Atomic position and the chemical state of an active Sn dopant for Sn-doped -GaO(001)

Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*

Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03

https://doi.org/10.1063/5.0198160

Establishment of technical basis to implement accident tolerant fuels and components to existing LWRs

Yamashita, Shinichiro; Nagase, Fumihisa; Kurata, Masaki; Kaji, Yoshiyuki

Proceedings of Annual Topical Meeting on LWR Fuels with Enhanced Safety and Performance (TopFuel 2016) (USB Flash Drive), p.21 - 30, 2016/09

Fuel rod, channel box, and control rod designed with new materials and concepts have been developed in Japan for increasing accident tolerance of LWRs. In order to efficiently and properly implement the accident tolerant fuels (ATFs) and the other components, it is necessary not only to accumulate fundamental and practical data but also to consider technology readiness, recognize knowledge gaps, and establish strategy for design and fabrication. The Japan Atomic Energy Agency (JAEA) has established the above "technical basis" and drafted a research plan towards implementation of the ATFs and components as a program sponsored and organized by the Ministry of Economy, Trade and Industry (METI). It is useful to take advantage of the experiences in commercial uses of zirconium-base alloys in LWRs and, therefore, JAEA has conducted this METI project in cooperation with power plant providers, fuel venders, research institutes and universities who have been involved in the development of the ATF materials. The present paper describes the main results of the project conducted to establish the technical basis of the ATFs and components.

Role of residual transition-metal atoms in oxygen reduction reaction in cobalt phthalocyanine-based carbon cathode catalysts for polymer electrolyte fuel cell

Kobayashi, Masaki*; Niwa, Hideharu*; Harada, Yoshihisa*; Horiba, Koji*; Oshima, Masaharu*; Ofuchi, Hironori*; Terakura, Kiyoyuki*; Ikeda, Takashi; Koshigoe, Yuka*; Ozaki, Junichi*; et al.

Journal of Power Sources, 196(20), p.8346 - 8351, 2011/10

https://doi.org/10.1016/j.jpowsour.2011.06.062

The electronic structure of Co atoms in CoPc-based carbon catalysts, which were prepared by pyrolyzing a mixture of CoPc and phenol resin polymer up to 1000C, has been investigated using XAFS analysis and HXPES. The Co K XAFS spectra show that most of the Co atoms are in the metallic state and small quantities of oxidized Co components are present in the samples even after acid washing to remove Co atoms. Based on the difference in probing depth between XAFS and HXPES, it was found that after acid washing, the surface region with the aggregated Co clusters is primarily composed of metallic Co. Since the electrochemical properties remain almost unchanged even after the acid washing process, the residual metallic and oxidized Co atoms themselves will hardly contribute to the ORR activity of the CoPc-based carbon cathode catalysts, implying that the active sites of the CoPc-based catalysts primarily consist of light elements such as C and N.

X-ray photoemission spectroscopy analysis of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells

Niwa, Hideharu*; Kobayashi, Masaki*; Horiba, Koji*; Harada, Yoshihisa*; Oshima, Masaharu*; Terakura, Kiyoyuki*; Ikeda, Takashi; Koshigoe, Yuka*; Ozaki, Junichi*; Miyata, Seizo*; et al.

Journal of Power Sources, 196(3), p.1006 - 1011, 2011/02

https://doi.org/10.1016/j.jpowsour.2010.08.054

We report on the electronic structure of three different types of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells observed by hard X-ray photoemission spectroscopy. C 1s spectra show the importance of carbon network formation for the oxygen reduction reaction (ORR) activity. Samples having high oxygen reduction reaction activity in terms of oxygen reduction potential contain high concentration of graphite-like nitrogen. Based on a quantitative analysis of our results, the oxygen reduction reaction activity of the carbon-based cathode catalysts will be improved by increasing concentration of graphite-like nitrogen in a developed carbon network.

JAERI-JNC joint research report; A Study on degradation of structural materials used under the irradiation environment in nuclear reactors

Ueno, Fumiyoshi; Nagae, Yuji*; Nemoto, Yoshiyuki; Miwa, Yukio; Takaya, Shigeru*; Hoshiya, Taiji*; Tsukada, Takashi; Aoto, Kazumi*; Ishii, Toshimitsu; Omi, Masao; et al.

JAERI-Research 2005-023, 132 Pages, 2005/09

JAERI-Research-2005-023.pdf:33.03MB

JAERI and JNC have started a JAERI-JNC joint research program in fiscal year 2003, which has been aimed for efficient progress and synergistic effect on the research activities in both Institutes. This study has been chosen one of the joint research themes because it has been our common objective in the field of structural materials of FBR and LWR components. The purpose of the study is to clarify damage mechanism of structural materials used under irradiation, and then to develop the methods for damage evaluation and detection in earlier stage of progressing process of damage. In fiscal year 2004 and 2005, micro-corrosion measurement, electrochemical corrosion test and leakage magnetic flux density measurement apparatuses were developed and equipped in two hot facilities and irradiated and unirradiated crept specimens, irradiated high purity model austenitic stainless alloys were also prepared and applied to this study. These apparatuses and specimens were used for damage evaluation, and these feasibilities for nuclear power plant materials were studied.

Progress of the ITER central solenoid model coil programme

Tsuji, Hiroshi; Okuno, Kiyoshi*; Thome, R.*; Salpietro, E.*; Egorov, S. A.*; Martovetsky, N.*; Ricci, M.*; Zanino, R.*; Zahn, G.*; Martinez, A.*; et al.

Nuclear Fusion, 41(5), p.645 - 651, 2001/05

https://doi.org/10.1088/0029-5515/41/5/319

no abstracts in English

R&D for introducing advanced fuels contributing to safety improvement of current LWRs, 1; Overview of project

Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Shirasu, Noriko; Kurata, Masaki; Kaji, Yoshiyuki; Fukahori, Tokio; Watanabe, Seiichi*; Kirimura, Kazuki*; Kakiuchi, Kazuo*; et al.

no journal, , 

Since the accident at Fukushima Daiichi Nuclear Power Station, enhancing the accident tolerance of Light Water Reactors (LWRs) became a topic of serious discussion, and the research and development (R&D) for improving the safety LWRs has been activated in many countries. In Japan, the R&D project on accident tolerant fuel and other components (ATFs) of LWRs, which is sponsored and organized by the Ministry of Economy, Trade and Industry (METI), has been initiated in 2015 for establishing technical basis of ATFs. The Japan Atomic Energy Agency (JAEA) has coordinated and carried out this ATF R&D project in cooperation with power plant providers, fuel venders and universities for making the best use of the experiences, knowledges in commercial uses of zirconium-base alloys in LWRs.

Japanese R&D program for establishing technical basis of accident tolerant fuel materials

Yamashita, Shinichiro; Ioka, Ikuo; Nemoto, Yoshiyuki; Kawanishi, Tomohiro; Kaji, Yoshiyuki; Fukahori, Tokio; Nozawa, Takashi*; Watanabe, Seiichi*; Murakami, Nozomu*; Sato, Hisaki*; et al.

no journal, , 

Development of analysis method based on SAMPSON for ATF with Cr coated Zr alloy cladding

Tezuka, Kenichi*; Kino, Chiaki*; Yamashita, Susumu; Mohamad, A. B.; Nemoto, Yoshiyuki

no journal, , 

no abstracts in English

Development and implementation of accident tolerant fuel in Japan

Kaji, Yoshiyuki; Yamashita, Shinichiro; Nemoto, Yoshiyuki; Ioka, Ikuo; Osaka, Masahiko; Kawanishi, Tomohiro

no journal, , 

The JAIF International Cooperation Center will hold a local seminar in the Czech Republic as part of its efforts to promote cooperation through local seminars and invitations from Japan to countries that are promoting the expansion of nuclear power plants. In this seminar, we will introduce the current status of accident-resistant fuel development in Japan.