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Seki, Akiyuki; Yoshikawa, Masanori; Nishinomiya, Ryota*; Okita, Shoichiro; Takaya, Shigeru; Yan, X.
Nuclear Technology, 12 Pages, 2024/00
Times Cited Count：0 Percentile：0.18(Nuclear Science & Technology)Two types of deep neural network (DNN) systems have been constructed with the intent to assist safety operation of a nuclear power plant. One is a surrogate system (SS) that can estimate physical quantities of a nuclear power plant in a computational time of several orders less than a physical simulation model. The other is an abnormal situation identification system (ASIS) that can estimate the state of the disturbance causing an anomaly from physical quantities of a nuclear power plant. Both systems are trained and tested using data obtained from the analytical code for incore and plant dynamics (ACCORD), which reproduces the steady and dynamic behavior of the actual high Temperature engineering test reactor (HTTR) under various scenarios. The DNN models are built by adjusting, the main hyperparameters. Through these procedures, these systems are shown able to perform with a high degree of accuracy.
Dong, F.*; Chen, S.*; Demachi, Kazuyuki*; Yoshikawa, Masanori; Seki, Akiyuki; Takaya, Shigeru
Nuclear Engineering and Design, 404, p.112161_1 - 112161_15, 2023/04
Times Cited Count：3 Percentile：90.12(Nuclear Science & Technology)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.
Yoshikawa, Takehiro*; Sugawara, Shuichi*; Takayanagi, Toshiyuki*; Shiga, Motoyuki; Tachikawa, Masanori*
Chemical Physics, 394(1), p.46 - 51, 2012/02
Times Cited Count：18 Percentile：55.59(Chemistry, Physical)Path-integral molecular dynamics simulations have been performed for porphycene and its isotopic variants in order to understand the effect of isotopic substitution of inner protons on the double proton transfer mechanism. Our quantum simulations show that double proton transfer of the unsubstituted porphycene at the room temperature mainly occurs via a so-called concerted mechanism through the second-order saddle point. In addition, we found that both isotopic substitution and temperature significantly affect the double proton transfer mechanism. For example, the contribution of the stepwise mechanism increases with a temperature increase. It has been found that out-of-plane vibrational motions significantly decrease the contribution of the concerted proton transfer mechanism.
Sugawara, Shuichi*; Yoshikawa, Takehiro*; Takayanagi, Toshiyuki*; Shiga, Motoyuki; Tachikawa, Masanori*
Journal of Physical Chemistry A, 115(42), p.11486 - 11494, 2011/09
Times Cited Count：19 Percentile：56.05(Chemistry, Physical)We have carried out path integral molecular dynamics simulations for hydrated sulfuric acid clusters to understand acid-dissociation and hydrogen-bonded structural rearrangement processes in these clusters from a quantum mechanical viewpoint. We have found that the acid dissociation processes, first and second deprotonation, effectively occur in a hydrated cluster with a specific cluster size. The mechanisms of the proton-transfer processes were analyzed in detail and it was found that the distance between O in sulfuric acid and O in the proton-accepting water is playing an important role. We also found that the water coordination number of the proton-accepting water is important in the proton-transfer processes.
Yoshikawa, Takehiro*; Sugawara, Shuichi*; Takayanagi, Toshiyuki*; Shiga, Motoyuki; Tachikawa, Masanori*
Chemical Physics Letters, 496(1-3), p.14 - 19, 2010/08
Times Cited Count：27 Percentile：67.43(Chemistry, Physical)Full-dimensional path-integral molecular dynamics simulations were performed to determine whether the double proton transfer tautomerization of porphycene is a concerted or a stepwise process. It was found that double proton transfer occurs dominantly through the concerted pathway via the second-order saddle point structure and that contribution of the stepwise mechanism increases with a temperature increase. Nuclear quantum effects play essential roles in determining the proton transfer mechanism.
Sato, Susumu; Miura, Akihiko; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Sako, Hiroyuki; Morishita, Takatoshi; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Kobayashi, Tetsuya
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.298 - 300, 2010/03
no abstracts in English
Miura, Akihiko; Sato, Susumu; Sako, Hiroyuki; Yoshikawa, Hiroshi; Hasegawa, Kazuo; Igarashi, Zenei*; Ikegami, Masanori*
Proceedings of 6th Annual Meeting of Particle Accelerator Society of Japan (CD-ROM), p.733 - 735, 2010/03
no abstracts in English
SO
(HO)
(
=1-6) on semiempirical PM6 potential surfacesKakizaki, Akira*; Motegi, Haruki*; Yoshikawa, Takehiro*; Takayanagi, Toshiyuki*; Shiga, Motoyuki; Tachikawa, Masanori*
Journal of Molecular Structure; THEOCHEM, 901(1-3), p.1 - 8, 2009/05
Quantum path-integral molecular dynamics simulations for a series of sulfuric acid clusters, HSO(HO)(=1-6), were performed using semiempirical PM6 method. It was found that the acid dissociation probability increases with an increase in the cluster size, and that so-called contact-ion-pair structures are dominant in the proton-dissociated clusters. The importance of nuclear quantum effects in the cluster structures and proton-transfer processes is demonstrated.
Sato, Susumu; Miura, Akihiko; Tomisawa, Tetsuo; Sako, Hiroyuki; Morishita, Takatoshi; Ueno, Akira; Hasegawa, Kazuo; Yoshikawa, Hiroshi; Igarashi, Zenei*; Ikegami, Masanori*
Proceedings of 2009 Particle Accelerator Conference (PAC '09) (DVD-ROM), p.3591 - 3593, 2009/05
O)
(=2-7) clusters on semiempirical PM6 potential energy surfacesTakayanagi, Toshiyuki*; Yoshikawa, Takehiro*; Kakizaki, Akira*; Shiga, Motoyuki; Tachikawa, Masanori*
Journal of Molecular Structure; THEOCHEM, 869(1-3), p.29 - 36, 2008/11
Molecular dynamics simulations based on semiempirical PM6 method was carried out to study statistical structures of glycine-water clusters. We found that zwitterionic form is more stable than neutral form as the cluster size increases. The difference in water solvation structures around the neutral or zwitterionic glycine form is also discussed.
Bian, Z.*; Ishii, Hirotake*; Shimoda, Hiroshi*; Yoshikawa, Hidekazu*; Morishita, Yoshitsugu; Kanehira, Yoshiki; Izumi, Masanori
IEICE Transactions on Information and Systems, E90-D(6), p.963 - 974, 2007/06
Times Cited Count：4 Percentile：33.28(Computer Science, Information Systems)This study designed linecode marker, a new type of paper-based marker and proposed recognition, tracking algorithm for it in order to resolve these problems. In comparison of the conventional paper-based markers, such as square markers, circle markers, the linecode marker is not only just easier to set up in complex industrial environment, but also makes it possible to use AR in industrial plant. In order to evaluate the tracking accuracy, trackable distance of the proposed tracking method, an evaluation experiment was conducted in a large room. The experiment results show that: comparing with traditional marker-based tracking method, tracking possible distance extends extremely; tracking accuracy improved to a level of 20cm in 10m distance.
Ikegami, Masanori*; Lee, S.*; Akikawa, Hisashi*; Igarashi, Zenei*; Kondo, Yasuhiro; Okawa, Tomohiro; Ueno, Akira; Sako, Hiroyuki; Ao, Hiroyuki; Sato, Susumu; et al.
KEK Proceedings 2006-15 (CD-ROM), p.347 - 349, 2007/03
We plan to start the beam commissioning of J-PARC linac with reduced energy of 181 MeV in the end of this year. Detailed commissioning strategies for the linac and the succeeding beam transport line, to which we refer as L3BT or Linac-to-3-GeV-synchrotron Beam Transport, will be presented in this talk. The emphasis will be put on the commissioning procedures for two debuncher cavities and a transverse collimator system located in L3BT, because they are key elements in determining the final beam quality at the injection point to the succeeding 3-GeV synchrotron. The unique design and features of the collimator system are also presented.
Sato, Susumu; Tomisawa, Tetsuo; Hiroki, Fumio; Lee, S.*; Igarashi, Zenei*; Ikegami, Masanori*; Ueno, Akira; Kondo, Yasuhiro; Hasegawa, Kazuo; Toyama, Takeshi*; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.467 - 469, 2004/08
As a joint project of KEK and JAERI, a MW class of high intensity proton accelerator (J-PARC), consisting of Linac, 3 GeV-RCS, 50 GeV-MR, is under construction. For this accelerator, it is required to minimize the beam loss (typically, lower than0.1
1 W/m at the linac). To achieve the requirement, beam trajectory needs to be controlled with accuracy of some 100 
m. The first stage of the acceleration (up to 181 MeV during the first stage of construction) is done by linac. The beam position monitor (BPM) in the linac utilizes 4 stripline pickups (50 ohm) on the beam transportation chamber. In this paper, systematic calibration of the BPM is described.
Sato, Susumu; Igarashi, Zenei*; Lee, S.*; Tomisawa, Tetsuo; Hiroki, Fumio; Kishiro, Junichi; Ikegami, Masanori*; Kondo, Yasuhiro; Hasegawa, Kazuo; Ueno, Akira; et al.
Proceedings of 22nd International Linear Accelerator Conference (LINAC 2004), p.429 - 431, 2004/00
As a joint project of KEK and JAERI, a MW class of high intensity proton accelerator (J-PARC), consisting of Linac, 3 GeV-RCS, 50 GeV-MR, is under construction at Tokai, Japan. For this accelerator, it is required to minimize the beam loss (typically, lower than 0.11 W/m at the linac). To achieve the requirement, beam trajectory needs to be controlled with accuracy of some 100 micro-meter. The first stage of the acceleration (up to 181 MeV during the first stage of construction) is done by linac. The beam position monitor (BPM) in the linac utilizes 4 strip-line pickups (50 ohm) on the beam transportation chamber. In this paper, systematic calibration of the BPM is described.
Kurosawa, Masanori*; Ueno, Kenichi; Yoshikawa, Hideki; Yui, Mikazu
JNC TY8400 2003-005, 67 Pages, 2003/05
JNC-TY8400-2003-005.pdf:2.74MB
no abstracts in English
Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.
Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 6 Pages, 2003/04
no abstracts in English
Ouchi, Nobuo; Akaoka, Nobuo*; Asano, Hiroyuki*; Chishiro, Etsuji; Hasegawa, Kazuo; Takeda, Osamu*; Yoshikawa, Hiroshi; Matsuoka, Masanori*; Otani, Toshihiro*; Kako, Eiji*; et al.
Proceedings of 21st International Linear Accelerator Conference, p.488 - 490, 2003/00
Development of a superconducting proton linac is in progress in collaboration with KEK. In order to demonstrate cavity performance and to study stable accelerating field in a pulsed operation, a 600MHz superconducting cryomodule has been fabricated. The cryomodule includes two 5-cell superconducting cavities of 
=0.6 and is designed to perform 2K operation. Cold tests of the cryomodule have been performed at the temperature of 4K and 2K. In the tests, heat leak to the cavities, loaded quality factors, tuning sensitivities, frequency shifts against helium vessel pressure and Lorentz force detuning of the cavities were measured. Most of the measured data agreed with their design values, except for the heat leak and the Lorentz force detuning. As the preliminary horizontal test of the cryomodule, high power RF test has been also performed, where the surface peak fields of 10 and 16 MV/m were achieved in CW and pulsed operation, respectively. Now, the optimization of the RF control system is in progress to demonstrate stable accelerating field in a pulsed operation.
Ishii, Hirotake*; Bian, Z.*; Sekiyama, Tomoki*; Shimoda, Hiroshi*; Yoshikawa, Hidekazu*; Izumi, Masanori; Kanehira, Yoshiki; Morishita, Yoshitsugu
no journal, ,
This study is to development of line-marker and hybrid tracking technology including Multi camera and gyro sensor. Evaluation experiment for new tracking technology is conducted in Nuclear power plant.
Demachi, Kazuyuki*; Chen, S.*; Dong, F.*; Yoshikawa, Masanori; Seki, Akiyuki; Takaya, Shigeru
no journal, ,
no abstracts in English
