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Fujiwara, Hidenori*; Nakatani, Yasuhiro*; Aratani, Hidekazu*; Kanai, Yuina*; Yamagami, Kohei*; Hamamoto, Satoru*; Kiss, Takayuki*; Yamasaki, Atsushi*; Higashiya, Atsushi*; Imada, Shin*; et al.
Physical Review B, 108(16), p.165121_1 - 165121_10, 2023/10
Lu, K.; Takamizawa, Hisashi; Li, Y.; Masaki, Koichi*; Takagoshi, Daiki*; Nagai, Masaki*; Nannichi, Takashi*; Murakami, Kenta*; Kanto, Yasuhiro*; Yashirodai, Kenji*; et al.
Mechanical Engineering Journal (Internet), 10(4), p.22-00484_1 - 22-00484_13, 2023/08
Li, Y.; Katsumata, Genshichiro*; Masaki, Koichi; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Journal of Pressure Vessel Technology, 143(4), p.041501_1 - 041501_8, 2021/08
Times Cited Count:2 Percentile:21.67(Engineering, Mechanical)Hirota, Noriaki; Takeda, Kiyoko*; Tachibana, Yukio; Masaki, Yasuhiro*
Zairyo To Kankyo, 70(3), p.68 - 76, 2021/03
Corrosion resistance of stainless steels and Ni-based alloys were evaluated in a sulfuric acid decomposition gas at high temperature. The evaluation were carried out in an environment simulated in the sulfuric acid decomposition reaction vessel for thermochemical hydrogen production process (IS process). Their corrosion films were also analyzed for better understanding of the corrosion behavior. As a result, after 100 hour corrosion test, Ni-based alloy containing 2.4% Si showed good corrosion resistance. Ferritic stainless steel containing 3% Al (3Al-Ferrite) showed better corrosion resistance. Its corrosion rate was lower than that of SiC (0.1mm/year), which is a candidate material for the sulfuric acid decomposition reaction vessel. On the other hand, Ni-based alloy pre-filmed with AlO is prepared as the relative corrosion film of 3Al-Ferrite. Its corrosion rate was significantly higher than that of 3Al-Ferrite. As the result of EPMA analysis of these oxide films, Ni-based alloy containing 2.4% Si formed Si oxide film which had some cracks after the long term corrosion test. Therefore S penetrated into grain boundaries of the matrix through the oxide film. 3Al-Ferrite formed a thin and uniform AlO film, and the penetration of S into the grain boundaries was not observed. AlO pre-film of Ni-based alloy also showed S penetration in the matrix because the AlO pre-film had many small defects originally. The corrosion oxide film of 3Al-Ferrite consisted of only -AlO, while the AlO pre-film consist of -AlO and -AlO. Those results suggest that the better corrosion resistance of 3Al-Ferrite is due to the uniform formation of dense -AlO film at the early stage of the corrosion.
Aratani, Hidekazu*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Kawada, Moeki*; Kanai, Yuina*; Yamagami, Kohei*; Fujioka, Shuhei*; Hamamoto, Satoru*; Kuga, Kentaro*; Kiss, Takayuki*; et al.
Physical Review B, 98(12), p.121113_1 - 121113_6, 2018/09
Times Cited Count:4 Percentile:26.15(Materials Science, Multidisciplinary)Nakatani, Yasuhiro*; Aratani, Hidekazu*; Fujiwara, Hidenori*; Mori, Takeo*; Tsuruta, Atsushi*; Tachibana, Shoichi*; Yamaguchi, Takashi*; Kiss, Takayuki*; Yamasaki, Atsushi*; Yasui, Akira*; et al.
Physical Review B, 97(11), p.115160_1 - 115160_7, 2018/03
Times Cited Count:3 Percentile:20.97(Materials Science, Multidisciplinary)Li, Y.; Katsumata, Genshichiro*; Masaki, Koichi*; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Suzuki, Masahide*; Kanto, Yasuhiro*
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 10 Pages, 2017/07
In Japan, a PFM analysis code PASCAL (PFM Analysis of Structural Components in Aging LWR) has been developed by the Japan Atomic Energy Agency to evaluate the through-wall cracking frequencies of Japanese reactor pressure vessels (RPVs) considering neutron irradiation embrittlement and pressurized thermal shock transients. In this study, as a part of the verification activities, a working group was established in Japan, with seven organizations from industry, universities and institutes voluntarily participating as members. The source program of PASCAL was released to the members of the working group. Through one year activities, the applicability of PASCAL for structural integrity assessments of domestic RPVs was confirmed with great confidence. This paper presents the details of the verification activities of the working group including the verification plan, approaches and results.
Li, Y.; Hayashi, Shotaro*; Itabashi, Yu*; Nagai, Masaki*; Kanto, Yasuhiro*; Suzuki, Masahide*; Masaki, Koichi*
JAEA-Review 2017-005, 80 Pages, 2017/03
For the improvement of the structural integrity assessment methodology on reactor pressure vessels (RPVs), the probabilistic fracture mechanics (PFM) analysis code PASCAL has been developed and improved in JAEA based on latest knowledge. The PASCAL code evaluates the failure probabilities and frequencies of Japanese RPVs under transient events such as pressurized thermal shock considering neutron irradiation embrittlement. In order to confirm the reliability of the PASCAL as a domestic standard code and to promote the application of PFM on the domestic structural integrity assessments of RPVs, it is important to verify the probabilistic variables, functions and models incorporated in the PASCAL and summarize the verification processes and results as a document. On the basis of these backgrounds, we established a working group, composed of experts on this field besides the developers, on the verification of the PASCAL3 which is a PFM analysis module of PASCAL, and the source program of PASCAL3 was released to the members of working group. Through one year activities, the applicability of PASCAL in structural integrity assessments of domestic RPVs was confirmed with great confidence. This report summarizes the activities of the working group on the verification of PASCAL in FY2015.
Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Aratani, Hidekazu*; Mori, Takeo*; Tachibana, Shoichi*; Yamaguchi, Takashi*; Kiss, Takayuki*; Yamasaki, Atsushi*; Yasui, Akira*; Yamagami, Hiroshi*; et al.
Journal of Electron Spectroscopy and Related Phenomena, 220, p.50 - 53, 2017/01
Times Cited Count:1 Percentile:17.26(Spectroscopy)We report the soft X-ray angle-resolved photoemission study for LaNiGe to reveal the electronic structures derived from non-4 bands of the heavy fermion compound CeNiGe. The photoemission spectra recorded at the La M absorption edges clearly show the enhancement of the La 5 components in the valence band spectra. The circular dichroism of photoemission spectra reveals the band-dependent dichroic response due to the orbital symmetry.
Yamasaki, Atsushi*; Fujiwara, Hidenori*; Tachibana, Shoichi*; Iwasaki, Daisuke*; Higashino, Yuji*; Yoshimi, Chiaki*; Nakagawa, Koya*; Nakatani, Yasuhiro*; Yamagami, Kohei*; Aratani, Hidekazu*; et al.
Physical Review B, 94(11), p.115103_1 - 115103_10, 2016/11
Times Cited Count:17 Percentile:61.47(Materials Science, Multidisciplinary)In this study, we systematically investigate three-dimensional(3D) momentum-resolved electronic structures of Ruddlesden-Popper-type iridium oxides SrIrO using soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES). Our results provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO-plane structure. This transition occurs when the spin-orbit-coupled = 1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO and -dependent oscillations of photoelectron intensity in SrIrO. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole Brillouin zone and provides a panoramic view of electronic structures.