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Maruyama, Shuhei
Proceedings of International Conference on Physics of Reactors 2022 (PHYSOR 2022) (Internet), 10 Pages, 2022/05
This paper proposes a new homogenization method, "Boundary Condition Free Homogenization (BCFH)". The traditional homogenization method separates the core calculation and the cell (assembly) calculation by assuming a specific boundary condition or a peripheral region in the cell calculation. Nevertheless, there are ambiguities and approximation in these assumptions, and they can also cause a decline in accuracy. BCFH aims to avoid these problems and improve the accuracy in the cell calculation such as homogenization. We imposed the conditions that the physical quantities in the cell related to the reaction rate preservation is preserved for any incoming partial current, during the homogenization. That is, the response matrices of cell average (or total) flux and outgoing partial current, to be the same form between heterogeneous and homogeneous system. As a result, homogenized parameters, such as cross-sections, superhomgenization factors, and discontinuity factors, are no longer dependent on a specific boundary condition. The new homogenized parameters obtained in this way are extended from the conventional vector form to the matrix form in BCFH. To investigate the performance of BCFH, numerical tests are done for the simplified models which originates in 750MW-class sodium-cooled fast reactor with MOX fuel core in Japan. It is found that BCFH is particularly effective in evaluating control rod reactivity worth and reaction rate distribution, compared to the traditional method. We conclude that the BCFH can be a promising homogenization concept for core neutronic analysis.
Ichihara, Yoshitaka*; Nakamura, Naohiro*; Moritani, Hiroshi*; Horiguchi, Tomohiro*; Choi, B.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 21(1), p.1 - 14, 2022/03
In this study, we aim to approximately evaluate the effect of nonlinearity of reinforced concrete structures through seismic response analysis using the equivalent linear analysis method. A simulation analysis was performed for the ultimate response test of the shear wall of the reactor building used in an international competition by OECD/NEA in 1996. The equivalent stiffness and damping of the shear wall were obtained from the trilinear skeleton curves proposed by the Japan Electric Association and the hysteresis curves proposed by Cheng et al. The dominant frequency, maximum acceleration response, maximum displacement response, inertia force-displacement relationship, and acceleration response spectra of the top slab could be simulated well up to a shear strain of approximately 
=2.0
10
. The equivalent linear analysis used herein underestimates the maximum displacement response at the time of ultimate fracture of approximately =4.010. Moreover, the maximum shear strain of the shear wall could not capture the locally occurring shear strain compared with that of the nonlinear analysis. Therefore, when employing this method to evaluate the maximum shear strain and test results, including those during the sudden increase in displacement immediately before the fracture, sufficient attention must be paid to its applicability.
Maeda, Makoto; Furutaka, Kazuyoshi; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Toh, Yosuke
Journal of Nuclear Science and Technology, 56(7), p.617 - 628, 2019/07
Times Cited Count：3 Percentile：31.89(Nuclear Science & Technology)Kawabata, Kuniaki; Yamada, Taichi; Shirasaki, Norihito; Ishiyama, Hiroki
Proceedings of IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM 2019) (USB Flash Drive), p.559 - 564, 2019/07
Kawatsuma, Shinji; Asama, Hajime*
Nihon Robotto Gakkai-Shi, 34(8), p.552 - 557, 2016/10
There was not a guideline available for researchers, developers or users for robots or heavy construction machines on the evaluation of radiation tolerance and management method of robots and heavy construction machines using semiconductors, like as CPUs on the shelf, under radiation condition, when Fukushima Daiichi NPPs accidents occurred on March 11th, 2011. The evaluation and the management method became necessary, in order to deploy robots like as QUINCE developing for big city accidents or unmanned heavy construction machines for landside disaster. According to "radiation tolerance data base on parts or materials" developed in 1980's to 1990's by Japan Atomic Energy Agency (JAEA), a guideline, for robots and unmanned heavy construction machines, was tentatively developed.
Tokuda, Shinji
Purazuma, Kaku Yugo Gakkai-Shi, 78(9), p.913 - 924, 2002/09
An introductory review is given on recent developments in the methods for stability analysis of a toroidally confined plasma. Emphasis is put on the perturbation analysis of a magnetohydrodynamic system that has the marginally stable state as a terminal point of continuous spectra. We address ourselves to the asymptotic matching method pertinent to such a problem. The Newcomb equation and inner-layer equations are essential ingredients in the methods and the numerical methods for solving them are discussed.
Oishi, Tetsuya; Yoshida, Makoto
Journal of Nuclear Science and Technology, 38(12), p.1115 - 1119, 2001/12
no abstracts in English
Kim, E.; Endo, Akira; Yamaguchi, Yasuhiro; Yoshizawa, Michio; Nakamura, Takashi*; Shiomi, T.*
Proceedings of 10th International Congress of the International Radiation Protection Association (IRPA-10) (CD-ROM), 6 Pages, 2000/05
no abstracts in English
Ishigami, Tsutomu; Kobayashi, Kensuke
Journal of Nuclear Science and Technology, 35(6), p.443 - 453, 1998/06
Times Cited Count：1 Percentile：15.03(Nuclear Science & Technology)no abstracts in English
Suzuki, Motoe
JAERI-Research 94-022, 36 Pages, 1994/10
JAERI-Research-94-022.pdf:1.28MB
no abstracts in English
Saito, Kimiaki; Moriuchi, Shigeru
JAERI 1306, 121 Pages, 1987/08
no abstracts in English
; ; ; *; *; *
Nucl.Eng.Des., 74(3), p.325 - 337, 1982/00
Times Cited Count：0 Percentile：0.02(Nuclear Science & Technology)no abstracts in English
; *
JAERI-M 8919, 44 Pages, 1980/07
no abstracts in English
;
JAERI-M 6952, 25 Pages, 1977/02
no abstracts in English
Kawatsuma, Shinji
no journal, ,
Japan Atomic Energy Agency has just started up NARAHA Remote Technology Development Center equipped with UUV testing pool, Mockup Stairs, Motion capture, etc. The center would support development of robots for decommissioning and emergency response. In the course of the support, JAEA is also developing Robot simulator and Standard testing method.
Morishita, Masaki; Otani, Akihito*
no journal, ,
The JSME Code Case N-CC-008 provides design rules for piping seismic design by inelastic response analysis and strain-based fatigue criteria. The Code Case uses the Rainflow method for cycle counting. The Rainflow method is used for identifying pairs of peaks/valleys of the representative strain and their occurrence times. On the other hand, ASME Code reads "The Rainflow cycle counting method is recommended but not applicable for non-proportional loading." The authors analyzed the behavior of multi-axial strain of piping systems to test the non-proportionality. The analysis results showed that the multi-axial strain in piping systems induced by seismic excitation is almost proportional. Based on this result, the authors concluded that the Rainflow cycle counting method is well applicable for the piping seismic fatigue evaluation. In addition to these numerical analyses with the IS method, some discussions are also made in this paper from the viewpoint of the relation between vibration mode and strain components to support the conclusion that the piping strain by seismic loads is proportional.
