Observation of all-in type tetrahedral displacements in nonmagnetic pyrochlore niobates

Torigoe, Shuhei*; Ishimoto, Yutaro*; Aoishi, Yuhei*; Murakawa, Hiroshi*; Matsumura, Daiju; Yoshii, Kenji; Yoneda, Yasuhiro; Nishihata, Yasuo; Kodama, Katsuaki; Tomiyasu, Keisuke*; et al.

Physical Review B, 93(8), p.085109_1 - 085109_5, 2016/02

https://doi.org/10.1103/PhysRevB.93.085109

Development of small specimen test techniques for the IFMIF test cell

Wakai, Eiichi; Kim, B. J.; Nozawa, Takashi; Kikuchi, Takayuki; Hirano, Michiko*; Kimura, Akihiko*; Kasada, Ryuta*; Yokomine, Takehiko*; Yoshida, Takahide*; Nogami, Shuhei*; et al.

Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 6 Pages, 2013/03

https://inis.iaea.org/collection/NCLCollectionStore/_Public/44/060/44060304.pdf?r=1&r=1#page=596

Small specimen test technology and methodology of IFMIF/EVEDA and the further subjects

Wakai, Eiichi; Nogami, Shuhei*; Kasada, Ryuta*; Ito, Yuzuru*; Takada, Fumiki; 6 of others*

Journal of Nuclear Materials, 417, p.1325 - 1330, 2011/10

https://doi.org/10.1016/j.jnucmat.2011.02.011

Status of Japanese design and validation activities of test facilities in IFMIF/EVEDA

Wakai, Eiichi; Kikuchi, Takayuki; Kogawara, Takafumi; Kimura, Haruyuki; Yokomine, Takehiko*; Kimura, Akihiko*; Nogami, Shuhei*; Kurishita, Hiroaki*; Saito, Masahiro*; Nishimura, Arata*; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03

Japanese activities of test facilities in IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) project have three subjects of engineering design of post irradiation examination (PIE) facilities, small specimen test technique (SSTT), and engineering design of high flux test module (HFTM), and this paper is summarized about present status. Functional analysis and design of 2-D and 3-D models of PIE facility were performed. In HFTM, as materials of heater, W-3Re alloy and/or SiC/SiC composite were selected in the points of high temperature materials, fabrication technology and some suitable properties such as resistance of thermal shock, high temperature re-crystallization, ductility, resistance of irradiation degradation, and low-activation. In SSTT, a test machine of fracture toughness was designed and developed for small specimens with 10 mm square, and it had high accuracy controllability for stress and displacement.

R&D project on irradiation damage management technology for structural materials of long-life nuclear plant; R&D of irradiation damage indicator and irradiation damage management

Wakai, Eiichi; Takada, Fumiki; Takaya, Shigeru; Kato, Shoichi; Kitazawa, Sin-iti; Okubo, Nariaki; Suzudo, Tomoaki; Fujii, Kimio; Yoshitake, Tsunemitsu; Kaji, Yoshiyuki; et al.

no journal, , 

no abstracts in English

X-ray absorption spectra and ferroelectricity in pyrochlore niobates

Nara, Shintaro*; Torigoe, Shuhei*; Hanasaki, Noriaki*; Nogami, Yoshio*; Matsumura, Daiju; Yoshii, Kenji; Yoneda, Yasuhiro; Nishihata, Yasuo

no journal, , 

We have investigated the physical properties of pyrochlore niobates YCaNbO and NdCaNbO. From synchrotron X-ray absorption and thermogravimetric measurements, the average valence of Nb ion in these oxides was determined as 4.5+, indicating the existence of charge frustration on the Nb site. These oxides have been found to show some intriguing properties such as the absence of magnetic moment of Nb, large thermoelectric effect and ferroelectricity. Possible origins of these phenomena are discussed on the basis of results of X-ray absorption measurements.

Fusion neutron effects; Estimation using ion irradiation technique

Hamaguchi, Dai; Ando, Masami; Tanigawa, Hiroyasu; Kasada, Ryuta*; Nogami, Shuhei*; Abe, Hiroaki*; Hashimoto, Naoyuki*

no journal, , 

Ion irradiation is one of a powerful method for irradiation tests because of their rapid damage production, the absence of induced radioactivity, controllable test conditions such as temperatures and doses, simultaneous introduction of damages and He gases, in order to estimate the fusion neutron irradiation effects on DEMO blanket structural materials. However, ion irradiation test is not suitable enough to acquire mechanical property degradation data since the damage layer tends to be very shallow from the surface. Despite this disadvantage, the method is still a powerful tool to understand the effects especially under high dose irradiations and also synergetic effects with He (and/or H) and damages in terms of microstructural changes. In this presentation, the recent effort on the establishment of methodologies to predict fusion neutron effects under Japanese ITER-BA activity will be reviewed, emphasizing on using the ion irradiation technique.

Effect of neutron irradiation on rhenium cluster formation in tungsten and tungsten rhenium alloys and Introduction of the research for aging management of JAEA

Hwang, T.; Hasegawa, Akira*; Tomura, Keiko*; Ebisawa, Naoki*; Toyama, Takeshi*; Nagai, Yasuyoshi*; Fukuda, Makoto*; Miyazawa, Takeshi*; Tanaka, Teruya*; Nogami, Shuhei*

no journal, , 

Effects of DPA and helium production on radiation damage microstructures etc. in irradiated austenitic stainless steels and ferritic steel

Wakai, Eiichi; Takaya, Shigeru; Nagae, Yuji; Hirade, Tetsuya; Matsui, Yoshinori; Nogami, Shuhei*; Hasegawa, Akira*; Aoto, Kazumi

no journal, , 

no abstracts in English