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Watanabe, Seiya*; Kawahara, Jun*; Aoki, Takayuki*; Sugihara, Kenta; Takase, Shinsuke*; Moriguchi, Shuji*; Hashimoto, Hirotada*
Engineering Applications of Computational Fluid Mechanics, 17(1), p.2211143_1 - 2211143_23, 2023/00
Times Cited Count:1 Percentile:56.82(Engineering, Multidisciplinary)In tsunami inundations or slope disasters of heavy rain, a lot of floating debris or driftwood logs are included in the flows. The damage to structures from solid body impacts is more severe than the damage from the water pressure. In order to study free-surface flows that include floating debris, developing a high-accurate simulation code of free-surface flows with high performance for large-scale computations is desired. We propose the single-phase free-surface flow model based on the cumulant lattice Boltzmann method coupled with a particle-based rigid body simulation. The discrete element method calculates the contact interaction between solids. An octree-based AMR (Adaptive Mesh Refinement) method is introduced to improve computational accuracy and time-to-solution. High-resolution grids are assigned near the free surfaces and solid boundaries. We conducted two kinds of tsunami flow experiments in the 15 and 70 m water tanks at Hachinohe Institute of Technology and Kobe University to validate the accuracy of the proposed model. The simulation results have shown good agreement with the experiments for the drifting speed, the number of trapped wood pieces, and the stacked angles.
Ohshima, Hiroyuki; Morishita, Masaki*; Aizawa, Kosuke; Ando, Masanori; Ashida, Takashi; Chikazawa, Yoshitaka; Doda, Norihiro; Enuma, Yasuhiro; Ezure, Toshiki; Fukano, Yoshitaka; et al.
Sodium-cooled Fast Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.3, 631 Pages, 2022/07
This book is a collection of the past experience of design, construction, and operation of two reactors, the latest knowledge and technology for SFR designs, and the future prospects of SFR development in Japan. It is intended to provide the perspective and the relevant knowledge to enable readers to become more familiar with SFR technology.
Masuda, Toshiyuki*; Arase, Junko*; Inagaki, Yusuke*; Kawahara, Masatoshi*; Yamaguchi, Kentaro*; Ohara, Takashi; Nakao, Akiko*; Momma, Hiroyuki*; Kwon, E.*; Setaka, Wataru*
Crystal Growth & Design, 16(8), p.4392 - 4401, 2016/08
Times Cited Count:27 Percentile:87.44(Chemistry, Multidisciplinary)Takamatsu, Misao; Kawahara, Hirotaka; Ito, Hiromichi; Ushiki, Hiroshi; Suzuki, Nobuhiro; Sasaki, Jun; Ota, Katsu; Okuda, Eiji; Kobayashi, Tetsuhiko; Nagai, Akinori; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 15(1), p.32 - 42, 2016/03
In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of "MARICO-2" (material testing rig with temperature control) had been broken and bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). This paper describes the results of the in-vessel repair techniques for UCS replacement, which are developed in Joyo. UCS replacement was successfully completed in 2014. In-vessel repair techniques for sodium cooled fast reactors (SFRs) are important in confirming its safety and integrity. In order to secure the reliability of these techniques, it was necessary to demonstrate the performance under the actual reactor environment with high temperature, high radiation dose and remained sodium. The experience and knowledge gained in UCS replacement provides valuable insights into further improvements for In-vessel repair techniques in SFRs.
Ito, Hiromichi; Suzuki, Nobuhiro; Kobayashi, Tetsuhiko; Kawahara, Hirotaka; Nagai, Akinori; Sakao, Ryuta*; Murata, Chotaro*; Tanaka, Junya*; Matsusaka, Yasunori*; Tatsuno, Takahiro*
Proceedings of 2015 International Congress on Advances in Nuclear Power Plants (ICAPP 2015) (CD-ROM), p.1058 - 1067, 2015/05
In the experimental fast reactor Joyo (Sodium-cooled Fast Reactor (SFR)), it was confirmed that the top of the irradiation test sub-assembly had bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). There is a risk of deformation of the UCS and guide sleeve (GS) caused by interference between them unless inclination is controlled precisely. To mitigate the risk, special jack-up equipment for applying three-point suspension was developed. The existing damaged UCS (ed-UCS) jack-up test using the jack-up equipment was conducted on May 7, 2014. As a result of this test, it was confirmed that the ed-UCS could be successfully jacked-up to 1000 mm without consequent overload. The experience and knowledge gained in the ed-UCS jack-up test provides valuable insights and prospects not only for UCS replacement but also for further improving and verifying repair techniques in SFRs.
Son, N. T.*; Trinh, X. T.*; Lvile, L. S.*; Svensson, B. G.*; Kawahara, Kotaro*; Suda, Jun*; Kimoto, Tsunenobu*; Umeda, Takahide*; Isoya, Junichi*; Makino, Takahiro; et al.
Physical Review Letters, 109(18), p.187603_1 - 187603_5, 2012/11
Times Cited Count:201 Percentile:97.98(Physics, Multidisciplinary)Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.
Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01
Times Cited Count:52 Percentile:71.15(Biochemistry & Molecular Biology)Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.
Ashida, Takashi; Takamatsu, Misao; Kawahara, Hirotaka; Maeda, Shigetaka; Maeda, Yukimoto; Hara, Masahide*; Kato, Jungo*
no journal, ,
no abstracts in English
Suzuki, Nobuhiro; Ito, Hiromichi; Sasaki, Jun; Okawa, Toshikatsu; Kawahara, Hirotaka; Kobayashi, Tetsuhiko; Sakao, Ryuta*; Murata, Chotaro*; Tanaka, Junya*; Matsusaka, Yasunori*; et al.
no journal, ,
no abstracts in English
Ota, Katsu; Ito, Hiromichi; Ushiki, Hiroshi; Yoshihara, Shizuya; Tobita, Shigeharu; Kawahara, Hirotaka; Hara, Masahide*; Okazaki, Hiroyoshi*; Tanaka, Junya*; Tatsuno, Takahiro*
no journal, ,
no abstracts in English
Ushiki, Hiroshi; Ito, Hiromichi; Okuda, Eiji; Suzuki, Nobuhiro; Sasaki, Jun; Ota, Katsu; Kawahara, Hirotaka; Takamatsu, Misao; Nagai, Akinori; Okawa, Toshikatsu
no journal, ,
In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of MARICO-2 (material testing rig with temperature control) had bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS) in 2007. As a part of the restoration work, UCS replacement was begun at March 24, 2014 and was completed at December 17. In-vessel repair (including observation) for sodium-cooled fast reactors (SFRs) is distinct from that for light water reactors and necessitates independent development. Application of developed in-vessel repair techniques to operation and maintenance of SFRs enhanced their safety and integrity. There is little UCS replacement experience in the world and this experience and insights, which were accumulated in the replacement work of in-vessel large sturucture (UCS) used for more than 30 years, are expected to improve the in-vessel repair techniques in SFRs.