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Hirota, Takatoshi*; Nagoshi, Yasuto*; Hojo, Kiminobu*; Okada, Hiroshi*; Takahashi, Akiyuki*; Katsuyama, Jinya; Ueda, Takashi*; Ogawa, Takuya*; Yashirodai, Kenji*; Ohata, Mitsuru*; et al.
Proceedings of ASME 2021 Pressure Vessels and Piping Conference (PVP 2021) (Internet), 9 Pages, 2021/07
Ohira, Hiroaki; Doda, Norihiro; Kamide, Hideki; Iwasaki, Takashi*; Minami, Masaki*
Proceedings of 2015 International Congress on Advances in Nuclear Power Plants (ICAPP 2015) (CD-ROM), p.2585 - 2592, 2015/05
IAEA's Coordinated Research Project on Benchmark Analyses of Shutdown Heat Removal Test (SHRT) performed at the Experimental Breeder Reactor-II (EBR-II) has been carried out since 2012. The benchmark specifications were provided by the Argonne National Laboratory (ANL) and the model development for thermal-hydraulics codes and/or plant dynamics codes has been conducted by participating organizations. The experimental data were also provided by the ANL after the calculations have been performed as the blind simulation. JAEA participated in this benchmark analyses, and the plant dynamics analysis code; Super-COPD was applied to the SHRT-17 simulation. The calculated inlet temperature of the high pressure plenum agreed well with the test data in all simulation time. Although the Z-pipe inlet temperature and the IHX intermediate outlet temperature had some discrepancy in the first 400 sec. caused by larger mass flow rate of the primary pump and the perfect mixing model of upper plenum, these temperatures and the flow rate agreed well with the measured data after 400 sec. Hence it was concluded the present analytical model could predict the natural circulation in good accuracy.
Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; Morita, Toshimasa; Sasaki, Akira; Terakawa, Kota*; et al.
X-Ray Lasers 2012; Springer Proceedings in Physics, Vol.147, p.117 - 120, 2014/00
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)We have developed the femto-second laser pump and soft X-ray laser probe system in order to observe the dynamical processes of the femto-second laser ablation. By using this system, we succeed to obtain the temporal evolution of the soft X-ray reflectivity from the laser induced Pt surface. The results lead that the rate of decrease in the reflectivity of the probe beam has a non-linear relation with the pump laser fluence.
Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.
Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06
Minami, Ryutaro*; Kariya, Tsuyoshi*; Imai, Tsuyoshi*; Numakura, Tomoharu*; Endo, Yoichi*; Nakabayashi, Hidetaka*; Eguchi, Taku*; Shimozuma, Takashi*; Kubo, Shin*; Yoshimura, Yasuo*; et al.
Nuclear Fusion, 53(6), p.063003_1 - 063003_7, 2013/06
Times Cited Count：12 Percentile：47.42(Physics, Fluids & Plasmas)Ochi, Yoshihiro; Terakawa, Kota*; Hasegawa, Noboru; Yamamoto, Minoru*; Tomita, Takuro*; Kawachi, Tetsuya; Minami, Yasuo*; Nishikino, Masaharu; Imazono, Takashi; Ishino, Masahiko; et al.
Japanese Journal of Applied Physics, 51(1), p.016601_1 - 016601_3, 2012/01
Times Cited Count：10 Percentile：40.61(Physics, Applied)We have developed a soft X-ray laser interferometer based on the double Lloyd's mirror and obtained a single shot interferogram by a 7-ps pulse at the wavelength of 13.9 nm. Micrometer grooves with 5-nm depth were successfully reconstructed from the interferogram. The lateral and depth resolutions were estimated to be 1.5 
m and better than 1 nm, respectively. This interferometer will be an attractive diagnostic device for observing transiently changing nano-scale deviations on solid surfaces.
Hasegawa, Noboru; Ochi, Yoshihiro; Kawachi, Tetsuya; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; Sasaki, Akira; Terakawa, Kota*; Minami, Yasuo*; et al.
Proceedings of SPIE, Vol.8140, p.81400G_1 - 81400G_8, 2011/10
Times Cited Count：3 Percentile：82.2(Engineering, Electrical & Electronic)We have developed a soft X-ray laser (SXRL) interferometer capable of the single-shot imaging of nano-scaled structure dynamics. The interferometer consisted of the reflection optics including double Lloyd's mirrors and focusing optics, and the interference fringes are produced on the detector surface. By using this interferometer, the initial stage (
50 ps) of the ablation process of the Pt surface pumped by a 70 fs Ti:Sapphire laser pulse was observed. The expansion speed of the surface estimated from the result (34 nm/50 ps) indicated that the nano-bubble structures were formed in the initial stage of the ablation. In order to observe the detailed dynamics, the temporal synchronization between the pump and probe pulses was improved to be 3 ps by adopting a portion of the SXRL and pump beams as the time fiducials, to which the pump and probe timing was adjusted by using the X-ray streak camera.
Yamamoto, Minoru; Hasegawa, Noboru; Terakawa, Kota*; Umeda, Yoshifumi*; Tomita, Takuro*; Ochi, Yoshihiro; Nishikino, Masaharu; Ishino, Masahiko; Imazono, Takashi; Kaihori, Takeshi; et al.
Proceedings of 12th International Symposium on Laser Precision Microfabrication (LPM 2011) (Internet), 4 Pages, 2011/06
Femtosecond lasers have been used for material processing. However, the physical processes responsible for femtosecond laser ablation have not been understood completely. These processes involve melting, vaporization, re-solidification or ablation, which occur in a very short time from pico- to nano-seconds. To understand the physical processes, it is essential to reveal the dynamics of ultrafast surface morphological change after laser irradiation. At JAEA, the laser-driven plasma soft X-ray laser (SXRL) that has extremely high spatial and spectral purity was constructed. It delivers soft X-ray photons at 89.2 eV (13.9 nm) with a photon number of exceeding 
, which is sufficient to obtain a single shot interferogram. By using this system, the soft X-ray laser interferometer with the lateral resolution of 1.8 m and a depth resolution of 1 nm was developed. We report on demonstration of time-resolved measurement of femtosecond-laser ablation dynamics by using the soft X-ray laser interferometer.
Kariya, Tsuyoshi*; Minami, Ryutaro*; Imai, Tsuyoshi*; Sakamoto, Keishi; Kubo, Shin*; Shimozuma, Takashi*; Takahashi, Hiromi*; Ito, Satoshi*; Muto, Takashi*; Mitsunaka, Yoshika*; et al.
Fusion Science and Technology, 55(2T), p.91 - 94, 2009/02
Times Cited Count：11 Percentile：59.85(Nuclear Science & Technology)Isobe, Mitsutaka*; Toi, Kazuo*; Matsushita, Hiroyuki*; Goto, Kazuyuki*; Suzuki, Chihiro*; Nagaoka, Kenichi*; Nakajima, Noriyoshi*; Yamamoto, Satoshi*; Murakami, Sadayoshi*; Shimizu, Akihiro*; et al.
Nuclear Fusion, 46(10), p.S918 - S925, 2006/10
Times Cited Count：30 Percentile：69.47(Physics, Fluids & Plasmas)no abstracts in English
Hirata, Mafumi*; Miyake, Yasuhiro*; Chujo, T.*; Kohagura, Junko*; Numakura, Tomoharu*; Shimizu, Kiyoaki*; Ito, Marie*; Kiminami, Serina*; Morimoto, Naomichi*; Hirai, Katsuaki*; et al.
Review of Scientific Instruments, 77(10), p.10E719_1 - 10E719_3, 2006/10
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)no abstracts in English
Hatae, Takaki; Narihara, Kazumichi*; Yamada, Ichihiro*; Yoshida, Hidetsugu*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Minami, Takashi*; Funaba, Hisamichi*; Kajita, Shin*; Kitamura, Shigeru; et al.
no journal, ,
no abstracts in English
Hatae, Takaki; Yamada, Ichihiro*; Yoshida, Hidetsugu*; Narihara, Kazumichi*; Fujita, Hisanori*; Nakatsuka, Masahiro*; Funaba, Hisamichi*; Minami, Takashi*; Kajita, Shin*; Tojo, Hiroshi; et al.
no journal, ,
no abstracts in English
Nishikino, Masaharu; Hasegawa, Noboru; Ishino, Masahiko; Ochi, Yoshihiro; Kawachi, Tetsuya; Imazono, Takashi; Yamamoto, Minoru; Sasaki, Akira; Kaihori, Takeshi; Yamagiwa, Mitsuru; et al.
no journal, ,
no abstracts in English
Hasegawa, Noboru; Nishikino, Masaharu; Ochi, Yoshihiro; Kaihori, Takeshi; Ishino, Masahiko; Imazono, Takashi; Sasaki, Akira; Yamagiwa, Mitsuru; Kawachi, Tetsuya; Suemoto, Toru; et al.
no journal, ,
We have developed a soft X-ray laser (SXRL) interferometer capable of the single-shot imaging of nano-scaled structure dynamics. The depth and lateral resolutions of the interferometer were about 1 nm and 1.8 micron, respectively. By using this interferometer, the initial stage (50 ps) of the ablation process of the Pt surface pumped by a 70 fs Ti:Sapphire laser pulse was observed. In order to observe the detailed dynamics, the temporal synchronization between the pump and probe pulses was improved to be 3 ps by adopting a portion of the SXRL and pump beams as the time fiducials, to which the pump and probe timing was adjusted by using the X-ray streak camera.
Doda, Norihiro; Igawa, Kenichi*; Minami, Masaki*; Iwasaki, Takashi*; Ohira, Hiroaki
no journal, ,
Sodium-cooled fast reactors have been developed aiming at introducing natural circulation decay heat removal systems by utilizing the characteristic of having a large coolant temperature difference between at the inlet and at the outlet of reactor vessel. In this study, as part of validation for core hot spot evaluation method, which is required for adoption of natural circulation decay heat removal systems, EBR-II (Experimental Breeder Reactor II) shutdown heat removal test was simulated. The simulation results demonstrated that the evaluation method sufficiently predicts the whole plant thermal hydraulic behaviors and the maximum coolant temperature in a fuel subassembly in natural circulation decay heat removal.
