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Nakajima, Norihiro; Nishida, Akemi; Matsubara, Hitoshi*; Hazama, Osamu*; Suzuki, Yoshio; Sawa, Kazuhiro; Iigaki, Kazuhiko

Transactions of 22nd International Conference on Structural Mechanics in Reactor Technology (SMiRT-22) (CD-ROM), 10 Pages, 2013/08

It is not convenient to experimentally analyze its behavior under strong loads of earthquakes, since the facility is extremely huge and complex. The proposed system performs numerical simulations to evaluate the behaviors of an assembly like a nuclear facility. This system projects the components of an assembly onto both/either a distributed and/or a parallel computing environment in order to conduct a simulation of the behavior of an assembly such as a nuclear facility. In a result discussion, a numerical experiment was carried out with a cantilever model and its result was compared with theoretical data. A good corresponding among them was obtained as a structural analysis of an assembly by using a parallel computer. As a conclusion, a suggested methodology has shown to calculate a behavior of an assembly with High Temperature engineering Test Reactor.

Suzuki, Yoshio; Nakajima, Norihiro; Araya, Fumimasa; Hazama, Osamu; Nishida, Akemi; Kushida, Noriyuki; Akutsu, Taku; Teshima, Naoya; Nakajima, Kohei; Kondo, Makoto; et al.

Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 9 Pages, 2008/05

Nishida, Akemi; Araya, Fumimasa; Matsubara, Hitoshi; Hazama, Osamu; Nakajima, Norihiro

Anzen Kenkyu Foramu 2008 Sanko Shiryoshu, p.93 - 94, 2008/02

The development of a vibration simulator has been planned for used in a full-scale nuclear power station; this simulator will implement the latest computational technologies and will allow comparisons to be made among the conventional spring-mass models and the actually observed data obtained from experiment and practice. This simulator will be used for evaluating the conservativeness of conventional models and the fragility of components through a seismic PSA (probabilistic safety assessment). This simulator will be used for analyzing the seismic responses of the entire nuclear facility by modeling each component independently.

Hazama, Osamu; Kushida, Noriyuki; Matsubara, Hitoshi; Nishida, Akemi; Suzuki, Yoshio; Araya, Fumimasa; Aoyagi, Tetsuo; Nakajima, Norihiro; Kondo, Makoto

Proceedings of 9th MpCCI User Forum, p.118 - 124, 2008/00

In order to safely and stably supply energy by nuclear means, structural integrity and design standards of the plant including factors such as aging must be confirmed, and its future conditions must be predicted with high reliability. Although full-scale experimentations are favorable for acquiring necessary information and carrying out investigative studies of the nuclear structures, such experiments are for most cases physically and financially impossible. Our objective is to establish an integrated full-scale simulation framework for simulating and quantitatively investing the vibration behavior of nuclear power plant equipments under earthquakes.

Nishida, Akemi; Matsubara, Hitoshi; Tian, R.; Hazama, Osamu; Suzuki, Yoshio; Araya, Fumimasa; Nakajima, Norihiro; Tani, Masayuki; Kondo, Makoto

Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(3), p.376 - 382, 2007/09

Unexpected accidents such as oil-tank fires caused by the earthquake and breakage of pipes of nuclear plants have occurred over the past several years. Higher reliability is thus now increasingly expected to maintain the safety of infrastructures. We have been intensely focused on the construction of an analysis system called the "three-dimensional virtual vibration testbed," which is a numerical simulation system for a nuclear plant which considers the interconnection of machines, pipes, buildings, and their foundations under real operating conditions. In this paper, the "part-wise analysis method" is proposed in which each structural component is treated independently and analyzed as an assembly structure. Further, the system configurations in a parallel distribution environment are described. This study shows one of the successful examples of the application of this method to a nuclear-plant cooling system that has tens of millions of degrees of freedom.

Hazama, Osamu; Araya, Fumimasa

Nihon Kikai Gakkai 2007-Nendo Nenji Taikai Koen Rombunshu, Vol.1, p.685 - 686, 2007/09

A new concept of double-wall-tube steam generator (SG) is being introduced and investigated as an innovative technology to realize next-generation sodium-cooled Fast Breeder Reactors (FBRs) for commercialization. This new concept is posing great challenges in the engineering design of a tubesheet which must bundle over 7000 double-wall tubes under severe mechanical and thermal loads. R&D efforts concerning the development of a feasible design and establishment of design-by-analysis methods for the new-concept tubesheet structure have been begun at JAEA. As a first step, an attempt at identifying the high stress locations and their magnitudes through large-scale numerical simulations using geometrical models in accord with reality are reported.

Tani, Masayuki; Nakajima, Norihiro; Nishida, Akemi; Suzuki, Yoshio; Matsubara, Hitoshi; Araya, Fumimasa; Kushida, Noriyuki; Hazama, Osamu; Kondo, Makoto; Kawasaki, Kozo

Proceedings of Joint International Topical Meeting on Mathematics & Computations and Supercomputing in Nuclear Applications (M&C+SNA 2007) (CD-ROM), 12 Pages, 2007/04

Hazama, Osamu; Suzuki, Yoshio; Matsubara, Hitoshi; Tian, R.; Nishida, Akemi; Tani, Masayuki; Nakajima, Norihiro

Proceedings of 7th MpCCI User Forum, p.132 - 136, 2006/00

Nuclear power plants are large in scale and functionally very complex structures. For safety precautions, they are maintained under very strict rules. Yet, no controlled experiments are possible to deal with full-scale nuclear reactors and its cooling systems in its entirety. In order to maintain the safety of these nuclear power plants against extra-large earthquakes and aging, Japan Atomic Energy Agency (JAEA) is currently constructing a fully three-dimensional virtual earthquake testbed on the ITBL Grid infrastructure. Currently, we have developed a high-performance finite element elastostatic simulation system based on component and part-wise assembly. Using the program, we were able to construct a finite element model of an experimental high-temperature gas reactor (HTGR) called HTTR, or High Temperature engineering Test Reactor.

Hazama, Osamu; Nakajima, Norihiro; Post, P.*; Wolf, K.*

Proceedings of 8th US National Congress on Computational Mechanics (USNCCM-8) (CD-ROM), 1 Pages, 2005/07

Computational science has always played an import role in nuclear engineering because it is quite difficult, if not impossible, to carry out experiments on the actual full-scale reactors in operation. We have been developing a numerical simulation infrastructure for carrying out numerical experiments on the virtual reactors constructed within computers. In order to understand the physical behavior of a reactor, interactions among various physial phenomena must be considered and understood. Therefore, a generic coupler has been developed to connect various software and hardware for the purposes of coupled simulations. Since this type of simulation requires large amount of computational resources, the coupler development is carried out on the ITBL GRID infrastructure. The development of this coupler and its applications to parallel and distributed coupled simulations with future development plans are reported.

Hazama, Osamu; Nakajima, Norihiro

Keisan Kogaku Koenkai Rombunshu, 10(1), p.259 - 260, 2005/05

It is impossible to carry out a controlled laboratory experiments on an operational full-scale power plant. Therefore, construction of a testbed to assess the safety of such systems by numerical means is believed to be meaningful. At CCSE/JAERI, a project to develop a numerical testbed to assess the safety of nuclear reactors have been begun. Simulations of such complex systems will inevitably require tremendous amount of computational resources. Therefore, the numerical testbed is constructed on the ITBL Grid middleware. A prototype of a generic software coupling interface was developed to couple various simulation software within the ITBL Grid environment to execute large-scale multi-disciplinary simulations on the testbed. This coupler and its application to some fluid-structure problems will be illustrated.

Hazama, Osamu; Nakajima, Norihiro

Proceedings of 6th MpCCI User Forum, p.76 - 77, 2005/05

In order to accurately solve complex physical phenomena, interactions of various phenomena must be considered, which makes simulations multi-disciplinary. We have been developing a virtual nuclear reactor simulator on the ITBL Grid infrastructure in order to assess the safety of the nuclear reactors. This simulator system allows for numerical experiments on the full-scale and fully operational virtual nuclear reactors which is not possible in real-life experiments. In order to clarify various complex physical phenomena within the reactors, multi-disciplinary simulations, which are computationally demanding, are required. We have been developing a software to allow concurrent use of arbitrary combination of hardware and software to realize a multi-disciplinary simulation system on the ITBL. We have used STAMPI, developed by CCSE/JAERI, and MpCCI, developed by Fraunhofer SCAI, to construct the system. The system is now functional on the ITBL and will be introduced.

Hazama, Osamu; Nakajima, Norihiro; Hirayama, Toshio; Post, P.*; Wolf, K.*

IWACOM, P. 161, 2004/11

The numerical methods and computational hardware of today allow for studies on multi-disciplinary simulations. We have been developing an "integrated numerical simulation system" to solve coupled simulation problems under meta-computing environments. The system aims to construct a competent coupler for carrying out multi-disciplinary simulations by allowing concurrent execution of arbitrary simulation codes on different computers in parallel. The effectiveness of this system infrastructure is illustrated through its applications to fluid-structure interactive problems.

Hazama, Osamu; Guo, Z.*

Keisan Kogaku Koenkai Rombunshu, 9(2), p.617 - 620, 2004/05

Although multi-disciplinary coupled simulations are considered important and necessary by many to reflect reality into the numerical simulations, there still exist many obstacles which inhibit such numerical simulations. There still exist very few software packages in the market which satisfy user needs in such numerical simulations. In many instances, self-development of software packages which allow for such coupled simulations will also be quite burdensome simply because considering multi-physics require more knowledge, experience, time . Parallel processing of the simulations will definitely be required to aquire meaningful coupled solutions within a given practical time. Under the international collaborative efforts between CCSE/JAERI and Fraunhofer SCAI, a generic code coupling mechanism and implementation are developed for multi-disciplinary simulation of continua in a meta-computing environment. Two libraries, STAMPI, by CCSE/JAERI, and MpCCI, by Fraunhofer SCAI, will be implemented together to allow such simulations.

Atanasiu, G. M.*; Hazama, Osamu; Guo, Z.; Yagawa, Genki*

Proceedings of 2nd International Conference Lifetime Oriented Design Concepts (ICLODC 2004), p.449 - 458, 2004/03

Some strategies in monitoring the structural seismic performance for a class of RC multistory buildings using linear and nonlinear dynamic analysis. New concepts and visions, considering the seismic input models based on probabilistic hazard level, will be presented. Numerical simulations of RC structures with different topologies are carried out as case studies, to search for a suitable strategy of seismic monitoring based on structural performance. For comparison, equivalent single degree of freedom models are also taken into account. The seismic input is based on the 1994 Northridge earthquake acceleration time histories. For comparison, the unscaled Kobe ground motion were also considered as input.

Hazama, Osamu; Guo, Z.

Proceedings of International Conference on Supercomputing in Nuclear Applications (SNA 2003) (CD-ROM), p.119 - 120, 2003/09

In order for the numerical simulations to reflect textquotedblleft real-worldtextquotedblright phenomena and occurrences, incorporation of multidisciplinary and multi-physics simulations considering various physical models and factors are becoming essential. However, there still exist many obstacles which inhibit such numerical simulations. For example, it is still difficult in many instances to develop satisfactory software packages which allow for such coupled simulations and such simulations will require more computational resources. A precise multi-physics simulation today will require parallel processing which again makes it a complicated process. Under the international cooperative efforts between CCSE/JAERI and Fraunhofer SCAI, a German institute, a library called the MpCCI, or Mesh-based Parallel Code Coupling Interface, has been implemented together with a library called STAMPI to couple two existing codes to develop an textquotedblleft integrated numerical simulation systemtextquotedblright intended for meta-computing environments.

Guo, Z.; Hazama, Osamu; Yamagiwa, Mitsuru; Hirayama, Toshio; Matsuzawa, Teruo*

Advances in computational & experimental engineering & sciences (CD-ROM), 6 Pages, 2003/07

no abstracts in English

Hazama, Osamu; Guo, Z.

Keisan Kogaku Koenkai Rombunshu, 8(2), p.759 - 760, 2003/05

no abstracts in English

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：52.06(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.

Matsubara, Hitoshi; Minami, Takahiro; Hazama, Osamu; Nishida, Akemi; Tian, R.; Nakajima, Norihiro; Tani, Masayuki

no journal, ,

A nuclear power plant is made up of numerous components. In previous techniques, structural analyses of entire nuclear power plant have not been achieved because it is assumed to be united structure. In this work, through our new model approach called the assembled-structure analysis, simulation of an entire nuclear power plant by assembling of individual components was made possible.

Suzuki, Yoshio; Kushida, Noriyuki; Yamagishi, Nobuhiro; Minami, Takahiro; Matsumoto, Nobuko; Nakajima, Kohei; Nishida, Akemi; Matsubara, Hitoshi; Tian, R.; Hazama, Osamu; et al.

no journal, ,

no abstracts in English