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Hirata, Sakiko*; Kusaka, Ryoji; Meiji, Shogo*; Tamekuni, Seita*; Okudera, Kosuke*; Hamada, Shoken*; Sakamoto, Chihiro*; Honda, Takumi*; Matsushita, Kosuke*; Muramatsu, Satoru*; et al.
Inorganic Chemistry, 62(1), p.474 - 486, 2023/01
Times Cited Count：0 Percentile：0.01(Chemistry, Inorganic & Nuclear)Matsushita, Hatsuki*; Kobayashi, Ren*; Sakai, Takaaki*; Kato, Shinya; Matsuba, Kenichi; Kamiyama, Kenji
Proceedings of 13th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-13) (Internet), 9 Pages, 2022/09
During core disruptive accidents in sodium-cooled fast reactors, the molten core material flows through flow channels, such as the control rod guide tubes, into the core inlet plenum under the core region. The molten core material can be cooled and solidified while impinging on a horizontal plate of the inlet plenum in a sodium coolant. However, the solidification and cooling behaviors of molten core materials impinged on a horizontal structure have not been sufficiently studied thus far. Notably, this is an important phenomenon that needs to be elucidated from the perspective of improving the safety of sodium-cooled fast reactors. Accordingly, a series of experiments on discharging a simulated molten core material (alumina: Al
O
) into a sodium coolant on a horizontal structure was conducted at the experimental facility of the National Nuclear Center of the Republic of Kazakhstan. In this study, analyses on the sodium experiments using SIMMER-III as the fast reactor safety evaluation code were performed. The analysis methods were validated by comparing the results and experiment data. In addition, the cooling and solidification behaviors during jet impingement were evaluated. The results indicated that the molten core material exhibited fragmentation owing to the impingement on the horizontal plate and was, therefore, scattered toward the periphery. Furthermore, the simulated molten core material was evaluated to be cooled by sodium and subsequently solidified.
Uchida, Mao*; Alzahrani, H.*; Shiono, Mikihito*; Sakai, Takaaki*; Matsushita, Kentaro; Ezure, Toshiki; Tanaka, Masaaki
Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 16 Pages, 2022/03
Gas entrainment from cover gas is one of key issues for sodium-cooled fast reactors design to prevent unexpected effects to core reactivity. A vortex model based evaluation method has been developed to evaluate the surface vortex gas core growth at the free surface in the reactor vessel. In this study, water experiments were performed to clarify the prediction accuracy for the vortex gas core growth during the vortex drift motion using a circulating water tunnel with an open flow channel test section. Gas core growth were predicted by applying the evaluation method to the numerical analyses performed in the same geometry of the experiments, and compared with the experimental results. It was observed the gas core growth became large at downstream region where downward velocity became large in experiment. However, the gas core length which were predicted from numerical result showed a discrepancy with the experimental result on the peak position and an overestimation of peak value.
Matsushita, Kentaro; Fujisaki, Tatsuya*; Ezure, Toshiki; Tanaka, Masaaki; Uchida, Mao*; Sakai, Takaaki*
Keisan Kogaku Koenkai Rombunshu (CD-ROM), 26, 6 Pages, 2021/05
For the gas entrainment vortex at the free surface in sodium-cooled fast reactors, development of the numerical analysis method to evaluate amount of the gas entrainment from the free surface has been developing. In this paper, the automatic creation of analysis meshes which can suppress the calculation cost while maintaining the prediction accuracy of the vortex shape is investigated, and the adaptive mesh refinement (AMR) method is examined to the creation of analysis mesh applying to the unsteady vortex system. The refined mesh based on the criterion evaluated by vorticity, Q-value as second invariant of the velocity and the discriminant for the eigen equation of the velocity gradient tensor is considered, and it found that the AMR method based on Q-value can refine the analysis meshes most efficiently.
He
excimer cluster tracers in superfluid helium-4 via neutron-
He absorption reactionSonnenschein, V.*; Tsuji, Yoshiyuki*; Kokuryu, Shoma*; Kubo, Wataru*; Suzuki, So*; Tomita, Hideki*; Kiyanagi, Yoshiaki*; Iguchi, Tetsuo*; Matsushita, Taku*; Wada, Nobuo*; et al.
Review of Scientific Instruments, 91(3), p.033318_1 - 033318_12, 2020/03
Times Cited Count：0 Percentile：0(Instruments & Instrumentation)He
clusters via neutron-He absorption reaction toward visualization of full velocity field in quantum turbulenceMatsushita, Taku*; Sonnenschein, V.*; Guo, W.*; Hayashida, Hirotoshi*; Hiroi, Kosuke; Hirota, Katsuya*; Iguchi, Tetsuo*; Ito, Daisuke*; Kitaguchi, Masaaki*; Kiyanagi, Yoshiaki*; et al.
Journal of Low Temperature Physics, 196(1-2), p.275 - 282, 2019/07
Times Cited Count：1 Percentile：4.76(Physics, Applied)
Sc and development of the 
subshell closureSteppenbeck, D.*; Takeuchi, Satoshi*; Aoi, Nori*; Doornenbal, P.*; Matsushita, Masafumi*; Wang, H.*; Baba, Hidetada*; Go, Shintaro*; Holt, J. D.*; Lee, J.*; et al.
Physical Review C, 96(6), p.064310_1 - 064310_10, 2017/12
Times Cited Count：18 Percentile：80.82(Physics, Nuclear)no abstracts in English
-ray spectroscopy of 
Mg via knockout reactions at intermediate energiesMomiyama, Satoru*; Doornenbal, P.*; Scheit, H.*; Takeuchi, Satoshi*; Niikura, Megumi*; Aoi, Nori*; Li, K.*; Matsushita, Masafumi*; Steppenbeck, D.*; Wang, H.*; et al.
Physical Review C, 96(3), p.034328_1 - 034328_8, 2017/09
Times Cited Count：6 Percentile：47.01(Physics, Nuclear)no abstracts in English
Hayashi, Koichi*; Oyama, Kenji*; Happo, Naohisa*; Matsushita, Tomohiro*; Hosokawa, Shinya*; Harada, Masahide; Inamura, Yasuhiro; Nitani, Hiroaki*; Shishido, Toetsu*; Yubuta, Kunio*
Science Advances (Internet), 3(8), p.e1700294_1 - e1700294_7, 2017/08
Ne at 
230 MeV/nucleonLee, J.*; Liu, H.*; Doornenbal, P.*; Kimura, Masaaki*; Minomo, Kosho*; Ogata, Kazuyuki*; Utsuno, Yutaka; Aoi, Nori*; Li, K.*; Matsushita, Masafumi*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2016(8), p.083D01_1 - 083D01_7, 2016/08
Times Cited Count：6 Percentile：44.73(Physics, Multidisciplinary)no abstracts in English
Ar and the 
=32 subshell closureSteppenbeck, D.*; Takeuchi, Satoshi*; Aoi, Nori*; Doornenbal, P.*; Matsushita, Masafumi*; Wang, H.*; Utsuno, Yutaka; Baba, Hidetada*; Go, Shintaro*; Lee, J.*; et al.
Physical Review Letters, 114(25), p.252501_1 - 252501_6, 2015/06
Times Cited Count：44 Percentile：87.83(Physics, Multidisciplinary)The neutron-rich nucleus Ar is produced by the fragmentation reactions of 
Ca, Sc, and 
Ti at the RIBF facility in RIKEN, and its deexcited rays are observed for the first time. The first 
level in Ar is identified to lie at 1178(18)keV from the most intense -ray spectra. This experimental data, together with the systematics of the levels for surrounding nuclei, is analyzed with large-scale shell-model calculations. Consequently, the 
sub-shell gap in Ar is equivalent to that of 
Ca, thus making the level in Ar higher than that of 
Ar. The shell-model calculation also predicts that the sub-shell gap enhances in going from Ca to Ar, which will be verified by forthcoming experiments for Ar.
CaSteppenbeck, D.*; Takeuchi, Satoshi*; Aoi, Nori*; Doornenbal, P.*; Matsushita, Masafumi*; Wang, H.*; Baba, Hidetada*; Fukuda, Naoki*; Go, Shintaro*; Homma, Michio*; et al.
Nature, 502(7470), p.207 - 210, 2013/10
Times Cited Count：285 Percentile：99.78(Multidisciplinary Sciences)no abstracts in English
FeO
F
(x 
0.44)Tsujimoto, Yoshihiro*; Yamaura, Kazunari*; Hayashi, Naoaki*; Kodama, Katsuaki; Igawa, Naoki; Matsushita, Yoshitaka*; Katsuya, Yoshio*; Shirako, Yuichi*; Akaogi, Masaki*; Muromachi, Eiji*
Chemistry of Materials, 23(16), p.3652 - 3658, 2011/08
Times Cited Count：26 Percentile：59.91(Chemistry, Physical)Topotactic reaction of the Ruddlesden-Popper phase SrFeO
(
0.18) with polytetrafluoroethylene yields a highly fluorinated phase SrFeOF (x 0.44), compared with SrFeO
F
prepared by the reaction of SrFeO and F gas. Structure analyses based on powder neutron diffraction, synchrotron powder diffraction, and 
Fe M
ssbauer spectroscopy measurements demonstrate that the new oxyfluoride perovskite has no anion deficiencies and adopts the tetragonal structure (space group 
4/
) with lattice constants 
= 3.87264(6) 
and 
= 21.3465(6) at room temperature. The fluoride ions preferentially occupy the terminal apical anion sites with oxide ions in a disordered manner, which results in square pyramidal coordination around iron.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Matsushita, Yoshitaka*; Izumi, Fujio*; Kobayashi, Kiyoshi*; Igawa, Naoki; Kitazawa, Hideaki*; Oyama, Yukiko*; Miyoshi, Shogo*; Yamaguchi, Shu*
Nuclear Instruments and Methods in Physics Research A, 600(1), p.319 - 321, 2009/02
Times Cited Count：22 Percentile：80.43(Instruments & Instrumentation)The neutron powder diffraction data of the apatite-type La-silicate La
SiO
was measured at 10 K and the Rietveld refinement on the basis of hexagonal P6/m was successfully carried out. The obtained cell parameters were =0.971297(7) nm, and = 0.717950(6) nm. On the Rietveld refinement supported by maximum entropy method, the interstitial oxygen positions show randomly distribution around La2 site, and they may give the driving-force of high ionic conductivity to the main ionic conduction site O4.
atoms at the wall on the production profile of H
ions in large negative ion sourcesTakado, Naoyuki*; Matsushita, Daisuke*; Fujino, Ikuro*; Hatayama, Akiyoshi*; Tobari, Hiroyuki; Inoue, Takashi
Review of Scientific Instruments, 79(2), p.02A503_1 - 02A503_4, 2008/02
Times Cited Count：2 Percentile：14.59(Instruments & Instrumentation)Production and transport process of the H atoms are numerically simulated using a three-dimensional Monte Carlo transport code. The code was applied to the "JAEA 10 ampere negative ion source" under Cs-seeded condition to obtain a spatial distribution of surface-produced H ions. In this analysis, we focus on the effect of the energy relaxation of the H atoms at the wall on the H ion production from the H atoms. The result indicates that, by considering the energy relaxation of the H atoms at the wall, the production profile of the surface-produced H ion is well reflected in the production profile of the H atom production.
ion transport processes in Cs-seeded negative ion sourcesMatsushita, Daisuke*; Takado, Naoyuki*; Hatayama, Akiyoshi*; Inoue, Takashi
Review of Scientific Instruments, 79(2), p.02A527_1 - 02A527_4, 2008/02
Times Cited Count：5 Percentile：28.3(Instruments & Instrumentation)The H ion transport processes are numerically simulated to understand the extraction process of surface-produced H ions. The three-dimensional transport code using Monte Carlo method has been applied to calculate the H ion extraction probabilities in the model geometry of the JAEA 10 ampere negative ion source. The roles of (1) filter magnetic field and (2) collisions with neutrals (H atoms and H molecules) on the H ion extraction are systematically studied. The results show that H ions are extracted mainly by the filter magnetic field under the low gas pressure condition. The simulation results of extracted H ion beam intensity in the JAEA 10 ampere negative ion source without the magnetic filter tend to be smaller than the experimental results, especially under the low pressure condition.
Matsumura, Akira*; Yamamoto, Tetsuya*; Shibata, Yasushi*; Nakai, Kei*; Zhang, T.*; Matsushita, Akira*; Takano, Shingo*; Endo, Kiyoshi*; Akutsu, Hiroyoshi*; Yamamoto, Kazuyoshi; et al.
Research and Development in Neutron Capture Therapy, p.1073 - 1078, 2002/09
Since 1998 to 2002, a new clinical trial of an intraoperative boron neutron capture therapy (IOBNCT) at JRR-4 of Japan Atomic Energy Institute (JAERI) using BSH with mixed thermal/epithermal neutron beam has been accomplished. There have been 9 patients included in this study. The median survival time (MST) in GBM was 19.8 months and 16.8 months in AA. IOBNCT with mixed thermal/epithermal neutron beam provide better primary radiation effect than conventional therapy in selected cases. Our phase I/II clinical trial was effective in local tumor control. Further clinical trial with new design should be performed to prove the efficacy of IOBNCT.
Yamamoto, Tetsuya*; Matsumura, Akira*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Torii, Yoshiya; Endo, Kiyoshi*; Matsushita, Akira*; Shibata, Yasushi*; Nose, Tadao*
Research and Development in Neutron Capture Therapy, p.415 - 418, 2002/09
Dose measurements in a patient's brain undergoing intraoperative BNCT (IOBNCT) were compared with calculations by a JAERI computational dosimetry system (JCDS). The maximum thermal neutron flux on the brain surface from the postirradiation measurement averaged 2.33
0.37(
10
cm
s
) and the vascular boron dose averaged 11.41.2 (9.6-12.7) Gy. Using JCDS, the maximum thermal neutron flux in the irradiated volume averaged 2.210.33(10cms), while the target vascular dose averaged 5.7 Gy and varied from 3.5 to 7.8 Gy. As such, in the dose planning for intra-operative irradiation, practical use of JCDS is recommended for uniform volume-dose control of postsurgical brain in IOBNCT.
Yamamoto, Tetsuya*; Matsumura, Akira*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Hori, Naohiko; Torii, Yoshiya; Endo, Kiyoshi*; Matsushita, Akira*; Yoshida, Fumiyo*; Shibata, Yasushi*; et al.
Research and Development in Neutron Capture Therapy, p.697 - 700, 2002/09
The RBE of dose components generated in boron neutron capture therapy (BNCT) were separately determined in neutron beams at JRR-4. The cell killing effect of the neutron beam with or without the presence of 10B was highly dependent on the neutron beam used, according to the epithermal and fast neutron content in the beam. RBE (BARBEboron) values of the boron capture reaction for an epithermal (ENB), a mixed thermal-epithermal (TNB-1), and a thermal (TNB-2) neutron beams were 3.990.24, 3.040.19 and 1.430.08, respectively.
