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Journal Articles

GPU-acceleration of locally mesh allocated two phase flow solver for nuclear reactors

Onodera, Naoyuki; Idomura, Yasuhiro; Ali, Y.*; Yamashita, Susumu; Shimokawabe, Takashi*; Aoki, Takayuki*

Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.210 - 215, 2020/10

This paper presents a GPU-based Poisson solver on a block-based adaptive mesh refinement (block-AMR) framework. The block-AMR method is essential for GPU computation and efficient description of the nuclear reactor. In this paper, we successfully implement a conjugate gradient method with a state-of-the-art multi-grid preconditioner (MG-CG) on the block-AMR framework. GPU kernel performance was measured on the GPU-based supercomputer TSUBAME3.0. The bandwidth of a vector-vector sum, a matrix-vector product, and a dot product in the CG kernel gave good performance at about 60% of the peak performance. In the MG kernel, the smoothers in a three-stage V-cycle MG method are implemented using a mixed precision RB-SOR method, which also gave good performance. For a large-scale Poisson problem with $$453.0 times 10^6$$ cells, the developed MG-CG method reduced the number of iterations to less than 30% and achieved $$times$$ 2.5 speedup compared with the original preconditioned CG method.

Journal Articles

In-vessel thermal-hydraulics analyses of the ASTRID-600MWe reactor with STAR-CCM+ code to supply boundary conditions for mechanical evaluation

Onoda, Yuichi; Chikazawa, Yoshitaka; Nakamura, Hironori*; Barbier, D.*; Dirat, J.-F.*

Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 8 Pages, 2019/05

no abstracts in English

Journal Articles

Communication avoiding multigrid preconditioned conjugate gradient method for extreme scale multiphase CFD simulations

Idomura, Yasuhiro; Ina, Takuya*; Yamashita, Susumu; Onodera, Naoyuki; Yamada, Susumu; Imamura, Toshiyuki*

Proceedings of 9th Workshop on Latest Advances in Scalable Algorithms for Large-Scale Systems (ScalA 2018) (Internet), p.17 - 24, 2018/11

 Times Cited Count:2 Percentile:77.41

A communication avoiding (CA) multigrid preconditioned conjugate gradient method (CAMGCG) is applied to the pressure Poisson equation in a multiphase CFD code JUPITER, and its computational performance and convergence property are compared against CA Krylov methods. In the JUPITER code, the CAMGCG solver has robust convergence properties regardless of the problem size, and shows both communication reduction and convergence improvement, leading to higher performance gain than CA Krylov solvers, which achieve only the former. The CAMGCG solver is applied to extreme scale multiphase CFD simulations with $$sim 90$$ billion DOFs, and it is shown that compared with a preconditioned CG solver, the number of iterations is reduced to $$sim 1/800$$, and $$sim 11.6times$$ speedup is achieved with keeping excellent strong scaling up to 8,000 nodes on the Oakforest-PACS.

Journal Articles

Dislocation density of GlidCop with compressive strain applied at high temperature

Sano, Mutsumi*; Takahashi, Sunao*; Watanabe, Atsuo*; Shiro, Ayumi*; Shobu, Takahisa

Materials Research Proceedings, Vol.2, p.609 - 614, 2017/00

Dislocation densities of GlidCop with compressive strain applied at high temperature were examined by X-ray line profile analyses with synchrotron radiation. In order to evaluate the dislocation density, we applied the modified Williamson-Hall and modified Warren-Averbach method. The dislocation densities of GlidCop with compressive strain from 0.011-0.04 were in the range of 5.7-8.0$$times$$10$$^{14}$$m$$^{-2}$$.

Journal Articles

A High-precision calculation method for interface normal and curvature on an unstructured grid

Ito, Kei; Kunugi, Tomoaki*; Ohno, Shuji; Kamide, Hideki; Ohshima, Hiroyuki

Journal of Computational Physics, 273, p.38 - 53, 2014/09

 Times Cited Count:12 Percentile:67.37(Computer Science, Interdisciplinary Applications)

Journal Articles

Actively-cooled plasma electrode for long pulse operations in a cesium-seeded negative ion source

Fujiwara, Yukio; Watanabe, Kazuhiro; Okumura, Yoshikazu; Trainham, R.*; Jacquot, C.*

Review of Scientific Instruments, 76(1), p.013501_1 - 013501_5, 2005/01

 Times Cited Count:0 Percentile:0.01(Instruments & Instrumentation)

A new actively-cooled plasma electrode has been developed for long pulse operation in a cesium-seeded negative ion source. To keep the electrode temperature at about 300 $$^{circ}$$C, which is optimum range of temperature to enhance cesium effects, the electrode cooling structure has been designed using three-dimensional numerical simulation assuming that the heat flux from the source plasma was 15 W/cm$$^{2}$$. Water cooling tubes were brazed to the plasma electrode substrate with spacers made of stainless steel which acts as a thermal resistance. The fabricated plasma electrode has been tested in a cesium-seeded volume negative ion source called Kamaboko source. The temperature of the electrode reached 280 $$^{circ}$$C for the arc power of 41 kW, which is operating condition required for producing D- beams with current densities exceeding 20 mA/cm$$^{2}$$. It was demonstrated that the actively-cooled plasma electrode is applicable to long pulse operations, meeting the temperature requirement for optimizing the surface-production process of negative ions in the cesium seeded ion source.

Journal Articles

Research and development of the visualization grid in ITBL project

Takeshima, Yuriko; Suzuki, Yoshio*; Matsumoto, Nobuko*; Sai, Kazunori*; Nakajima, Norihiro

Proceedings of 4th International Symposium on Advanced Fluid Information and Transdiciplinary Fluid Integration (AFI/TFI 2004), p.157 - 158, 2004/11

The Information-Technology-Based Laboratory (ITBL) project aims to construct a virtual research environment which shares intellectual resources such as the super computers by the grid computing, softwares and data in Japan and supports joint researches at a distance. In the project, two visualization systems: the PATRAS/ITBL and the AVS/ITBL have been developed. The feature of the PATRAS/ITBL is the collaborative, real-time visualization of data resulting from an execution of numerical simulations. The AVS/ITBL visualization system enables remote postprocessing visualization of any data stored on any supercomputer located in the ITBL network. The global structure and technologies of these systems are presented.

Journal Articles

Towards to realize a quake-proof information control and management system for nuclear power plant

Nakajima, Norihiro; Kimura, Hideo; Higuchi, Kenji; Aoyagi, Tetsuo; Suzuki, Yoshio; Hirayama, Toshio; Yagawa, Genki

Dai-23-Kai Nihon Shimyureshon Gakkai Taikai Happyo Rombunshu, p.117 - 120, 2004/06

The pablic acceptance of nuclear power plants operations requests information of status for the safety and ease. Previous technology in computational scinece is generarlly carried out the analysis as an uniform structure, although the plants are assembled by thousand of parts. The proposed approach is to develope assembled structural analysis and fluid/heat analyis in assembled structures under the natural and actual environmnet such as daily operation, small quakeing which does not induce shut down procedure, and so on.

Journal Articles

In the case of Japan Atomic Energy Research Institute

Azumi, Masafumi

Purazuma, Kaku Yugo Gakkai-Shi, 80(5), p.378 - 381, 2004/05

Progress of large scale scientific simulation environment in JAERI is briefly described. The expansion of fusion simulation science have been played a key role in the increasing performances of super computers and computer network system in JAERI. Both scalar parallel and vector parallel computer systems are now working in Naka and Tokai sites respectively and, particle and fluid simulation codes developed under the fusion simulation project, NEXT, are running on each system. The storage grid system has been also successfully developed for the effective visualization analysis by remote users. Fusion research is going to enter the new phase of ITER, and the need for the super computer system with higher performance are increasing more than as ever along with the development of reliable simulation models.

Journal Articles

Comopuational environment of Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute

Nakajima, Norihiro

Keisan Kogaku, 9(2), p.919 - 920, 2004/04

Comopuational environment is introduced in Japan Atomic Energy Research Institute. A mission of Center for Promotion of Computational Science and Engineering is also introduced and discussed the research and development theme. As next generation comopuational environment, ITBL as a grid computing system is summarized.

Journal Articles

Visualization system on ITBL

Suzuki, Yoshio

JAERI-Conf 2004-003, p.52 - 55, 2004/03

no abstracts in English

Journal Articles

20.8MHz electron gun system for an energy recovery linac FEL at JAERI

Nishimori, Nobuyuki; Hajima, Ryoichi; Kikuzawa, Nobuhiro; Minehara, Eisuke; Nagai, Ryoji; Sawamura, Masaru

Proceedings of 3rd Asian Particle Accelerator Conference (APAC 2004), p.625 - 627, 2004/00

no abstracts in English

Journal Articles

Application of ITBL basic software for virtual organizations

Higuchi, Kenji; Otani, Takayuki; Hasegawa, Yukihiro*; Suzuki, Yoshio; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Maesako, Hiroshi*; Fukuda, Masahiro; Yagawa, Genki

Keisan Kogaku Koenkai Rombunshu, 8(2), p.797 - 800, 2003/05

no abstracts in English

Journal Articles

Visualization systems on the Information-Technology-Based Laboratory

Suzuki, Yoshio; Sai, Kazunori*; Matsumoto, Nobuko*; Hazama, Osamu

IEEE Computer Graphics and Applications, 23(2), p.32 - 39, 2003/04

 Times Cited Count:6 Percentile:53.15(Computer Science, Software Engineering)

Visualization systems PATRAS/ITBL and AVS/ITBL, which are based on visualization software PATRAS and AVS/Express respectively, have been developed on a global, heterogeneous computing environment, called Information Technology Based Laboratory (ITBL). PATRAS/ITBL allows for real-time visualization of the numerical results acquired from coupled multi-physics numerical simulations, executed on different hosts situated in remote locations. A collaborative visualization among numerous sites for this type of simulation was also made possible. AVS/ITBL allows for post processing visualization. The scientific data located in remote sites may be selected and visualized on web browser installed in a user terminal. The global structure and main functions of these systems are presented.

JAEA Reports

Effect of electrode materials on a negative ion production in a cesium seeded negative ion source

Shimizu, Takashi; Morishita, Takatoshi; Kashiwagi, Mieko; Hanada, Masaya; Iga, Takashi*; Inoue, Takashi; Watanabe, Kazuhiro; Wada, Motoi*; Imai, Tsuyoshi

JAERI-Tech 2003-006, 26 Pages, 2003/03


no abstracts in English

Journal Articles

Development of multiple job execution and visualization system on ITBL system infrastructure software and its utilization for parametric studies in environmental modeling

Suzuki, Yoshio; Matsumoto, Nobuko*; Yamagishi, Nobuhiro*; Higuchi, Kenji; Otani, Takayuki; Nagai, Haruyasu; Terada, Hiroaki; Furuno, Akiko; Chino, Masamichi; Kobayashi, Takuya

Computational Science - ICCS 2003, International Conference Saint Petersburg Russian Federation, Melbourne Australia, June 2-4, 2003 Proceedings, p.120 - 129, 2003/00

Information-Technology Based Laboratory (ITBL) project has been propelled as one of e-Japan priority policy programs. The purposes of the project are to share intellectual resources such as remote computers, programs and data in universities and institutes and to support cooperative studies among researchers, building a virtual research environment, ITBL. Japan Atomic Energy Research Institute (JAERI) has been working on installation and management of hardware and development of infrastructure software and applications. As application software, researches on quantum bioinformatics and environmental sciences are carried out. This paper presents utilization of ITBL system infra-structure software for 'Numerical Environment System' which is developed for environmental studies. More effective job executions and visualization are ex-pected by using Task Mapping Editor (TME) and AVS/ITBL, which are tools developed as infrastructure software.

Journal Articles

Visualization grid in nuclear research

Suzuki, Yoshio

Dai-9-Kai Bijuarizeshon, Kanfarensu Rombunshu (Internet), 7 Pages, 2003/00

no abstracts in English

Journal Articles

Grid computing supporting system on ITBL project

Higuchi, Kenji; Imamura, Toshiyuki*; Suzuki, Yoshio; Shimizu, Futoshi; Machida, Masahiko; Otani, Takayuki; Hasegawa, Yukihiro*; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Aoyagi, Tetsuo; et al.

Lecture Notes in Computer Science 2858, p.245 - 257, 2003/00

Prototype of the middleware for Grid project promoted by national institutes in Japan has been developed. Key technologies that are indispensable for construction of virtual organization were already implemented onto the prototype of middleware and examined in practical computer/network system from a view point of availability. In addition several kinds of scientific applications are being executed on the prototype system. It seems that successful result in the implementation of those technologies such as security infrastructure, component programming and collaborative visualization in practical computer/network systems means significant progress in Science Grid in Japan.

Journal Articles

Development of a virtual research environment in ITBL project

Higuchi, Kenji; Otani, Takayuki; Hasegawa, Yukihiro*; Suzuki, Yoshio; Yamagishi, Nobuhiro*; Kimura, Kazuyuki*; Aoyagi, Tetsuo; Nakajima, Norihiro; Fukuda, Masahiro; Imamura, Toshiyuki*; et al.

Proceedings of International Conference on Supercomputing in Nuclear Applications (SNA 2003) (CD-ROM), 11 Pages, 2003/00

An experimental application of Grid computing was executed in ITBL project promoted by six member institutes of MEXT. Key technologies that are indispensable for construction of virtual organization were implemented onto ITBL Middleware and examined in the experiment from a view point of availability. It seems that successful result in the implementation and examination of those technologies such as security infrastructure, component programming and collaborative visualization in practical computer/network systems means significant progress in Science Grid in Japan.

JAEA Reports

Experimental result of BWR post-CHF tests; Critical heat flux and post-CHF heat transfer coefficient (Contract research)

Iguchi, Tadashi; Iwaki, Chikako*; Anoda, Yoshinari

JAERI-Research 2001-060, 91 Pages, 2002/02


no abstracts in English

49 (Records 1-20 displayed on this page)