Comprehensive analysis and evaluation of Fukushima Daiichi Nuclear Power Station Unit 3

Yamashita, Takuya; Honda, Takeshi*; Mizokami, Masato*; Nozaki, Kenichiro*; Suzuki, Hiroyuki*; Pellegrini, M.*; Sakai, Takeshi*; Sato, Ikken; Mizokami, Shinya*

Nuclear Technology, 209(6), p.902 - 927, 2023/06

https://doi.org/10.1080/00295450.2022.2157663

Radiation exposure and oxidative stress status of wild Japanese macaques in the ex-evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident

Ishikawa, Ryoya*; Suzuki, Masatoshi*; Kino, Yasushi*; Endo, Satoru*; Nakajima, Hiroo*; Oka, Toshitaka; Takahashi, Atsushi*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Shinoda, Hisashi*; et al.

KEK Proceedings 2022-2, p.61 - 66, 2022/11

The balance between oxidative stress and antioxidant activity, which is a defense mechanism against oxidative stress, was investigated in the liver and bladder of wild Japanese macaques captured in Fukushima Prefecture. No significant induction of oxidative stress by exposure to environmental radionuclides after the Fukushima nuclear accident was observed, suggesting that the stress defense mechanism of the organism is activated in some organs.

Mass production of NbSn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4801904_1 - 4801904_4, 2012/06

https://doi.org/10.1109/TASC.2011.2178053

Japan Atomic Energy Agency is the first to start the mass production of the TF conductors in Phase IV in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The conductor is cable-in-conduit conductor with a central spiral. A total of 900 NbSn strands and 522 copper strands are cabled around the central spiral and then wrapped with stainless steel tape whose thickness is 0.1 mm. Approximately 60 tons of NbSn strands were manufactured by the two suppliers in December 2010. This amount corresponds to approximately 55% of the total contribution from Japan. Approximately 30% of the total contribution from Japan was completed as of February 2011. JAEA is manufacturing one conductor per month under a contract with two Japanese companies for strands, one company for cabling and one company for jacketing. This paper summarizes the technical developments including a high-level quality assurance. This progress is a significant step in the construction of the ITER machine.

Synchrotron radiation study on structure of atmospheric corrosion products formed on steel surfaces

Konishi, Hiroyuki; Yamashita, Masato*; Mizuki, Junichiro; Uchida, Hitoshi*

Characterization of Corrosion Products on Steel Surfaces, p.199 - 222, 2006/00

no abstracts in English

Characterization of rust layer formed on Fe, Fe-Ni and Fe-Cr alloys exposed to Cl-rich environment by Cl and Fe K-edge XANES measurements

Konishi, Hiroyuki; Yamashita, Masato*; Uchida, Hitoshi*; Mizuki, Junichiro

Materials Transactions, 46(2), p.329 - 336, 2005/02

https://doi.org/10.2320/matertrans.46.329

Chloride in atmosphere considerably reduces the corrosion resistance of conventional weathering steel containing a small amount of Cr. Ni is an effective anticorrosive element for improving the corrosion resistance of steel in a Cl-rich environment. In order to clarify the structure of the protective rust layer of weathering steel, Cl and Fe K-edge X-ray absorption near edge structure (XANES) spectra of atmospheric corrosion products (rust) formed on Fe, Fe-Ni and Fe-Cr alloys exposed to Cl-rich atmosphere were measured. The Fe K-XANES measurements enable the characterization of a mixture of iron oxides such as rust. The chemical composition of the rust was determined by performing pattern fitting of the measured spectra. All the rust is composed mainly of goethite, akaganite, lepidocrocite and magnetite. Among these iron oxides, akaganite in particular is the major component in the rust. Additionally, the amount of akaganite in the rust of Fe-Ni alloy is much greater than that in rust of Fe-Cr alloy. Akaganite is generally considered to facilitate the corrosion of steel, but our results indicate that akaganite in the rust of Fe-Ni alloy is quantitatively different from that in rust of Fe-Cr alloy and does not facilitate the corrosion of steel. The shoulder peak observed in Cl K-XANES spectra reveals that the rust contains a chloride other than akaganite. The energy of the shoulder peak does not correspond to that of any well-known chlorides. In the measured spectra, there is no proof that Cl, by combining with the alloying element, inhibits the alloying element from acting in corrosion resistance. The shoulder peak appears only when the content of the alloying element is lower than a certain value. This suggests that the generation of the unidentified chloride is related to the corrosion rate of steel.

Difference between Cr and Ni K-edge XANES spectra of rust layers formed on Fe-based binary alloys exposed to Cl-rich environment

Konishi, Hiroyuki; Yamashita, Masato*; Uchida, Hitoshi*; Mizuki, Junichiro

Materials Transactions, 46(1), p.136 - 139, 2005/01

https://doi.org/10.2320/matertrans.46.136

The rust layer formed on weathering steel possesses a strong protective ability against corrosives in an atmosphere. This ability is related to the structure of the rust layer. The difference in the protective ability of a rust layer in a Cl-rich environment between conventional weathering steel containing Cr and advanced weathering steel containing Ni is believed to be caused by the differences in local structural and chemical properties between alloying elements, Cr and Ni, in the rust layer. In order to examine the effect of these alloying elements on the structure of the rust layer formed on steel in a Cl-rich environment, we have performed Cr and Ni K-edge X-ray absorption near-edge structure (XANES) measurements for the rust layer of Fe-Cr and Fe-Ni binary alloys exposed to a Cl-rich atmosphere using synchrotron radiation. The results of the Cr K-edge XANES measurements for the rust layer of Fe-Cr binary alloys show that the atomic geometry around Cr depends on the concentration of Cr. Therefore, it is expected that the local structure around Cr in the rust layer is unstable. On the other hand, from the results of the Ni K-edge XANES measurements for the rust layer of Fe-Ni binary alloys, Ni is considered to be positioned at a specific site in the crystal structure of a constituent of the rust layer, such as akaganite or magnetite. As a consequence, Ni negligibly interacts with Cl ions in the rust layer.

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

Structural analysis of corrosion product of Fe-Cr alloy film using synchrotron radiation

Yamashita, Masato*; Konishi, Hiroyuki; Takahashi, Masamitsu; Mizuki, Junichiro; Uchida, Hitoshi*

Materials Science Research International, Special Technical Publication, 1, p.398 - 401, 2001/05

A rust layer on a weathering low-alloy steel has strong protective ability for atmospheric corrosion of the steel. In order to control the rust layer on steels, it is so important to know the detailed structure of rust and relate it to the protective ability of the rust layer. Especially, the position of atoms of the alloying elements in the rust layer directly control the structure and properties of the rust layer. We tried to find the atomic arrangement of the rust layer of Fe-Cr alloy film covered with thin film of electrolyte using synchrotron radiation. Grazing incidence X-ray diffraction and Mssbauer spectra showed that the rust layer was composed of -FeOOH and ultra-fine -FeOOH. By examining EXAFS spectra, Cr coming from Fe-Cr alloy film would be present in the -FeOOH. Some of Cr would be present between Fe-0-OH octahedron as interstitial atoms, as well as substituting Fe lattice site in the octahedron.

Neutronics of neutral beam injector for ITER; Japanese proposal

Inoue, Takashi; Akiba, Masato; Araki, Masanori; Hanada, Masaya; *; Mizuno, Makoto; Okumura, Yoshikazu; Ohara, Yoshihiro; Seki, Masahiro; Tanaka, Shigeru; et al.

Fusion Engineering and Design, 18, p.369 - 376, 1991/00

https://doi.org/10.1016/0920-3796(91)90153-H

no abstracts in English

Design and research of ice-blasting equipment

Shimizu, Makoto*; Kimuro, Harumi*; Ayabe, Muneo*; Kouno, Yasumasa*; Miyahara, Shuji*; Yamashita, Saburo*; Kanazawa, Kazuo*; Hayashi, Mitsuo*; Yoshizaki, Masato*

PNC TJ118 83-05VOL1, 42 Pages, 1984/03

PNC-TJ118-83-05VOL1.pdf:1.06MB

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