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Fukaya, Yuji; Okita, Shoichiro; Kanda, Shun*; Goto, Masaki*; Nakajima, Kunihiro*; Sakon, Atsushi*; Sano, Tadafumi*; Hashimoto, Kengo*; Takahashi, Yoshiyuki*; Unesaki, Hironobu*
KURNS Progress Report 2021, P. 101, 2022/07
The Japan Atomic Energy Agency (JAEA) started the Research and Development (R&D) to improve nuclear prediction techniques for High Temperature Gas-cooled Reactors (HTGRs) in 2018. The objectives are to intro-duce the generalized bias factor method to avoid full mock-up experiment for the first commercial HTGR and to improve neutron instrumentation system by virtue of the particular characteristics due to a graphite moderation system. For this end, we composed B7/4"G2/8"p8EU(3)+3/8"p38EU in the B-rack of Kyoto University Critical Assembly (KUCA) in 2021.
Sakon, Atsushi*; Hashimoto, Kengo*; Sano, Tadafumi*; Nakajima, Kunihiro*; Kanda, Shun*; Goto, Masaki*; Fukaya, Yuji; Okita, Shoichiro; Fujimoto, Nozomu*; Takahashi, Yoshiyuki*
KURNS Progress Report 2021, P. 100, 2022/07
The R&D of reactor noise analysis to obtain HTGR nuclear characteristics have been performed with Kyoto University Critical Assembly (KUCA). In the last study, a neutron detector located about 55 cm away of fuel assembly measured the auto power spectral density. However, the prompt neutron decay constants obtained by this detector was different from that of other detectors. The objective of this study is experimental study of reactor noise analysis by the power spectrum method using neutron detector placed outside reactor core.
Yoshikawa, Shinji; Minami, Masaki*; Takahashi, Tadao*
Journal of Nuclear Science and Technology, 48(4), p.709 - 714, 2011/04
In design problems of large-scale systems like fast breeder reactors, inter-relations among design specifications are very important where a selected specification option is transferred to other specification selections as a premise to be taken account in engineering judgments. These inter-relations are also important in design case studies with hypothetical adoption of rejected design options for evaluation of deviation propagations among design specifications. Some of these rejected options have potential worth for future reconsideration by some circumstance changes (e.g., advanced simulations to exclude needs for mock-up tests, etc), to contribute for flexibility in system designs. In this study, a computer software is built to visualize design problem structure by representing engineering knowledge nodes on individual specification selections along with inter-relations of design specifications, to validate the knowledge representation method and to derive open problems.
Inoue, Kazuhiko*; Shibamoto, Hiroshi*; Takahashi, Kenji; Ikutama, Shinya*; Morishita, Masaki; Aoto, Kazumi; Kasahara, Naoto; Asayama, Tai; Kitamura, Seiji
Nihon Genshiryoku Gakkai-Shi, 48(5), p.333 - 338, 2006/05
no abstracts in English
Morishita, Maaki; Kitamura, Seiji; Takahashi, Kenji; Inoue, Kazuhiko*; Kato, Asao*; Fushimi, Minoru*
JNC TY9400 2005-010, 1150 Pages, 2005/07
Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimentional seismic isolation technologies, as a part of the supporting R&D activities for the feasibility studeies on commercialized fast breeder reactor cycle systems. A reserch project by JAPC under the auspices of the Ministry of Economy,Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the reserch on the structural design technology. The reserch is reported in the following orderes, (1) Development till fiscal 2004, (2) Study on the 3-dimentional base isolation system (fiscal 2005), (3) Study on the guideline of 3-dimentional base isolation system, (4) Study on the vertical isolation system for main equiptment (fiscal 2005), (5) Study on the guideline of the vertical isolation system for main equipment.
Kitamura, Seiji; Okamura, Shigeki; Takahashi, Kenji; Kamishima, Yoshio*; Somaki, Takahiro*; Morishita, Masaki
Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.209 - 216, 2005/00
A structural concept of a vertical component isolation system for fast reactors, assuming a building adopting a horizontal base isolation system, has been studied. In this concept, a reactor vessel and major primary components are suspended from a large common deck supported by vertical isolation devices consisting of large coned disk springs. We designed the isolation device, which could be achieved vertical isolation frequency of 1 Hz and damping ratio of 20 %. Full scale coned disk spring and damper performance tests were carried out to verify the validity of design equations. And a series of shaking table test using a 1/8 scale model was performed. The test results fit well the simulation analysis results, so the validity of the design methods was able to be verified. The prospect that the vertical component isolation system applied to the FBR plant could technically realize was obtained.
Takahashi, Kenji; Inoue, Kazuhiko; Kato, Asao*; Morishita, Masaki; Fujita, Takafumi*
Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.177 - 184, 2005/00
We carried out reflection seismic and multi-offset VSP surveys at JNC Shobasama-site to develop the investigation technique in the granite area, and evaluated the applicability of these geophysical methods. As the result of this study, we consider that (1) It is possible to infer the existence of the lower angle fracture zone in the granite by reflection seismic survey and (1) Multi-offset VSP supplements the result of reflection seismic survey and it is possible to infer the distribution of the fracture zone in deeper area in the granite.
Morishita, Masaki; Kitamura, Seiji; Takahashi, Kenji; Inoue, Kazuhiko; Kida, Masanori; Moro, Satoshi*; Kato, Asao*; Fushimi, Minoru*
JNC TY9400 2004-028, 921 Pages, 2004/11
Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R&D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the structural design technology. The research scope was identified as (1) Study on Developing Program, (2) Study on 3-dimentional Entire Building Base Isolation System, and (3) Study on Vertical Isolation System for Main Equipment, and the results of this year's studies are summarized as follows. (1) Study on Developing Program -Performance Requirements for 3-dimensional Isolation Devices "The behavior of a three-dimensional isolated reactor building" and "amenity under the strong wind load" were studied in order to set up performance requirements for the three-dimensional isolation system. Consequently, it was proved for the former subject that the structure of horizontal base-dimensional isolated building was applicable to 3-D isolated building and for the latter that amenity of the operator in the 3-D isolated reactor building is not affected under the strong wind. -Development Targets and Schedules for Three-dimensional Isolation Deviece In order to select the development candidate of the three dimensional isolation devices, "evaluation items and criteria" and "technical guideline on seismic three-dimensional isolation system" were studied. For the former subject, detailed requirements to the component in the reactor building were studied based on the 2002 fiscal year result and embodied.(2) Study on 3-dimentional Entire Building Base Isolation System -The 3 system concepts nominated on 2001, "Hydraulic system", "Fiber reinforced air sp
Martin, A. J.*; Umeda, Koji; Conner, C. B.*; Weller, J. N.*; Zhao, D.*; Takahashi, Masaki*
Journal of Geophysical Research; Solid Earth, 109(B10), p.B10208_1 - B10208_20, 2004/10
Times Cited Count：60 Percentile：73.16(Geochemistry & Geophysics)We achieve this using Bayesian inference in order to combine one or more sets of information (geophysical data) to a priori assumptions of volcano spatio-temporal distributions yielding modified a posteriori probabilities.
ions in the region of the 1
2
autoionizing resonanceOura, Masaki*; Yamaoka, Hitoshi*; Kawatsura, Kiyoshi*; Kimata, Junichi*; Hayaishi, T.*; Takahashi, Takehisa*; Koizumi, Tetsuo*; Sekioka, T.*; Terasawa, Michitaka*; Ito, Yo*; et al.
Physical Review A, 63(1), p.014704_1 - 014704_4, 2001/01
Times Cited Count：15 Percentile：59.77(Optics)no abstracts in English
Yokokawa, Mitsuo; *; Hagiwara, Takashi*; Isobe, Yoko*; *; *; Tani, Keiji; *
Joho Shori Gakkai Kenkyu Hokoku, 99(21), p.55 - 60, 1999/00
no abstracts in English
Kageyama, H.*; Kawatsura, Kiyoshi*; Takahashi, R.*; Arai, Shigeyoshi*; Kambara, Tadashi*; Oura, Masaki*; Papp, T.*; Kanai, Yasuyuki*; Awaya, Yoko*; Takeshita, Hidefumi; et al.
Nuclear Instruments and Methods in Physics Research B, 107(1-4), p.47 - 50, 1996/00
Times Cited Count：2 Percentile：31.89(Instruments & Instrumentation)no abstracts in English
Kitabata, Takuya*; Ueda, Shiho*; Takahashi, Hidetaka; Kanesaki, Takuno*; Iwai, Masaki*
PNC TN3410 88-011, 22 Pages, 1988/04
Long term trends in water chemistry have been appeared in the Fugen after more than two years' hydrogen water chemistry: an increase of soluble Co-60 concentration and cyclic concentration change of Cr-51 in reactor water, an increase of soluble iron concentration in condensate, and acceleration of radioactivity buildup on pipeworks in the reactor cooling system. The hydrogen addition has been carried out using hydrogen produced by a water electrolysis system on the site. Protective effect of hydrogen addition on mitigating the IGSCC susceptibility of type 304 stainless steel is maintained. Hydrogen uptake by zircaloy-2 is not accelerated with the hydrogen addition.
*; *; *
PNC TN908 84-02, 367 Pages, 1984/03
A long-term program plan was explored by the members of Reactor Safety Section(RSS), O-arai Engineering Center, Power Reactor and Nuclear Fuel Development Corporation(PNC) for the future research and development(R&D) on the safety of liquid-metal fast breeder reactors(LMFBRs). The main objeetives of this program plan are to fulfill the requirements raised during the licensing of Monju, and to support the conceptual design and licensing of a future demonstration plant. The current program plan is restricted to R&D areas on the assessmpnt of reliability or integrity of the reactor primary system, which is the ultimate goal of PNC/RSS. Key issues are extracted based on the detailed review of the current status and understanding of the individual R&D areas. They are discussed in this report with emphasizing their needs and priorities. In summary, the future R&D in PNC/RSS should be directed toward: (1)Continuation of the developlment, improvement and verification of the large safety analysis codes such as SAS and SIMMER; (2)Continuation and initiation of out-of-pile and in-pile experimental studies to verify the above computer codes; (3)Continuation of international participation in the large code developments and in-pile experiments; (4)Initiation of an experimental study on the behavior of the molten core materials which is important in assessing the thermal consequences of an accident; (5)Method development for a mechanistic post-accident heat removal analysis; and (6)Scenario development on local-fault sequences to achieve the early detection and termination of the accidents.
Takahashi, Masaki*; Martin, A.
no journal, ,
no abstracts in English
Inoue, Kazuhiko*; Shibamoto, Hiroshi*; Takahashi, Kenji*; Ikutama, Shinya*; Morishita, Masaki; Aoto, Kazumi; Kasahara, Naoto; Asayama, Tai; Kitamura, Seiji
no journal, ,
no abstracts in English
Yoshikawa, Shinji; Minami, Masaki*; Takahashi, Tadao*
no journal, ,
Aiming at profound understanding of fast breeder reactor plants, a trial software has been built to correlate various technical information items considered in the design stage of the Japanese prototype fast breeder reactor Monju, along with some decision making consequences as of plant characteristics evaluation.
Chudo, Hiroyuki; Imai, Masaki; Harii, Kazuya; Ono, Masao; Takahashi, Ryo*; Matsuo, Mamoru; Maekawa, Sadamichi; Saito, Eiji
no journal, ,
no abstracts in English
Okuda, Takahiro; Takahashi, Hideki*; Morishita, Masaki
no journal, ,
This study describes the results of a series of seismic analyses conducted to clarify how plastic deformation of a pipe and its support structures affects the seismic response of the entire piping system. The analyses conducted include; plasticity is considered for (1)the support structure only, (2)the piping only and (3)both the piping and the support structure.
Okuda, Takahiro; Takahashi, Hideki*; Morishita, Masaki
no journal, ,
This paper describes the results of a series of seismic analyses conducted to clarify how plastic deformation of a pipe and its support structures affect the seismic response of the entire piping system. The first analyses include; plasticity is considered for (1) none, (2) the piping only, (3) the support structure only and (4) both the piping and the support structure. The second analyses are parametric survey of yield load and post yield stiffness of the restoring force characteristics of support structures.
