06(Instruments & Instrumentation)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：66 Percentile：94.76(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.
Sasa, Kimikazu*; Honda, Maki; Hosoya, Seiji*; Takahashi, Tsutomu*; Takano, Kenta*; Ochiai, Yuta*; Sakaguchi, Aya*; Kurita, Saori*; Satou, Yukihiko; Sueki, Keisuke*
Journal of Nuclear Science and Technology, 58(1), p.72 - 79, 2021/01
Times Cited Count：13 Percentile：71.16(Nuclear Science & Technology)
scattering length from 
photoproduction on the proton near the reaction thresholdIshikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.
Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05
Times Cited Count：8 Percentile：49.51(Physics, Nuclear)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：329 Percentile：99.61(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.
Cl in soil near the Fukushima Dai-ichi Nuclear Power PlantOta, Yuki*; Sueki, Keisuke*; Sasa, Kimikazu*; Takahashi, Tsutomu*; Matsunaka, Tetsuya*; Matsumura, Masumi*; Tosaki, Yuki*; Honda, Maki*; Hosoya, Seiji*; Takano, Kenta*; et al.
JAEA-Conf 2018-002, p.99 - 102, 2019/02
no abstracts in English
Iwata, Keiko; Takamizawa, Hisashi; Ha, Yoosung; Okamoto, Yoshihiro; Shimoyama, Iwao; Honda, Mitsunori; Hanawa, Satoshi; Nishiyama, Yutaka
Photon Factory Activity Report 2017, 2 Pages, 2018/00
no abstracts in English
Ho, H. Q.; Morita, Keisuke*; Honda, Yuki; Fujimoto, Nozomu*; Takada, Shoji
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04
Tani, Keiji*; Honda, Mitsuru; Oikawa, Toshihiro*; Shinohara, Koji; Kusama, Yoshinori; Sugie, Tatsuo
Nuclear Fusion, 55(5), p.053010_1 - 053010_15, 2015/05
Times Cited Count：6 Percentile：24.28(Physics, Fluids & Plasmas)The effects of a radial electric field (EF) on the losses of alpha particles and NBI fast ions in typical ITER operation scenarios for both error fields due to test blanket modules (TBMs) and toroidal field (TF) ripple were evaluated using an iterative method to execute an orbit-following Monte-Carlo code and a one-dimensional transport code. The EF effect on the loss of fast ions strongly depends on the operation scenario as well as on the error field. The electric field is very significant in the loss of fast ions in a 9MA ITER operation scenario with a higher safety factor and in the error field associated with TBMs. The EF effect in the error field of TF-ripple is very small in any operation scenario. The radial electric field changes the toroidal precession of fast ions and consequently alter their condition of resonance with the error field, which may account for the EF effect on the loss of fast ions in ITER with TBMs.
Honda, Kei; Ohira, Hiroaki; Mori, Takero
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 12 Pages, 2014/12
Thermal-hydraulics analyses of the reactor upper plenum had been performed in IAEA/Monju-CRP from 2008 to 2012. However, all of the participants got a temperature distribution which didn't agree the measured data on the thermocouple plug. In this study, we re-evaluated the inlet boundary conditions and performed another analysis. The calculated temperature distribution on the thermocouple plug had good agreement with the measured data. Thermocouples and flow guide tubes are attached over the subassembly outlets. The calculated temperature at the thermocouples agreed with the temperature of the boundary conditions. And the calculated temperature at the thermocouples had good agreement with the measured data. Therefore, the temperature at the thermocouples can be regarded as the temperature of the subassembly outlets. From these results, the inlet conditions are an appropriate ones.
Mori, Takero; Sotsu, Masutake; Honda, Kei; Suzuki, Satoshi*; Ohira, Hiroaki
Journal of Energy and Power Engineering, 7(9), p.1644 - 1655, 2013/09
The prototype fast breeder reactor "MONJU" has an ex-vessel fuel storage system which consists mainly of an ex-vessel fuel storage tank (EVST) and an EVST sodium cooling system. EVST sodium cooling system consists of three independent loops. In this study, an analysis and evaluation of the plant dynamics for the spent fuel and the EVSS structural integrity during an station blackout (SBO) were performed. When the number of cooling loops was not changed and natural circulation occurred in only two loops, the sodium temperature in the EVST increased to approximately 450C. However, the structural integrity of the EVSS was maintained. The analytical results, therefore, help clarify the number of necessary cooling loops for efficient decay heat removal and sodium temperature behavior in an SBO.
Ohira, Hiroaki; Honda, Kei; Sotsu, Masutake
Journal of Energy and Power Engineering, 7(4), p.679 - 688, 2013/04
Mori, Takero; Sotsu, Masutake; Honda, Kei; Suzuki, Satoshi*; Ohira, Hiroaki
Proceedings of 20th International Conference on Nuclear Engineering and the ASME 2012 Power Conference (ICONE-20 & POWER 2012) (DVD-ROM), 11 Pages, 2012/07
The prototype fast breeder reactor "Monju" has an ex-vessel fuel storage system which consists mainly of an ex-vessel fuel storage tank (EVST) and an EVST sodium cooling system. EVST sodium cooling system consists of three independent loops. In this study, an analysis and evaluation of the plant dynamics for the spent fuel and the EVSS structural integrity during an station blackout (SBO) were performed. When the number of cooling loops was not changed and natural circulation occurred in only two loops, the sodium temperature in the EVST increased to approximately 450C. However, the structural integrity of the EVSS was maintained. The analytical results, therefore, help clarify the number of necessary cooling loops for efficient decay heat removal and sodium temperature behavior in an SBO.
Ohira, Hiroaki; Honda, Kei; Sotsu, Masutake
Proceedings of 14th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-14) (CD-ROM), 12 Pages, 2011/09
In order to evaluate the upper plenum thermal-hydraulics of the Monju reactor vessel, we have performed detail calculations under the 40% rated power operational condition using high resolution mesh models by a commercial FVM code, FrontFlow/Red. In this study, we applied a high resolution meshes around the flow holes (FHs) on the inner barrel. We mainly made clear that the thermal-hydraulics did not change largely since the flow rates through the FHs were small enough to the total coolant flow rate but were affected largely incase without FHs on the honeycomb structure.
Honda, Kei; Ohira, Hiroaki; Sotsu, Masutake; Yoshikawa, Shinji
Proceedings of 8th International Topical Meeting on Nuclear Thermal-Hydraulics, Operation and Safety (NUTHOS-8) (CD-ROM), 12 Pages, 2010/10
In this study, we calculated the thermal hydraulics of the upper plenum of MONJU by the detailed analysis model using commercial FVM code, FrontFlow/Red. The present analysis model simulates all structures with high resolution meshes. The 1st order upwind and 2nd order central difference scheme were applied to the advection and diffusion terms, respectively. And RNG 
-
model was applied to turbulence modeling. These calculation results indicated that the structures installed in the plenum except for UIS did not affect largely to the temperature and velocity, the flow characteristics in the present results had similar tendencies with porous media approached applied to the UCS region and that the difference between the temperature measured in the UCS region and that of SA outlets is relatively small.
