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Satoh, Daiki; Nakayama, Hiromasa; Furuta, Takuya; Yoshihiro, Tamotsu*; Sakamoto, Kensaku
PLOS ONE (Internet), 16(1), p.e0245932_1 - e0245932_26, 2021/01
Times Cited Count：2 Percentile：31.78(Multidisciplinary Sciences)In this study, we developed a simulation code named SIBYL, which estimates external gamma-ray doses at ground level from radionuclides distributed nonuniformly in atmosphere and on ground. SIBYL can combine with the local-scale atmospheric dispersion model LOHDIM-LES, and calculate the dose distributions according to the map of the activity concentrations simulated by LOHDIM-LES. To apply the SIBYL code to emergency responses of nuclear accidents, the time-consuming three-dimensional radiation transport simulations were performed in advance using the general-purpose Monte Carlo code PHITS, and then the results were compiled to the database for the SIBYL's dose calculations. Moreover, SIBYL can consider the dose attenuation by obstacles and the changes of terrain elevations. To examine the accuracy of SIBYL, typical five cases including 
Kr emission from a ventilation shaft and 
Cs dispersion inside urban area were investigated. The results of SIBYL agreed within 10% with those of PHITS at the most of target locations. Furthermore, the calculation speed was approximately 100 times faster than that of PHITS.
Suzuki, Yoshio; Otani, Takayuki; Sakamoto, Kensaku; Takakura, Masahiro*; Kuwabara, Yasuhiro*
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.287 - 294, 2020/10
HPC Technology Promotion Office, Center for Computational Science and e-systems (CCSE) of Japan Atomic Energy Agency (JAEA) is responsible for the administration of computer programs (CPs) and databases (DBs) developed in JAEA to disseminate R&D results in JAEA to the outside and improve R&D efficiency. The information of these CPs and DBs can be found using Program and Database retrieval System (PRODAS) (https://prodas.jaea.go.jp), which is developed by our team. Those in Japan can also obtain CPs and DBs in the nuclear field possessed in OECD NEA Data Bank (NEADB), Radiation Safety Information Computational Center (RSICC) in the United States, and International Atomic Energy Agency (IAEA). In this paper, the recent situation of possession and dispatch of CPs and DBs developed within JAEA and the frameworks to obtain and provide CPs and DBs in nuclear field worldwide are presented.
Kitamura, Tatsuaki*; Sakamoto, Kensaku; Takase, Kazuyuki
Kashika Joho Gakkai-Shi, 35(Suppl.2), p.59 - 60, 2015/09
no abstracts in English
Segawa, Mariko; Oi, Motoki; Kai, Tetsuya; Shinohara, Takenao; Kureta, Masatoshi; Sakamoto, Kensaku; Imaki, Tadashi*
Nuclear Instruments and Methods in Physics Research A, 769, p.97 - 104, 2015/01
Times Cited Count：2 Percentile：17.57(Instruments & Instrumentation)Kitamura, Tatsuaki*; Sakamoto, Kensaku; Takase, Kazuyuki
Nihon Kikai Gakkai Dai-27-Kai Keisan Rikigaku Koenkai Rombunshu (CD-ROM), 2 Pages, 2014/11
no abstracts in English
Shamoto, Shinichi; Kodama, Katsuaki; Imaki, Tadashi*; Nakatani, Takeshi; Oshita, Hidetoshi*; Kaneko, Naokatsu*; Masuko, Kenji*; Sakamoto, Kensaku; Yamaguchi, Kenji; Suzuya, Kentaro; et al.
JPS Conference Proceedings (Internet), 1, p.014011_1 - 014011_5, 2014/03
2D neutron diffraction imaging of an ammonite fossil was carried out at high-intensity total diffractometer NOVA in J-PARC. Observed diffraction profiles consist of calcite, siderite and amorphous structures.
Sakamoto, Kensaku; Hoshi, Yoshiyuki*
JAEA-Testing 2013-002, 80 Pages, 2013/11
JAEA-Testing-2013-002.pdf:8.37MB
On research and development of various fields of nuclear energy, visualization of calculated data is especially useful to understand the result of simulation in an intuitive way. Many researchers who run simulations on the supercomputer in Japan Atomic Energy Agency (JAEA) are used to transfer calculated data files from the supercomputer to their local PCs for visualization. In recent years, as the size of calculated data has gotten larger with improvement of supercomputer performance, reduction of visualization processing time as well as efficient use of JAEA network is being required. As a solution, we introduced a remote visualization system which has abilities to utilize parallel processors on the supercomputer and to reduce the usage of network resources by transferring data of intermediate visualization process. This paper reports a study on the performance of image processing with the remote visualization system. The visualization processing time is measured and the influence of network speed is evaluated by varying the drawing mode, the size of visualization data and the number of processors. Based on this study, a guideline for using the remote visualization system is provided to show how the system can be used effectively. An upgrade policy of the next system is also shown.
Kitamura, Tatsuaki*; Sakamoto, Kensaku; Takase, Kazuyuki
Nihon Kikai Gakkai Dai-26-Kai Keisan Rikigaku Koenkai Rombunshu (CD-ROM), p.703_1 - 703_2, 2013/11
no abstracts in English
Seki, Yohji; Ezato, Koichiro; Yokoyama, Kenji; Enoeda, Mikio; Kubota, Jinichi*; Sakamoto, Kensaku
Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 8 Pages, 2012/12
Japan Atomic Energy Agency has been performing R&D and design of a blanket module of a nuclear fusion reactor. Pebbles of a ceramic tritium breeder are packed in a container of the blanket. Helium purge gas is applied as a transport fluid in a tritium recovery system. Prediction of the flow phenomena with a tritium transfer is important for designs of the container. A purpose of our research is to establish and verify a method for a prediction of the flow in the pebble bed. In this study, pressure drops of the helium purge gas through the pebble bed were measured up to 100 L/min of flow rate. Reliability of prediction ability of the pressure drop was validated by this experiment within the flow rate which is less than 40 L/min. A numerical simulation for the flow field through the pebble bed also has been performed. Consequently, the velocity distributions are quantitatively and qualitatively obtained at near the wall and the center region in the pebble bed.
Suzuki, Yoshio; Hoshi, Yoshiyuki*; Sakamoto, Kensaku; Nakajima, Norihiro
Proceedings of 4th International Conference on Computational Methods (ICCM 2012) (USB Flash Drive), 9 Pages, 2012/11
We research and develop a three-dimensional vibration simulator for an entire nuclear plant aiming at technical advances for more rational safety assessment of nuclear plant under an earthquake. The simulator includes "an entire structural simulation of ground-building-equipments (beam model)" and "an assembly structural simulation of parts to equipments (solid model)". As one approach to examine the quality of solid model which consists of thousands of parts, we have established a trial tool to perform the assembly structural simulation for a small number of parts by zooming in on a part of equipments in the entire structural simulation, and to compare results. To verify the tool, we applied the tool to static and dynamic simulations for a cantilever with various cross sections, and a static simulation of a small number of parts of nuclear plant, and confirmed results for solid model well coincide with those for beam model.
Kitamura, Tatsuaki*; Sakamoto, Kensaku; Takase, Kazuyuki
Kashika Joho Gakkai-Shi, 32(Suppl.2), p.239 - 240, 2012/10
In the thermal-hydraulic design of supercritical water-cooled reactors, it is required to establish a thermal-hydraulic analysis method which can simulate the heat transfer and fluid flow characteristics of supercritical fluids precisely. A crossing flow is a phenomenon in which the fluid flowing through the inside of a fuel bundle in the perpendicular direction moves between subchannels to a transverse direction. The crossing flow influences the removal heat of a reactor core greatly. In the present study, results of the preliminary crossing flow simulation are described.
Kamiya, Kensaku; Honda, Mitsuru; Miyato, Naoaki; Urano, Hajime; Yoshida, Maiko; Sakamoto, Yoshiteru; Matsunaga, Go; Oyama, Naoyuki; Koide, Yoshihiko; Kamada, Yutaka; et al.
Nuclear Fusion, 52(11), p.114010_1 - 114010_12, 2012/10
Times Cited Count：10 Percentile：40.83(Physics, Fluids & Plasmas)Depending on the direction of the external tangential momentum input, substantial changes in not only toroidal but also poloidal flows for the carbon impurity ions are observed at around the 
-well region. The shear in the edge becomes wider in the co-NBI case, while the edge -well becomes deeper in the counter-NBI case.
Ida, Katsumi*; Kamiya, Kensaku; Isayama, Akihiko; Sakamoto, Yoshiteru; JT-60 Team
Physical Review Letters, 109(6), p.065001_1 - 065001_4, 2012/08
Times Cited Count：43 Percentile：84.34(Physics, Multidisciplinary)The transport inside the magnetic island is investigated in the plasma during the transient phase after the back transition from 
-mode to 
-mode, where a sudden drop of temperature outside the magnetic island causes a peaking of ion temperature at the 
-point inside the magnetic island.
Seki, Yohji; Yoshikawa, Akira; Tanigawa, Hisashi; Hirose, Takanori; Ezato, Koichiro; Enoeda, Mikio; Sakamoto, Kensaku
Dai-17-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.265 - 266, 2012/06
In the case of a water cooled ceramic breeder in a blanket, pebbles of a ceramic tritium breeder are packed in a container constituted by a partition plate. Helium purge gas is applied as a transport fluid in a tritium recovery system. It is of importance to build database of a pressure drop as part of a design of the tritium recovery system. In this experimental study, the pressure drops of He gas through pebble bed were measured within the wide range of a flow rate up to 100 L/min. The results indicate that a laminar flow is dominant and the pressure drop was correctly predicted by the empirical equation within a part of flow rate. Reliability of prediction ability of pressure drop was established by this experiment within the flow rate which is less than 60 L/min. Moreover, this paper describes that slight difference between the experimental result and the empirical equation within a range of flow rate from 60 L/min to 100 L/min.
Sakamoto, Kensaku; Shimizu, Futoshi; Tsuruoka, Takuya*; Nemoto, Toshiyuki*; Ishikawa, Naota*
JAEA-Testing 2011-005, 88 Pages, 2011/11
JAEA-Testing-2011-005.pdf:5.16MB
A new supercomputer system was deployed at JAEA in March 2010. The system is mainly composed of a large scale Linux cluster system (PRIMERGY BX900: 200Tflops) and a lead off system of RIKEN's K computer (FX1: 12Tflops), whose purposes are to deliver a high-performance parallel computing environment and application code development environment for the K computer, respectively. In this report, we present results of the evaluation of fundamental performance of the system.
Urano, Hajime; Saibene, G.*; Oyama, Naoyuki; Parail, V.*; de Vries, P.*; Sartori, R.*; Kamada, Yutaka; Kamiya, Kensaku; Loarte, A.*; L
nnroth, J.*; et al.
Nuclear Fusion, 51(11), p.113004_1 - 113004_10, 2011/11
Times Cited Count：10 Percentile：41.01(Physics, Fluids & Plasmas)The effect of TF ripple on the edge pedestal characteristics are examined in JET and JT-60U. By the installation of ferritic inserts, TF ripple was reduced from 
to 
in JT-60U. In JET, TF ripple was varied from 
to by feeding different currents to TF coils. The pedestal pressure was similar with reduced ripple in JT-60U. In JET, no clear difference of the pedestal characteristics was also observed. The edge toroidal rotation clearly decreased in counter direction by increased TF ripple. However, in JT-60U, the ELM frequency decreased by 
and the increased ELM loss power by 
with reduced ripple. In JET, ELM frequency increases only slightly with increased TF ripple. From this inter-machine experiment, TF ripple less than does not strongly affect the pedestal pressure. The effect of TF ripple on pedestal characteristics at lower collisionality close to ITER should be investigated as a next step study.
Kamiya, Kensaku; Sakamoto, Yoshiteru; Matsunaga, Go; Kojima, Atsushi; Urano, Hajime; Oyama, Naoyuki; Koide, Yoshihiko; Kamada, Yutaka; Ida, Katsumi*; Kurki-Suonio, T.*; et al.
Nuclear Fusion, 51(5), p.053009_1 - 053009_3, 2011/05
Times Cited Count：13 Percentile：49.44(Physics, Fluids & Plasmas)We revisited to measure the edge impurity ion dynamic with new CXRS in the hot ion H-mode regime at the high magnetic field having two steps transition where a jump of Ti gradient precedes a jump of impurity Vp. Two discrete phases with different magnitude of Er in the H-phase have been observed. One is the intermediate H-phase having a large Ti gradients without significant Vp of impurity species with moderate magnitude of Er, and the other is the complete H-phase characterized by a large Er.
Sueoka, Michiharu; Sakamoto, Kensaku; Shigemori, Yuji*
Heisei-22-Nendo Kumamoto Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 6 Pages, 2011/03
no abstracts in English
plasmasMatsunaga, Go; Aiba, Nobuyuki; Shinohara, Koji; Sakamoto, Yoshiteru; Takechi, Manabu; Suzuki, Takahiro; Asakura, Nobuyuki; Isayama, Akihiko; Oyama, Naoyuki; Yoshida, Maiko; et al.
Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03
Shimizu, Futoshi; Sakamoto, Kensaku; Yoshioka, Yuji*
FAPIG, (182), p.26 - 29, 2011/02
no abstracts in English
