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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
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.
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count：13 Percentile：99.06(Quantum Science & Technology)Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11
Times Cited Count：3 Percentile：86.59(Physics, Atomic, Molecular & Chemical)Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12
Times Cited Count：7 Percentile：90.97(Physics, Atomic, Molecular & Chemical)Nagamatsu, Aiko*; Casolino, M.*; Larsson, O.*; Ito, Tsuyoshi*; Yasuda, Nakahiro*; Kitajo, Keiichi*; Shimada, Ken*; Takeda, Kazuo*; Tsuda, Shuichi; Sato, Tatsuhiko
Physics Procedia, 80, p.25 - 35, 2015/12
Times Cited Count：12 Percentile：95.25(Physics, Applied)JAXA has been investigated the effect of the shielding material for dosimeters in the ISS Russian segment under the ALTCRISS project. The PADLES package is a passive dosimeters which usually consists of two types of passive and integrating dosimeters, a CR-39 plastic nuclear track detector and a thermoluminescence dosimeter. In the ALTCRISS experiments, both tissue-equivalent material CR-39 PNTDs and NAN-JAERI were enclosed in the PADLES packages as radiators for CR-39 to precisely measure a personal exposed doses. We compared the doses obtained by PADLESs with or without the PEs, and with or difference of the two tissue-equivalent materials. The results of space radiation measurements of the ALTCRISS project Phase 1 to 4 using the PADLES system will be reported in this time: Phase 1 experiments was from December 2005 to April 2006, Phase 2 was from April to September 2006, phase 3 was from Sep 2006 to April 2007, and Phase 4 was conducted from May to October 2007.
Ito, Kei; Ohno, Shuji; Koizumi, Yasuo*; Kawamura, Takumi*
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 10 Pages, 2014/12
Ito, Kei; Tanaka, Masaaki; Ohno, Shuji; Ohshima, Hiroyuki
JAEA-Research 2014-023, 34 Pages, 2014/11
JAEA-Research-2014-023.pdf:4.48MB
In a sodium-cooled fast reactor, inert gas (bubbles or dissolved gas) exists in the primary coolant system. Such inert gas may cause disturbance in reactivity and/or degradation of IHX performance, and therefore, the inert gas behaviors have to be investigated to ensure the stable operation of a fast reactor. The authors have developed a plant dynamics code SYRENA to simulate the concentration distributions of the dissolved gas and the bubbles in a fast reactor. In this study, the models in SYRENA code are improved to achieve accurate simulations. Moreover, new models are introduced to simulate the various bubble behaviors in liquid metal flows. To validate the improved models and the newly developed models, the inert gas behaviors in the large-scale sodium-cooled reactor are simulated. As a result, it is confirmed that the complicated bubble dynamics in each component can be simulated appropriately by SYRENA code.
Takata, Takashi*; Konaka, Yuji*; Yamaguchi, Akira*; Ito, Kei; Ohno, Shuji; Ohshima, Hiroyuki
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 7 Pages, 2014/11
In this paper, a model of bubble transport at entrance nozzle has been developed based on theoretical and computational methods. For this purpose, a three-dimensional analysis of dynamic bubbles behavior has been carried out by using one-way bubble tracking method which is specified to a bubble flow under a low void fraction. A commercial CFD tool, FLUENT Ver. 6.3.26 is used for three-dimensional flow field analyses. Then the gas accumulation at a high pressure plenum (HPP) of sodium-cooled fast rector has been quantitatively-assessed by implementing the developed model in SYRENA code. Furthermore, gas elimination (bubble removal) systems have been considered and the quantitatively-assessment has been carried out in order to investigate the effect of each measure to the accumulation of gas at the HPP.
Ito, Kei; Kunugi, Tomoaki*; Ohno, Shuji; Kamide, Hideki; Ohshima, Hiroyuki
Journal of Computational Physics, 273, p.38 - 53, 2014/09
Times Cited Count：17 Percentile：71.23(Computer Science, Interdisciplinary Applications)Koizumi, Yasuo*; Ote, Naosuke*; Kamide, Hideki; Ohno, Shuji; Ito, Kei
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 7 Pages, 2014/07
Harjo, S.; Hemmi, Tsutomu; Abe, Jun; Gong, W.; Nunoya, Yoshihiko; Aizawa, Kazuya; Ito, Takayoshi*; Koizumi, Norikiyo; Machiya, Shutaro*; Osamura, Kozo*
Materials Science Forum, 777, p.84 - 91, 2014/02
Times Cited Count：2 Percentile：72.7(Materials Science, Multidisciplinary)Takasaki, Koji; Yasumune, Takashi; Onishi, Takashi; Nakamura, Keisuke; Ishimi, Akihiro; Ito, Chikara; Osaka, Masahiko; Ono, Masashi*; Hatakeyama, Shuichi*; Takahashi, Hiroyuki*; et al.
JAEA-Research 2013-043, 33 Pages, 2014/01
JAEA-Research-2013-043.pdf:13.81MB
In the Fukushima Daiichi Nuclear Power Plant, it is assumed that the core fuels melted partially or wholly, and the normal technique of accounting for a fuel assembly is not applicable. Therefore, it is necessary to develop the transparent and rational technique of accounting in the process of collection and storage of fuel debris. In this research, an application of the superconducting phase Transition Edge Sensor microcalorimeter (TES microcalorimeter) is studied for the accounting of nuclear materials in the fuel debris. It is expected that the detailed information of nuclear materials and fission products in fuel debris is obtained by using a high-resolution characteristic of TES microcalorimeter. In this report, the principle of TES microcalorimeter, the measurement experiment using TES in JAEA, and the simulated calculation using the EGS5 code system are summarized.
Ito, Kei; Takata, Takashi*; Ohno, Shuji; Kogawa, Hiroyuki; Kamide, Hideki; Imai, Yasutomo*; Kawamura, Takumi*
Nihon Kikai Gakkai Rombunshu, B, 79(808), p.2630 - 2634, 2013/12
In a sodium-cooled fast reactor, inert gas exists in the primary coolant system as bubbles or dissolved gas. Similarly, small bubbles exist also in the mercury target loop in J-PARC to suppress cavitation erosion. To simulate these inert gas behaviors in liquid metal flows, the Japan Atomic Energy Agency (JAEA) has developed a plant dynamics code VIBUL. In this study, new models, i.e. the bubble release and bubble carry under models, are introduced to simulate the bubble behaviors in the fast reactor and mercury target system. Then, the small bubble behavior in the mercury target system is simulated to check the validity of the new models.
Ito, Kei; Ohno, Shuji; Kamide, Hideki; Kogawa, Hiroyuki; Futakawa, Masatoshi; Kawamura, Takumi*; Imai, Yasutomo*
JAEA-Research 2013-008, 117 Pages, 2013/10
JAEA-Research-2013-008.pdf:6.55MB
The Japan Atomic Energy Agency has been developed a plant dynamics code VIBUL to simulate the concentration distributions of the dissolved gas and the bubbles in a fast reactor. In this study, the VIBUL code is improved to achieve accurate simulations, e.g. rigorous mole conservation of inert gas. Moreover, new modles are introduced to simulate the small bubble behaviors in the J-PARC mercury target system. To validate the improved models and the newly developed models, the inert gas behaviors in the large-scale sodium-cooled reactor and the small bubble behaviors are simulated. As a result, it is confirmed that the complicated bubble dynamics in each component, e.g. core, IHX or surge tank, can be simulated appropriately by the VIBUL code.
Ito, Kei; Ezure, Toshiki; Ohno, Shuji; Kamide, Hideki; Nakamine, Yoshiaki*; Imai, Yasutomo*
JAEA-Research 2013-007, 75 Pages, 2013/10
JAEA-Research-2013-007.pdf:5.21MB
In Japan Atomic Energy Agency (JAEA), various thermal hydraulics phenomena in an upper plenum region are evaluated in the study on the safety design criteria of the sodium-cooled fast reactor in Japan (JSFR). The gas entrainment (GE) from a free surface of coolant and the vortex cavitation (VC) at the H/L intake are important phenomena to be evaluated. Since these phenomena occur by the significant pressure drop in the vicinity of a vortex center, a technique to evaluate a vortex behavior is indispensable. The authors are developing a GE evaluation method using a numerical analysis and a vortex model. In this study, the evaluations are performed on the GE behavior in the 1/1.8 scaled water model test. In addition, a VC evaluation method is proposed on the basis of the GE evaluation method. As a basic validation of the VC evaluation method, the basic sub-surface vortex test in JAEA is evaluated.
Ote, Naosuke*; Koizumi, Yasuo*; Kamide, Hideki; Ohno, Shuji; Ito, Kei
Proceedings of 21st International Conference on Nuclear Engineering (ICONE-21) (DVD-ROM), 7 Pages, 2013/07
A sodium-cooled fast breeder reactor is now at the developing stage in Japan. One concern for safety is cover gas entrainment into the sodium coolant. The gas entrainment rate into liquid by the vortex formed on the free surface was examined experimentally. Liquid flowed into a cylindrical vessel from a wall tangentially. Swirl flow was formed in the vessel, and then liquid drained from the bottom outlet of the vessel. A hollow vortex was formed on the free surface in the test vessel. Air was entrained under the free surface of the vortex and carried away from the bottom of the vessel. The flow state of the gas entrainment was visually observed by using a high speed video camera. The gas entrainment rate into liquid was measured. In the previous study, test fluid was water. Kerosene and 20 cSt silicone oil were newly introduced as the test fluid to examine the effect of the physical properties on the gas entrainment phenomena.
Ito, Kei; Ezure, Toshiki; Ohno, Shuji; Kamide, Hideki
Nihon Kikai Gakkai Rombunshu, B, 79(801), p.838 - 847, 2013/05
The prevention of vortex cavitation is one of key issues in the study on a large-scale sodium-cooled fast reactor in Japan (JSFR). In this paper, the theoretical modeling of an unsteady vortex cavitation is proposed. In this model, the cavitation behavior in a strong sub-surface vortex is calculated based on the axisymmetric unsteady Navier-Stokes (N-S) equation. Then, the cavitating radius is determined by comparison of the calculated pressure with vapor pressure. As a basic test of this model, vortex development and resulting cavitation are calculated. The results show that the growth of the cavitating region with the development of circumferential can be calculated.
Ito, Kei; Ezure, Toshiki; Ohno, Shuji; Kamide, Hideki
Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB Flash Drive), 11 Pages, 2013/05
The gas entrainment (GE) is one of important issues in the study on sodium-cooled fast reactors. In this paper, the authors propose a unified evaluation model of the bubble-type GE, which can predict the onset condition in various experiments. This evaluation model consists of two equations; one is the mechanical balance equation at the gas core tip, the other shows the ratio of the critical gas core length to the specific radius of the free surface vortex. To check the validity of the proposed model, several experiments, e.g. Baum's experiment, are evaluated. As a result, the model gives the similar onset conditions to the experimental results.
Wakai, Eiichi; Kim, B. J.; Nozawa, Takashi; Kikuchi, Takayuki; Hirano, Michiko*; Kimura, Akihiko*; Kasada, Ryuta*; Yokomine, Takehiko*; Yoshida, Takahide*; Nogami, Shuhei*; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 6 Pages, 2013/03
