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Shamoto, Shinichi; Yasui, Yukio*; Matsuura, Masato*; Akatsu, Mitsuhiro*; Kobayashi, Yoshiaki*; Nemoto, Yuichi*; Ieda, Junichi
Physical Review Research (Internet), 2(3), p.033235_1 - 033235_6, 2020/08
Ultralow energy magnon in yttrium iron garnet crystal has been studied by inelastic neutron scattering in an energy range from 10 to 45 
eV. When a magnetic field of about 0.1 T is applied along [111], ultralow energy magnon anomaly is found at 10 K.
Tajima, Yasuhide; Ieda, Yoshiaki
Denki Hyoron, 99(2), p.46 - 61, 2014/02
no abstracts in English
Tajima, Yasuhide; Miura, Yukitoshi; Ieda, Yoshiaki
Denki Hyoron, 98(2), p.45 - 60, 2013/02
no abstracts in English
Ieda, Yoshiaki; Chikazawa, Yoshitaka; Kotake, Shoji*
ATW; International Journal for Nuclear Power, 57(3), p.163 - 168, 2012/03
Fast reactor development experiences and status in Japan are summarized. The undergoing FaCT project is pursuing commercialization of fast reactor cycle system around 2050 under cooperation of MEXT, METI, utilities, venders and JAEA. As results of the FaCT Phase I, feasibility of the key technologies for JSFR has been evaluated and the project is waiting for launching the phase II due to the Tohoku large earthquake. It is considered that the nuclear development policy might be affected by the Tohoku large Earthquake/Tsunami in Japan. Nevertheless the significance of nuclear energy will not be changed and thus we will focus on the issues learnt from Fukushima accidents and reflect into the improvement of the safety of Monju and the safety design criteria for the next generation fast reactor systems.
Ieda, Yoshiaki; Ono, Kiyoshi; Negishi, Hitoshi; Shiotani, Hiroki; Nagaoki, Yoshihiro; Namba, Takashi
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 9 Pages, 2011/12
Since 1999, Japan Atomic Energy Agency (JAEA) has promoted R&D of the Fast Breeder Reactor Cycle in order to build the practical concepts and establish the technical systems, in cooperation with related entities. In the first 5-year of the Fast Reactor Cycle System Technology Development Project (FaCT), namely the FaCT phase1 (JFY2006-2010), the evaluation of the achievement degree to the performance target fixed by the Atomic Energy Commission and the adoption judgment of the innovative technology at present were carried out with "Sodium-cooled Fast Reactor with MOX fuel, advanced aqueous reprocessing process, and simplified MOX pellet fabrication process". FaCT phase1 moved forward almost smoothly and confirmed that the project will be able to enter the next phase to demonstrate the innovative technology by the engineering scale examination. The concrete results of the FaCT phase1 and future direction are introduced in the full paper.
Ieda, Yoshiaki; Chikazawa, Yoshitaka; Kotake, Shoji*
Proceedings of Jahrestagung Kerntechnik Annual Meeting on Nuclear Technology 2011 (DVD-ROM), 11 Pages, 2011/05
Even though international SFR circumstances were against, we kept on with our R&D steadily. As results, it has shown that commercialized SFR concept, Japan Sodium-cooled Fast Reactor (JSFR) could meet the targets. And Monju has restarted in May 2010. It is planned to be recovered for an incident on the in-vessel transfer machine aiming to 40% power operation. The undergoing FaCT project is pursuing commercialization of fast reactor cycle system around 2050 under cooperation of the government, utilities, venders and JAEA. In the FaCT Phase I, the key technologies for JSFR has been evaluated and the project is waiting for launching the phase II. Nevertheless the significance of nuclear energy will not be changed. We will focus on the issues learnt from the accidents on Fukushima Daiichi NPS and reflect its experiences into the safety design criteria for the next generation Fast Reactor systems.
Sakamoto, Yoshihiko; Sakamoto, Yoshihiko; Enuma, Yasuhiro; Ando, Masato; Nishikawa, Akira; Kotake, Shoji; Ieda, Yoshiaki
Dai-14-Kai Kantaiheiyo Genshiryoku Kaigi (2004-Nen 3-Gatsu 21-Nichi
25-Nichi), 0 Pages, 2003/00
This paper describes the summary of an interim report of phase II of the Feasibility Study on Commercialized FR Cycle Systems, related to reactor systems. Promising plant concepts (sodium-, lead-bismuth-, helium-, and water-cooled fast reactor) and reactor core concepts are presented. These concepts are quantitatively evaluated from the viewpoint of the suitability to the development targets, such as economic competitiveness, efficient utilization of resources and reduction of environmental burden, with securing safety. As results, sodium cooled fast reactor is well suited to the development targets. LBE cooled fast rector would have a potential to attain the development targets. Helium gas cooled fast reactor would have the great potential for high thermal efficiency and multipurpose energy system. And water cooled fast reactor has the advantage that there are many experiences with LWR. Furthermore the crucial issues for technical feasibility are also clarified as road map of key technology development for each concept.
Negishi, Hitoshi; Sagayama, Yutaka; Sato, Kazujiro; ; Nakai, Ryodai; Ieda, Yoshiaki
Saikuru Kiko Giho, (20), 0 Pages, 2003/00
None
Negishi, Hitoshi; ; ; ; Sato, Kazujiro; Ieda, Yoshiaki
Saikuru Kiko Giho, (16), p.1 - 12, 2002/09
None
; Ieda, Yoshiaki; Konomura, Mamoru; Shimakawa, Yoshio
Kantaiheiyo Genshiryoku Kaigi, 0 Pages, 2002/00
None
Kamide, Hideki; Ieda, Yoshiaki; Kobayashi, Jun; Ninokata, Hisashi
PNC TN9410 96-076, 72 Pages, 1996/03
A benchmark exercise for multi-dimensional thermohydralinc codes was carried out related to natural convection decay heat removal in liquid metal-cooled fast breeder reactors. A total of twelve computational methods were applied to the benchmark problem which simulated mixed forced and buoyancy driven penetration flow and thermal stratification phenomena. The applicability of turbulence models and higher order schemes of convection terms, was examined, and a combined method incorporating a higher order scheme and a turbulence model was found to be highly effective among the group of finite difference methods. The importance of turbulence models was also recognized for the finite element method. Development of a turbulence model applicable to the mixed convection flow regime was also discussed.
Niwa, Hajime; Kawata, Norio; Ieda, Yoshiaki; Sato, Ikken; Ohno, Shuji; Uto, Nariaki; Miyahara, Shinya; Kondo, Satoru; Kamide, Hideki; Yamaguchi, Akira; et al.
PNC TN9410 94-154, 317 Pages, 1995/03
None
Kobayashi, Jun; Ohshima, Hiroyuki; Kamide, Hideki; Ieda, Yoshiaki
PNC TN9410 94-277, 81 Pages, 1994/09
In the case that the Direct Reactor Auxiliary Cooling System (DRACS) is adapted as a decay heat removal system of FBR, cold fluid coming from the heat exchangers immersed directly in the hot plenum may penetrate into some subassemblies under a certain natural circulation condition. This phenomenon is important from the viewpoint of the coolability of the core, because it affects the temperature distribution in the subassemblies and the natural circulation head in a primary cooling system. The objective of this study is to obtain the fundamental understanding of the penetration phenomenon with water experiments. The test section is composed of a plenum, a cooled wall and a vertical channe1, which simulate the hot plenum, the heat exchanger and lower power subassembly, respectively. The inlet temperature of water is kept constant during a run of experiments. The velocity and temperature fields in the vertical channel are measured simultaneously with two instruments: Ultrasonic velocity Profile monitor (UVP) for an axial profile of the vertical velocity components and T-type (copper-constantan) thermocouples for the temperature fields. Inlet temperature and flow rate are selected as experimental parameters. Results of the tests are follows: (1)The transient axial profiles of velocity in the vertical channel were compared with those of temperature under the condition that the penetration flow was observed. The trend of temperature profiles agreed well with that of velocity profiles. It was, therefore, considered that the depth of the penetration flow could be estimated with the temperature data as well as the velocity data. (2)The penetraion depth is determined based on buoyancy, inertia, conduction and entrainment effects. With dimensional analysis, Gr/Re
and Pr number were derived as relevant parameters for the depth of penetration flow, z: z=f(Gr/Re, Pr). In our experiments, the depth of penetration flow could be correlated with Gr/Re as ...
Niwa, Hajime; Ieda, Yoshiaki
PNC TN9410 93-297, 82 Pages, 1993/11
This is an interim report of a study on requested roles of the Safety Engineering Reactor for Accident Phenomenology (SERAPH) project which has been performed by the working group organized under the FBR safety research specialist committee. In this working group, the future requirements for SERAPH has been studied as follows: (1)Considering that the safety level of future FBRs would be much more improved from the present concept of sodium cooled mixed-oxide fueled large scale FBR, prevention and mitigation measures could be introduced or much more enhanced. Therefore currently proposed design measures have been widely reviewed and some were newly proposed, then the information was presented to the working group. An investigation was conducted by means of "questionnaire" to the working group members asking their effectiveness and technical feasibility. (2)Based on the results of the questionnaire and discussions in the working group, "risk reduction" has been selected as an index which should be pursued of through long-term safety research where SERAPH is expected to play an important role. The presented measures were analyzed and evaluated from the viewpoint of preventing and/or mitigating important phenomena in CDA (for example, recriticality) because CDA is a risk dominant event in FBRs. (3)R&D plans of each measure were drafted and needs of in-pile and reactor-scale experiments were examined including new experimental facilities. Based on this study, new R&D themes were preliminarily selected as future requirements for the SERAPH project. The final report will be presented at the end of the FY1993. This will include the results of the additional study reflecting the comments from the members of the FBR safety research specialist committee.
Muramatsu, Toshiharu; Murata, Masayuki*; Ieda, Yoshiaki; Yamaguchi, Akira; Nagata, Takashi; Sugawara, Satoru
PNC TN9410 91-318, 48 Pages, 1991/10
In-vessel thermohydraulic analysis with multi-purpose three-dimensional code AQUA as conducted for transient simulating a pump coast down and reactor scram (manual reactor trip event) to confirm efficiency of partially dip plate equipments in a large-scale fast breeder reactor. Throught the analysis using the AQUA code and the discussion based on their results, the following results have been obtained: [Sodium Surface Velocity] Maximum surface velocity is 0.33m/s in the condition of D=0.75m and W=1.905m. The velocity is the same as that or the MONJU reactor. [Thermal Stratification] Maximum axial temperature gradient 445
C/m was calculated. The gradient is nearly equal to the results in the MONJU reactor. [Main Loop Temperature Transient] Maximum temperature transients at the outlet nozzle of reactor vessel was -0.51C/s. [Circumferential Temperature Gradient] Maximum circumferential temperature gradient at the neighborhood of reactor vessel was 67C/m. The gradient is equivalent to five times of that when a partially dip plate is not adopted.
Ieda, Yoshiaki; Kamide, Hideki; Ohshima, Hiroyuki
PNC TN9410 91-186, 52 Pages, 1991/06
Scaling laws for thermal hydraulic phenomena in FBR system under naturalcirculation decay heat removal condition have been studied. One-dimensional and three-dimensional mass, momentum and energy conservatin equation have been used for derivation of scaling criteria. On the basis of the scaling criteria, requirements for experimental system used for investigation into natural circulation phenomena have been pointed out. Adequate assignment of sodium and water experiments have been also disscussed. As for as plant dynamics under the transition from forced to natural circulation is cocerned, adequate assignment of experiments are as follows: (1)Water experiments (a)Experiments for thermal-hydraulic phenomena solely in the primary system should be conducted. (b)One should lay stress on the investigation into phenomena in the plena. (c)One-twentieth model test and much larger model test should be carried out and should be compared each other. (d)Simulated fuel pins and heat transfer tubes should be made of high thermal diffusivity material and gived and received heat by working fluid under the transient condition should be simulated correctly. (2)Sodium experiments (a)Heat transport system from core to heat sink should be simulated. (b)One should lay stress on the investigation into coupling effect between primary and secondary system. (c)The similar figure model more than one-fourth scale or the exact size model only in the axial direction is available. (d)For the one-forth model, Reynolds number and Peclet number are one order smaller than those for the reality. However, other non-dimensional numbers of the model are almost equal to those of the reality.
Ochi, Yoshihiro; Hasegawa, Noboru; Kawachi, Tetsuya; Nagashima, Keisuke; Kishimoto, Maki; Tanaka, Momoko; Nishikino, Masaharu; Sukegawa, Kota; Yamatani, Hiroshi; Kunieda, Yuichi; et al.
no journal, ,
We have developed a chirped pulse amplification laser with flash lamp pumped zigzag slab Nd:glass amplifiers for pumping the TCE X-ray lasers at 0.1-Hz repetition rate at the Japan Atomic Energy Agency. The laser provided 7 J/1.6 ps main pulse and 1/8 intensity pre-pulse at 1.2 ns before the main pulse. An energy fluctuation at 0.1-Hz operation was 20% (RMS), which was comparable with our present laser using rod amplifiers. The line focus on the target surface was 20 m in the width and 0.8 cm in the length. By using this laser, gain saturated Ni-like silver laser (
= 13.9 nm) with energy output of 
1 J was obtained. The beam divergence of the Ni-like silver laser was 
mrad. Consequently, the peak spectrum brilliance was estimated to be 10
photons/s/mm
/mrad2/0.1%BW. With 0.1-Hz repetition rate, this X-ray laser can be a powerful tool for a variety of applications.
Kawachi, Tetsuya; Kishimoto, Maki; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kunieda, Yuichi; et al.
no journal, ,
Recent progress in X-ray laser research in Japan Atomic Energy Agency is reviewed. Using the nickel-like silver soft X-ray laser at the wavelength of 13.9 nm, the application experiments have been conducted in the research fields such as material science, high-density plasma diagnostics, XRL ablation, XRL imaging using single-shot holography and atomic physics. The repetition rate of the XRL beam has been improved from each 10-20 minutes to 0.1 Hz by using new driver laser system with Nd: glass zigzag slab amplifier, and we are now constructing new beam line for the pump-probe measurement of the surface phase-transition by the method of X-ray laser interferometer. In the research activity on the extension of the wavelength region of the X-ray lasers, firstly, the demonstration of novel coherent X-ray generation by "flying mirror" technique is reported. The second is theoretical investigation of the resonance photo-pumping scheme toward water-window region.
Ieda, Yoshiaki
no journal, ,
no abstracts in English
