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Cs concentrations in coastal sediments off FukushimaSuzuki, Shotaro*; Amano, Yosuke*; Enomoto, Masahiro*; Matsumoto, Akira*; Morioka, Yoshiaki*; Sakuma, Kazuyuki; Tsuruta, Tadahiko; Kaeriyama, Hideki*; Miura, Hikaru*; Tsumune, Daisuke*; et al.
Science of the Total Environment, 831, p.154670_1 - 154670_15, 2022/07
Tanaka, Nobuyuki; Sawada, Shinichi*; Sugimoto, Chihiro; Yamaki, Tetsuya*
QST-M-33; QST Takasaki Annual Report 2020, P. 37, 2022/03
We have been developing the ion exchange membranes by a radiation grafted polymerization method to improve HI concentration performance for Electro-electrodialysis (EED) in the thermochemical water-splitting hydrogen production iodine-sulfur process. We verify to adopt the cation exchange membrane prepared by ion-track grafted technique. In this membrane preparation technique, one-dimensional cylindrical ion-channel can be formed in the base polymer film by the radiation of the heavy ion beam. And, the excess swelling of the ion-channel could be prevented, expecting that the HI concentration performance could be improved. In our works, The HI concentration experiment was conducted by the electric cell assembled the membrane prepared by the ion-track grafting technique. The HI composition of the tested solution increased, indicating that the tested membrane can operate HI concentration by EED.
Kumagai, Tomohisa*; Miura, Yasufumi*; Miura, Naoki*; Marie, S.*; Almahdi, R.*; Mano, Akihiro; Li, Y.; Katsuyama, Jinya; Wada, Yoshitaka*; Hwang, J.-H.*; et al.
Journal of Pressure Vessel Technology, 144(1), p.011509_1 - 011509_18, 2022/02
To predict fracture behavior for ductile materials, some ductile fracture simulation methods different from classical approaches have been investigated based on appropriate models of ductile fracture. For the future use of the methods to overcome restrictions of classical approaches, the applicability to the actual components is of concern. In this study, two benchmark problems on the fracture tests supposing actual components were provided to investigate prediction ability of simulation methods containing parameter decisions. One was the circumferentially through-wall and surface cracked pipes subjected to monotonic bending, and the other was the circumferentially through-wall cracked pipes subjected to cyclic bending. Participants predicted the ductile crack propagation behavior by their own approaches, including FEM employed GTN yielding function with void ratio criterion, are FEM employed GTN yielding function, FEM with fracture strain or energy criterion modified by stress triaxiality, XFEM with J or delta J criterion, FEM with stress triaxiality and plastic strain based ductile crack propagation using FEM, and elastic-plastic peridynamics. Both the deformation and the crack propagation behaviors for monotonic bending were well reproduced, while few participants reproduced those for cyclic bending. To reproduce pipe deformation and fracture behaviors, most of groups needed parameters which were determined toreproduce pipe deformation and fracture behaviors in benchmark problems themselves and it is still difficult to reproduce them by using parameters only from basic materials tests.
Wada, Yuki; Furuichi, Noriyuki*; Tsuji, Yoshiyuki*
European Journal of Mechanics B, Fluids, 91, p.233 - 243, 2022/01
Wada, Yuki*; Matsumoto, Takahiro*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Furuta, Yoshihiro*; Yonetoku, Daisuke*; Sawano, Tatsuya*; Okada, Go*; Nanto, Hidehito*; et al.
Physical Review Research (Internet), 3(4), p.043117_1 - 043117_31, 2021/12
Sonehara, Masateru; Uchibori, Akihiro; Aoyagi, Mitsuhiro; Kawada, Kenichi; Takata, Takashi; Ohshima, Hiroyuki
Dai-25-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (Internet), 3 Pages, 2021/07
In sodium-cooled fast reactors (SFRs), it has been pointed out that molten fuel may be discharged from the core during a severe accident (SA) accompanied by core damage, and may solidify into debri particles with diameters ranging from several millimeters to several hundred micrometers due to interaction with the sodium coolant and accumulate at the bottom of the reactor vessel. Therefore, it is necessary to understand the behavior of such debri particles appropriately to evaluate the SA event progression. To meet these requirements, a molten fuel behavior analysis code using dissipative particle dynamics (DPD), a kind of particle method, has been developed as a part of the SPECTRA code, tool for consistent analysis of in-vessel and ex-vessel events in sodium fast reactor accidents. In this study, it was found that the new analyses code can reproduce sedimentation behavior of particles by adding a new stress term in the shear direction.
Tsuchiya, Harufumi; Enoto, Teruaki*; Wada, Yuki*; Furuta, Yoshihiro; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Umemoto, Daigo*; Makishima, Kazuo*; GROWTH collaboration*
Proceedings of Science (Internet), 358, 6 Pages, 2021/07
Tanaka, Nobuyuki; Sawada, Shinichi*; Yamaki, Tetsuya*; Kodaira, Takahide*; Kimura, Takehiro*; Nomura, Mikihiro*
Chemical Engineering Science, 237, p.116575_1 - 116575_11, 2021/06
Times Cited Count：0 Percentile：0(Engineering, Chemical)We have been developing the ion exchange membranes by a radiation grafted polymerization method to improve HI concentration performance for Electro-electrodialysis (EED) in the thermochemical water-splitting hydrogen production iodine-sulfur process. In this work, the crosslinking structures were introduced to the ion exchange membranes. The proton conductivity (
), transport number (t
), and water permeation factor (
) of these crosslinked ion exchange membranes were measured and the effect of crosslinks to these performance indexes were investigated. The introduction of crosslinks was found to improve the selectivity of H
and water transport (increase of t and decrease of ), although the somewhat decreased. The EED model that we established to discuss the permeation mechanism of EED system was used to theoretically analyze the effect of crosslink on the performance indexes. Based on this analysis of measurement results, the introduction of the crosslink was found to little affect the absorbed amount of HIx solution and H diffusion coefficient in the tested membranes, whereas it could lead to decrease I
diffusion coefficient. The results of and t could reflect these effects. In addition, we found the fact that crosslink can inhibit the swelling due to the absorption of the HIx solution. As a result, the value decreased owing to the introduction of crosslink.
Wada, Yuki*; Enoto, Teruaki*; Kubo, Mamoru*; Nakazawa, Kazuhiro*; Shinoda, Taro*; Yonetoku, Daisuke*; Sawano, Tatsuya*; Yuasa, Takayuki*; Ushio, Tomoo*; Sato, Yosuke*; et al.
Geophysical Research Letters, 48(7), 11 Pages, 2021/04
Times Cited Count：1 Percentile：0(Geosciences, Multidisciplinary)During three winter seasons from November 2016 to March 2019, 11 gamma-ray glows were detected at a single observation site of our ground-based gamma-ray monitoring network in Kanazawa, Japan. These events are analyzed with observations of an X-band radar network, a ceilometer, a disdrometer, and a weather monitor. All the detected glows were connected to convective high-reflectivity regions of more than 35 dBZ, developed up to an altitude of 
2 km. They were also accompanied by heavy precipitation of graupels. Therefore, graupels in the lower layer of thunderclouds that correspond to high-reflectivity regions can form strong electric fields producing gamma-ray glows. Also, these events are compared with a limited sample of nondetection cases, but no significant differences in meteorological conditions were found between detection and nondetection cases in the present study.
Kajino, Mizuo*; Adachi, Koji*; Igarashi, Yasuhito*; Satou, Yukihiko; Sawada, Morihiro*; Sekiyama, Tsuyoshi*; Zaizen, Yuji*; Saya, Akane*; Tsuruta, Haruo*; Moriguchi, Yuichi*
Journal of Geophysical Research; Atmospheres, 126(1), 23 Pages, 2021/01
Times Cited Count：2 Percentile：87.32(Meteorology & Atmospheric Sciences)Takeda, Takeshi; Wada, Yuki; Shibamoto, Yasuteru
World Journal of Nuclear Science and Technology, 11(1), p.17 - 42, 2021/01
Wada, Yuki*; Enoto, Teruaki*; Nakazawa, Kazuhiro*; Odaka, Hirokazu*; Furuta, Yoshihiro; Tsuchiya, Harufumi
Journal of Geophysical Research; Atmospheres, 125(20), 17 Pages, 2020/10
Times Cited Count：1 Percentile：0.01(Meteorology & Atmospheric Sciences)Yuasa, Takayuki*; Wada, Yuki*; Enoto, Teruaki*; Furuta, Yoshihiro; Tsuchiya, Harufumi; Hisadomi, Shohei*; Tsuji, Yuna*; Okuda, Kazufumi*; Matsumoto, Takahiro*; Nakazawa, Kazuhiro*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2020(10), p.103H01_1 - 103H01_27, 2020/10
Times Cited Count：2 Percentile：32.18(Physics, Multidisciplinary)Itoi, Hiroyuki*; Ninomiya, Takeru*; Hasegawa, Hideyuki*; Maki, Shintaro*; Sakakibara, Akihiro*; Suzuki, Ryutaro*; Kasai, Yuto*; Iwata, Hiroyuki*; Matsumura, Daiju; Owada, Mao*; et al.
Journal of Physical Chemistry C, 124(28), p.15205 - 15215, 2020/07
Times Cited Count：4 Percentile：61.86(Chemistry, Physical)Sawada, Shinichi*; Kimura, Takehiro*; Nishijima, Haruyuki*; Kodaira, Takahide*; Tanaka, Nobuyuki; Kubo, Shinji; Imabayashi, Shinichiro*; Nomura, Mikihiro*; Yamaki, Tetsuya*
International Journal of Hydrogen Energy, 45(27), p.13814 - 13820, 2020/05
Times Cited Count：1 Percentile：15.95(Chemistry, Physical)An electrochemical membrane Bunsen reaction using a cation exchange membrane (CEM) is a key to achieving an iodine-sulfur (IS) thermochemical water splitting process for mass-production of hydrogen. In this study, we prepared both the radiation-grafted CEM with a high ion exchange capacity (IEC) and the highly-porous Au-electroplated anode, and then used them for the membrane Bunsen reaction to reduce the cell overvoltage. The high-IEC grafted CEM exhibited low resistivity for proton transport, while the porous Au anode had a large effective surface area for anodic SO
oxidation reaction. As a result, the cell overvoltage for the membrane Bunsen reaction was significantly reduced to 0.21 V at 200 mA/cm
, which was only one-third of that of the previous test using the commercial CEM and non-porous anode. From the analysis of the current-voltage characteristics, employment of the grafted CEM was found to be more effective for the overvoltage reduction compared to the porous Au anode.
Wada, Yuki*; Nakazawa, Kazuhiro*; Enoto, Teruaki*; Furuta, Yoshihiro; Yuasa, Takayuki*; Makishima, Kazuo*; Tsuchiya, Harufumi
Physical Review D, 101(10), p.102007_1 - 102007_6, 2020/05
Times Cited Count：1 Percentile：22.99(Astronomy & Astrophysics)Kumada, Takayuki; Oba, Yojiro; Motokawa, Ryuhei; Morooka, Satoshi; Tominaga, Aki; Tanida, Hajime; Shobu, Takahisa; Konno, Azusa; Owada, Kenji*; Ono, Naoko*; et al.
Journal of Nuclear Materials, 528, p.151890_1 - 151890_7, 2020/01
Times Cited Count：0 Percentile：0.01(Materials Science, Multidisciplinary)We have developed an anomalous small-angle X-ray scattering (ASAXS) diffractometer in SPring-8 to investigate irradiation-induced nanostructural change in ion-beam irradiated stainless steel. A thermally-aged MA956 stainless steel sample displays power-law scattering that follows the Porod law at the magnitude of scattering vector, Q, below 0.5 nm
and an overlapped shoulder around 0.7 nm. After the ion-beam irradiation, the intensity of the shoulder remained unchanged, whereas that of the power-law scattering nearly doubled. This result indicates that none of the structural parameters of the Cr-rich nanoprecipitates, such as the number density, size, and interface roughness, were changed by the irradiation.
Wada, Yuki; Le, T. D.; Satou, Akira; Shibamoto, Yasuteru; Yonomoto, Taisuke
Journal of Nuclear Science and Technology, 57(1), p.100 - 113, 2020/01
Times Cited Count：2 Percentile：42.44(Nuclear Science & Technology)Satou, Akira; Wada, Yuki; Shibamoto, Yasuteru; Yonomoto, Taisuke
Nuclear Engineering and Design, 354, p.110164_1 - 110164_10, 2019/12
Times Cited Count：6 Percentile：75.46(Nuclear Science & Technology)JAEA has conducted a series of experimental researches on the Post-boiling transition heat transfer, transient critical heat flux and rewetting for BWRs. Experimental data bases covering the anticipated operational conditions was developed; the significance of the precursor cooling was identified. This paper presents approaches of the present research focusing on the anticipated transient without scram, effects of the spacer and physical understanding of the phenomena for development of mechanistic model together with promising results obtained so far.
Sonoda, Tetsu*; Katayama, Ichiro*; Wada, Michiharu*; Iimura, Hideki; Sonnenschein, V.*; Iimura, Shun*; Takamine, Aiko*; Rosenbusch, M.*; Kojima, Takao*; Ahn, D. S.*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2019(11), p.113D02_1 - 113D02_12, 2019/11
Times Cited Count：0 Percentile：0.01(Physics, Multidisciplinary)An in-flight separator, BigRIPS, at RIBF in RIKEN provides each experiment with specific nuclides separated from many nuclides produced by projectile fragmentation or in-flight fission. In this process, nuclides other than separated ones are discarded on the slits in BigRIPS, although they include many nuclides interested from the view point of nuclear structure. In order to extract these nuclides for parasitic experiments, we are developing a method using laser ion-source (PALIS). A test experiment with 
Se beam from RIBF has been performed by using a gas cell set in BigRIPS. Unstable nuclides around 
Se were stopped in the gas cell in accordance with a calculation using LISE code. The stopping efficiency has been estimated to be about 30%. As a next step, we will establish the technique for extracting reaction products from the gas cell.
