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Center for Computational Science & e-Systems
JAEA-Evaluation 2023-001, 38 Pages, 2023/07
Research on advanced computational science for nuclear applications, based on "the plan to achieve the medium- and long-term goal of the Japan Atomic Energy Agency", has been performed by Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of external experts and authorities which evaluates and advises toward the future research and development. This report summarizes the results of the R&D performed by CCSE in FY2022 (April 1st, 2022 - March 31st, 2023) and their evaluation by the committee.
Center for Computational Science & e-Systems
JAEA-Evaluation 2022-004, 38 Pages, 2022/11
Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid- and long-term goal of the Japan Atomic Energy Agency", has been performed by Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of external experts and authorities which evaluates and advises toward the future research and development. This report summarizes the results of the R&D performed by CCSE in FY2021 (April 1st, 2021 - March 31st, 2022) and their evaluation by the committee.
Center for Computational Science & e-Systems
JAEA-Evaluation 2022-003, 61 Pages, 2022/11
Japan Atomic Energy Agency (hereinafter referred to as "JAEA") consults an assessment committee, "Evaluation Committee of Research Activities for Computational Science and Technology Research" (hereinafter referred to as "Committee") for result and in-advance evaluation of "Computational Science and Technology Research", in accordance with "General Guideline for the Evaluation of Government Research and Development (R&D) Activities" by Cabinet Office, Government of Japan, "Guideline for Evaluation of R&D in Ministry of Education, Culture, Sports, Science and Technology" and "Regulation on Conduct for Evaluation of R&D Activities" by the JAEA. In response to the JAEA's request, the Committee assessed the research program of the Center for Computational Science and e-Systems (hereinafter referred to as "CCSE"). The Committee evaluated the management and research activities of the CCSE based on explanatory documents prepared by the CCSE, and oral presentations with questions-and answers.
Center for Computational Science & e-Systems
JAEA-Evaluation 2021-001, 66 Pages, 2021/11
Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid- and long-term goal of the Japan Atomic Energy Agency", has been performed by Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of external experts and authorities which does research evaluation and advice for the assistance of the future research and development. This report summarizes the results of the R&D performed by CCSE in FY2020 (April 1st, 2020 - March 31st, 2021), the results expected at the end of the 3rd mid and long-term goal period, and the evaluation by the committee on them.
Center for Computational Science & e-Systems
JAEA-Evaluation 2020-002, 37 Pages, 2020/12
Research on advanced computational science for nuclear applications, based on "the plan to achieve the mid and long term goal of the Japan Atomic Energy Agency", has been performed at Center for Computational Science & e-Systems (CCSE), Japan Atomic Energy Agency. CCSE established a committee consisting of outside experts and authorities which does research evaluation and advice for the assistance of the future research and development. This report summarizes the results of the R&D performed at CCSE in FY2019 (April 1st, 2019 - March 31st, 2020) and the evaluation by the committee on them.
Nakayama, Hiromasa; Nagai, Haruyasu
JAEA-Data/Code 2015-026, 37 Pages, 2016/03
We developed LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation (LOHDIM-LES). This dispersion model is designed based on LES which is effective to reproduce unsteady behaviors of turbulent flows and plume dispersion. The basic equations are the continuity equation, the Navier-Stokes equation, and the scalar conservation equation. Buildings and local terrain variability are resolved by high-resolution grids with of a few meters and these turbulent effects are represented by immersed boundary method. In simulating atmospheric turbulence, boundary layer flows are generated by a recycling turbulent inflow technique in a driver region set up at the upstream of the main analysis region. This turbulent inflow data are imposed at the inlet of the main analysis region. By this approach, the LOHDIM-LES can provide detailed information on wind velocities and plume concentration in the investigated area.
Takase, Kazuyuki; Yoshida, Hiroyuki; Akimoto, Hajime; Ose, Yasuo*; Aoki, Takayuki*
Nihon Kikai Gakkai 2005-Nendo Nenji Taikai Koen Rombunshu, Vol.7, p.17 - 18, 2005/09
no abstracts in English
Ueshima, Yutaka
PSE Book, p.69 - 82, 2005/03
no abstracts in English
Takase, Kazuyuki; Yoshida, Hiroyuki; Ose, Yasuo*; Akimoto, Hajime
WIT Transactions on Engineering Sciences, Vol.50, p.183 - 192, 2005/00
no abstracts in English
Yoshida, Hiroyuki; Nagayoshi, Takuji*; Ose, Yasuo*; Takase, Kazuyuki; Akimoto, Hajime
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.233 - 241, 2004/09
When there are no experimental data such as the reduced-moderation water reactor (RMWR), therefore, it is very difficult to obtain highly precise predictions. The RMWR core adopts a hexagonal tight lattice arrangement with about 1 mm gap between adjacent fuel rods. In the core, there is no sufficient information about the effects of the gap spacing and grid spacer configuration on the flow characteristics. Thus, we start to develop a predictable technology for thermal-hydraulic performance of RMWR core using advanced numerical simulation technology. As part of this technology development, we are developing advanced interface tracking method to improve conservation of volume of fluid. In this paper, we describe a newly developed interface tracking method and examples of the numerical results. In the present results, the error of volume conservation in the bubbly flow is within 0.6%.
Takase, Kazuyuki; Yoshida, Hiroyuki; Tamai, Hidesada; Ose, Yasuo*
Nihon Kikai Gakkai 2004-Nendo Nenji Taikai Koen Rombunshu, Vol.2 (No.04-1), p.251 - 252, 2004/09
no abstracts in English
Isogai, Kentaro*
JAERI-Data/Code 2003-010, 28 Pages, 2003/08
In these days, a large scale simulation by supercomputers has been prevailent in various fields of research and development. In such computations, however, there may be an excessively needless amount of work for researchers. This is due to such various facts such as that due to the development of high performance of supercomputers, too much data or too large a variety of data have become possible to treat, or the management of input or output data has become inadequate or improper in circumstances such as setting the environment of input parameters, missing computational results, and information processing which are common experiences among researchers.Therefore, we have been engaged in the construction of an integrated management system of input & output data in supporting a distributed computational system for large scale simulations for a variety of researchers as a common utility. In this article, the introduction of the distributed computing system, especially the explanation of the control server in it is described.
Sasa, Narimasa; Machida, Masahiko; Yamada, Susumu; Arakawa, Chuichi
Keisan Kogaku Koenkai Rombunshu, 7(1), p.171 - 172, 2002/05
Algebraic Multi Grid(AMG) is applied to solve the Ginzburg-Landau equations for Superconductors. The method effectively solves large scale linear algebraic equations. AMG is also applicable for systems with complex boundary condition in contrast with usual Geometrical Multi Grid.
Suzuki, Yoshio; Kishimoto, Yasuaki; NEXT Group
Purazuma, Kaku Yugo Gakkai-Shi, 78(1), p.59 - 69, 2002/01
From the year 2000 to 2001, the computer system located on Naka Fusion Research Establishment, Japan Atomic Energy Research Institute has been replaced. Since the main computer is the scalar parallel computer, which is about 40 times superior to the previous one, the amount of data outputted from the numerical simulations becomes much larger. In this paper, which scientific visual analysis system is more useful to extract the physical phenomena from such a large amount of data is investigated and the performance of the established visual analysis system is estimated.
Onuki, Akira; Akimoto, Hajime
Proc. of 1st European-Japanese Two-phase Flow Group Meeting, p.1 - 8, 1998/00
no abstracts in English