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Yamashita, Susumu; Tada, Kenichi; Yoshida, Hiroyuki; Suyama, Kenya
Nihon Genshiryoku Gakkai Wabun Rombunshi, 17(3/4), p.99 - 105, 2018/12
In order to reveal melt relocation behaviors of core internals phenomenologically and to reduce the uncertainties of the melt relocation analysis in existing SA analysis codes, in JAEA, the numerical simulation code for melt relocation and accumulation behaviors based on computational fluid dynamics named JUPITER has been developed. In this paper, to consider the estimation method for fuel debris composition and its re-criticality, we performed the melt accumulating and spreading simulation to the pedestal region by JUPITER and also performed re-criticality analysis by Monte Carlo Codes for Neutron Transport Calculations based on Continuous Energy and Multi-group Methods (MVP) using detailed fuel debris composition data obtained by JUPITER. From the coupled analysis on fuel debris distribution by JUPITER and MVP, we had prospects for a detailed possibility of re-criticality of fuel debris with detailed fuel debris distribution.
Otsuka, Satoshi; Kaito, Takeji; Yano, Yasuhide; Yamashita, Shinichiro; Ogawa, Ryuichiro; Uwaba, Tomoyuki; Koyama, Shinichi; Tanaka, Kenya
Journal of Nuclear Science and Technology, 50(5), p.470 - 480, 2013/05
Times Cited Count：5 Percentile：38.34(Nuclear Science & Technology)Four experimental fuel assemblies (EFAs) containing 9Cr-ODS steel cladding fuel pins were previously irradiated in the BOR-60. One of the EFAs achieved the best data, a peak burn-up of 11.9at% and a neutron dose of 51 dpa, without any microstructure instability or any fuel pin rupture. On the other hand, in another EFA (peak burn-up, 10.5at%; peak neutron dose, 44 dpa), peculiar irradiation behaviors such as microstructure instability and fuel pin rupture occurred. The combined effects of matrix Cr heterogeneity (presence of metallic Cr inclusions) and high-temperature irradiation were concluded to be the main cause of the peculiar microstructure change of 9Cr-ODS steel cladding tubes in the BOR-60 irradiation tests. They contributed to the fuel pin rupture.
Kaito, Takeji; Otsuka, Satoshi; Yano, Yasuhide; Tanno, Takashi; Yamashita, Shinichiro; Ogawa, Ryuichiro; Tanaka, Kenya
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Safe Technologies and Sustainable Scenarios (FR-13) (USB Flash Drive), 11 Pages, 2013/03
The oxide dispersion strengthened (ODS) ferritic steel claddings developed by Japan Atomic Energy Agency were irradiated in Joyo and BOR-60 in order to confirm their irradiation performance and thus judge their applicability to high burnup and high temperature fast reactor fuels. In Joyo, material irradiation tests up to 33 dpa were carried out at in the temperature range of 693 - 1108 K. The irradiation data were obtained concerning mainly mechanical properties and of microstructure stability. In BOR-60, fuel pin irradiation tests were conducted up to burnup of 11.9 at% and neutron dose of 51 dpa. The irradiation data were obtained concerning fuel-cladding chemical interaction, dimensional stability under irradiation and so on. These results showed the superior irradiation performance of the ODS ferritic steel claddings and their application possibility as fast reactor fuels. This paper describes the evaluation of the obtained irradiation data of ODS ferritic steel claddings.
Yano, Yasuhide; Ogawa, Ryuichiro; Yamashita, Shinichiro; Otsuka, Satoshi; Kaito, Takeji; Akasaka, Naoaki; Inoue, Masaki; Yoshitake, Tsunemitsu; Tanaka, Kenya
Journal of Nuclear Materials, 419(1-3), p.305 - 309, 2011/12
Times Cited Count：20 Percentile：81.43(Materials Science, Multidisciplinary)The effects of fast neutron irradiation on ring tensile properties of oxide dispersion strengthened (ODS) steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the material irradiation rig at temperatures between 693 and 1108 K to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures. The experimental results showed that there was no significant change in tensile strengths after neutron irradiation below 923 K, but the tensile strengths at neutron irradiation above 1023 K up to 33 dpa were decreased by about 20%. On the other hand, uniform elongation after irradiation was more than 2% at all irradiation conditions. The ring tensile properties of these ODS claddings remained excellent within these irradiation conditions compared with conventional 11Cr ferritic/martensitic steel (PNC-FMS) claddings.
Otsuka, Satoshi; Kaito, Takeji; Yano, Yasuhide; Yamashita, Shinichiro; Ogawa, Ryuichiro; Uwaba, Tomoyuki; Koyama, Shinichi; Tanaka, Kenya
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 6 Pages, 2011/12
This paper describes evaluation results of in-reactor integrity of 9Cr and 12Cr-ODS steel cladding tubes and the plan for reliability improvement in homogeneous tube production. A fuel assembly in the BOR-60 irradiation test including 9Cr and 12Cr-ODS fuel pins has achieved the highest burn-up, i.e. peak burn-up of 11.9at% and peak neutron dose of 51dpa, without any fuel pin rupture and microstructure instability. In another fuel assembly containing 9Cr and 12Cr-ODS steel fuel pins whose peak burn-up was 10.5at%, one 9Cr-ODS steel fuel pin failed near the upper end of the fuel column. A peculiar microstructure change occurred in the vicinity of the ruptured area. The primary cause of this fuel pin rupture and microstructure change was shown to be the presence of metallic Cr inclusions in the 9Cr-ODS steel tube, which had passed an ultrasonic inspection test for defects. In the next stage from 2011 to 2013, the fabrication technology of full pre-alloy 9Cr-ODS steel cladding tube will be developed.
studied by photoemission and soft X-ray absorption spectroscopiesUtsumi, Yuki*; Sato, Hitoshi*; Kurihara, Hidenao*; Maso, Hiroyuki*; Hiraoka, Koichi*; Kojima, Kenichi*; Tobimatsu, Komei*; Okochi, Takuo*; Fujimori, Shinichi; Takeda, Yukiharu; et al.
Physical Review B, 84(11), p.115143_1 - 115143_7, 2011/09
Times Cited Count：11 Percentile：44.51(Materials Science, Multidisciplinary)We have studied conduction-band (CB) electronic states of a typical valence-transition compound YbInCu by means of temperature-dependent hard X-ray photoemission spectroscopy (HX-PES), soft X-ray absorption spectroscopy (XAS), and soft X-ray photoemission spectroscopy (SX-PES) of the valence band. We have described the valence transition in YbInCu in terms of the charge transfer from the CB to Yb 4
states.
Maehara, Tsunehiro*; Miyamoto, Ippei*; Kurokawa, Kenya*; Hashimoto, Yukio*; Iwamae, Atsushi; Kuramoto, Makoto*; Yamashita, Hiroshi*; Mukasa, Shinobu*; Toyota, Hiromichi*; Nomura, Shinfuku*; et al.
Plasma Chemistry and Plasma Processing, 28(4), p.467 - 482, 2008/08
Times Cited Count：54 Percentile：87.7(Engineering, Chemical)
/4H-SiC(0001) interfaceYamashita, Kenya*; Kitabatake, Makoto*; Kusumoto, Osamu*; Takahashi, Kunimasa*; Uchida, Masao*; Miyanaga, Ryoko*; Ito, Hisayoshi; Yoshikawa, Masahito
Materials Science Forum, 389-393, p.1037 - 1040, 2002/00
Times Cited Count：3 Percentile：16.1(Materials Science, Multidisciplinary)no abstracts in English
Yamashita, Shinichiro; Yano, Yasuhide; Otsuka, Satoshi; Kaito, Takeji; Akasaka, Naoaki; Inoue, Masaki; Yoshitake, Tsunemitsu; Nishinoiri, Kenji; Koyama, Shinichi; Tanaka, Kenya
no journal, ,
In this work, neutron irradiation behaviour of ODS ferritic steel cladding tubes developed for fast reactor (FR) was investigated to understand the effect of neutron irradiation on their microstructures. Chemical compositions of the ODS cladding tubes examined were Fe-0.13C-8.84Cr-1.97W-0.20Ti-0.34YO
(9Cr-ODS) and Fe-0.04C-11.34Cr-1.89W-0.25Ti-0.23YO (12Cr-ODS). These ODS cladding tubes were irradiated, without fuel condition, at 731-1089 K to fast fluences ranging from 3.2 to 6.6
10
n/m
(E 
0.1 MeV) in the experimental fast reactor JOYO. Microstructural stability of these cladding tubes was evaluated using transmission electron microscope (TEM). Density of the tube specimens before and after irradiation was measured by a conventional immersion method with water, indicating that no significant swelling occurred for all the irradiated specimens. TEM observations show that the radiation-induced defect cluster formation during neutron irradiation was suppressed. It was highly possible due to high density defect sink site such as initially-existed dislocation introduced during tube fabrication process, interface between precipitates including oxide and each matrix. In addition, it revealed that oxide particles, which are closely related with high temperature strength under the practical reactor operation, were stable up to the maximum doses of this irradiation test from the analyses of TEM micrographs.
Yano, Yasuhide; Kaito, Takeji; Otsuka, Satoshi; Yamashita, Shinichiro; Inoue, Masaki; Tanaka, Kenya; Povstyanko, A. V.*
no journal, ,
no abstracts in English
Yano, Yasuhide; Yamashita, Shinichiro; Otsuka, Satoshi; Kaito, Takeji; Koyama, Shinichi; Tanaka, Kenya
no journal, ,
no abstracts in English
Sakaki, Hironao; Nishiuchi, Mamiko; Maeda, Shota; Ishida, Akihiro*; Yamashita, Tomohiro*; Katahira, Kei*; Pikuz, T.; Faenov, A.*; Esirkepov, T. Z.; Pirozhkov, A. S.; et al.
no journal, ,
We will tell about the measurement methods of the electron temperature from the laser-driven acceleration.
Yamashita, Susumu; Tada, Kenichi; Yoshida, Hiroyuki; Suyama, Kenya
no journal, ,
no abstracts in English
