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Journal Articles

Cause analysis of stress corrosion cracking incident due to polyvinyl chloride cable on glove box

Yamada, Yoshikazu; Shibanuma, Kimikazu

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.648 - 654, 2019/09

During a periodic inspection, multiple spot-like nuclear material contamination (maximum 21.7 Bq) was detected at the outer surface of a glove-box (GB) body used to install equipment for fabricating mixed oxide (MOX) fuel at the Japan Atomic Energy Agency. The inspection confirmed a total of 13 cracks passing through the thickness direction of the GB and a bleeding phenomenon was observed on the polyvinyl chloride (PVC) cables in the GB. These cracks were judged as stress corrosion cracking induced by the generation of chlorine gas by irradiation of PVC cables lying against the inner surface of the GB.

Journal Articles

Mechanism of flashing phenomena induced by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Yuasa, Tomohisa*; Segawa, Tomoomi; Yamada, Yoshikazu; Kato, Yoshiyuki; Ishii, Katsunori

Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07

Mixed uranium oxide and plutonium oxide powder is produced from uranyl nitrate and plutonium nitrate mixed solution by the microwave heating denitration method in the spent fuel reprocessing process. Since the microwave heating method is accompanied by a boiling phenomenon, it is necessary to fully grasp the operating conditions in order to avoid flashing and spilling in the mass production of denitrification technology for the future. In this research, it was confirmed that a potassium chloride aqueous solution as a simulant of uranyl nitrate aqueous solution with high dielectric loss cause loss of microwave at the solution surface as the dielectric loss increased with the increase of KCl concentration by experimental and electromagnetic field analysis, and revealed that the change in the heating condition affects the generation of flushing.

Journal Articles

Flushing phenomena and flow structure by microwave heating

Fujita, Shunya*; Abe, Yutaka*; Kaneko, Akiko*; Chonan, Fuminori*; Yuasa, Tomohisa*; Yamaki, Tatsunori*; Segawa, Tomoomi; Yamada, Yoshikazu

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 8 Pages, 2017/07

From the observation results, in the process of flushing, the behaviors leading to flushing were classified divided into three types. First type is that first generation bubble from heating leads to flushing. Second type is that nucleate boiling continues during heating and stop, finally single bubble generates and leads to flushing. Third type is defined that gradual evaporation occurs without bubbles. It was revealed that the total quantities of heat released by flushing are approximately equal when assuming the flushing mechanism, it can be triggered that a large amount of micro bubbles are instantaneously generated and grew.

Journal Articles

Conceptual design of engineering-scale plant applied the simplified MA-bearing fuel fabrication process

Yamada, Yoshikazu; Segawa, Tomoomi; Kato, Masato

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 8 Pages, 2017/06

Japan Atomic Energy Agency (JAEA) have proposed the transmutation of minor actinides by fast reactors as a way to contribute significantly to the reduction of the volume and the potential radiotoxicity of radioactive wastes. In order to achieve this goal, it is important to introduce a fully automated and remote operation fuel fabrication plant with shielded hot cells and manipulators. JAEA's facilities including Plutonium Fuel Production Facility (PFPF) have fabricated MOX fuel. On the basis of the operational and technical experience obtained in above facilities, the conceptual design of engineering-scale plant applied the simplified MA-bearing fuel fabrication process with shielded hot cells and manipulator was done. It will be able to fabricate high MA-bearing fuel and to perform the maintenance and repairing of each equipment with manipulators. This plant will be constructed based on this concept and development plan.

Journal Articles

Influence of the heating method on the particle characteristics of copper oxide powders synthesized from copper nitrate aqueous solutions

Segawa, Tomoomi; Fukasawa, Tomonori*; Huang, A.-N.*; Yamada, Yoshikazu; Suzuki, Masahiro; Fukui, Kunihiro*

Chemical Engineering Science, 153, p.108 - 116, 2016/10

 Times Cited Count:3 Percentile:76.66(Engineering, Chemical)

The influence of the heating method and rate on the morphology of CuO powders synthesized from Cu(NO$$_{3}$$)$$_{2}$$$$cdot$$3H$$_{2}$$O aqueous solutions by denitration was investigated. The median diameter of the obtained powder was found to decrease as the heating rate increased, independent of the heating method. The microwave heating method remarkably reduced the particle size and enhanced the irregularity and disorder of the shape and surface of the particles, which were found to be more widely distributed. In contrast, the microwave hybrid heating method yielded the most spherical particles with the smoothest surface. It was also found that this heating method sharpened the particle size distribution and had higher energy efficiency than the MW method. Numerical simulations also indicated a difference in the energy efficiency between these two methods. The simulations also revealed that the hybrid method could heat the whole reactor more uniformly with a lower microwave output.

Journal Articles

Influence of heating method on size and morphology of metallic oxide powder synthesized from metallic nitrate solution

Segawa, Tomoomi; Fukasawa, Tomonori*; Yamada, Yoshikazu; Suzuki, Masahiro; Yoshida, Hideto*; Fukui, Kunihiro*

Proceedings of Asian Pacific Confederation of Chemical Engineering 2015 (APCChE 2015), 8 Pages, 2015/09

A mixed solution of uranyl nitrate and plutonium nitrate is converted to MOX raw powder by the microwave heating de-nitration method in nuclear reprocessing. Copper oxide synthesized by heating de-nitration was used as a model for the de-nitration process. The microwave heating method (MW) and infrared heating method (IR) were used, and how they and their heating rate influence the obtained particle morphology and size were investigated. The particles obtained by the MW and IR were sufficiently similar in the surface morphology and the mass median diameter was decreased by the increased heating rate. The mass median diameters by the MW were the heating rate and smaller than those obtained by IR. The particle size distribution of the particle obtained by the MW was broader than that by the IR. The relationship of the temperature distribution and particle size distribution by the MW was discussed by the numerical simulation.

Journal Articles

The Criteria of flushing phenomena under microwave heating

Yamaki, Tatsunori*; Abe, Yutaka*; Kaneko, Akiko*; Segawa, Tomoomi; Kawaguchi, Koichi; Yamada, Yoshikazu; Fujii, Kanichi*

Journal of Nuclear Science and Technology, 52(2), p.241 - 250, 2015/02

 Times Cited Count:3 Percentile:60.55(Nuclear Science & Technology)

In the Microwave Heating de-nitration method developed in Japan, a mixed solution of uranyl nitrate and plutonium nitrate recovered from the spent fuel in the reprocessing plant is converted directly to mixed oxide (MH-MOX) powder. This MH-MOX powder is utilized to fabricate MOX fuel with UO$$_{2}$$ powder for FBR. The MH method is accompanied with transient boiling phenomena such as overflow and flushing. Toward high-speed and high-capacity conversion by MH-method in the future, it is required to avoid overflow and flushing and to understand optimal design conditions for design and operation. At the first step for these objectives, basic knowledge of transient boiling phenomena by the MH-method has been acquired with using distilled water. It was observed that generation of singular bubble triggered flushing and distilled water just before flushing was superheated by a temperature 10 degrees centigrade higher than boiling temperature. Based on these results, it is clarified that the occurrence criteria of flushing correlate with absorbed power in the water and released power from the water surface.

JAEA Reports

Study on engineering technologies in the Mizunami Underground Research Laboratory; FY2012 (Contract research)

Fukaya, Masaaki*; Noda, Masaru*; Hata, Koji*; Takeda, Yoshinori*; Akiyoshi, Kenji*; Ishizeki, Yoshikazu*; Kaneda, Tsutomu*; Sato, Shin*; Shibata, Chihoko*; Ueda, Tadashi*; et al.

JAEA-Technology 2014-019, 495 Pages, 2014/08

JAEA-Technology-2014-019.pdf:82.23MB

The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) research on engineering technology deep underground, and (2) research on engineering technology as a basis of geological disposal. The former research is mainly aimed in this study, which is categorized in (a) development of design and construction planning technologies, (b) development of construction technologies, (c) development of countermeasure technologies, and (d) development of technologies for security. In this study, the researches on engineering technology are being conducted in these four categories by using data measured during construction as a part of the second phase of the MIU plan.

Journal Articles

Prototype manufacturing of small tritium target inside JAEA

Tanaka, Shigeru; Abe, Yuichi; Kawabe, Masaru; Kutsukake, Chuzo; Oginuma, Yoshikazu; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko; Konno, Chikara

Journal of Plasma and Fusion Research SERIES, Vol.9, p.338 - 341, 2010/08

We have conducted a small tritium target production R&D for FNS inside JAEA. The tritium target is produced by adsorbing tritium in a thin titanium layer. Since titanium is very active to oxygen, glow discharge cleaning was carried out to remove an oxidation film of the titanium surface. Through many tests with deuterium, we found out that it was not an oxidation film but humidity to disturb tritium absorption. The following procedures were necessary; (1) to outgas the inside of an absorption chamber, (2) to keep environmental humidity under 3% in handling the titanium-deposited substrate, (3) to keep the titanium-deposited target substrate in the vacuum. The DT neutron generation performance of the tritium target produced with the above procedures was the same as that with discharge cleaning. The manufacture condition of the small target was established.

Journal Articles

Development of continuous sintering equipment for MOX fuel fabrication

Yamada, Yoshikazu; Kurita, Ichiro; Suzuki, Kazunori; Shinada, Kenta; Kato, Mitsuaki*

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10

None

Journal Articles

Development of a 13-T and 40-kA Nb$$_{3}$$Al conductor for toroidal coils of fusion reactors

Koizumi, Norikiyo; Ando, Toshinari; Sugimoto, Makoto; Takahashi, Yoshikazu; Tsuji, Hiroshi; Shimamoto, Susumi; Yamada, Yuichi*; *; *

Fusion Engineering and Design, 41, p.277 - 281, 1998/00

 Times Cited Count:6 Percentile:47.71

no abstracts in English

JAEA Reports

Evaluation on stregth of reinforced concrete slabs

Yamada, Toshiro*; Ishida, Masatoshi*; Sawamoto, Yoshikazu*

PNC-TJ8100 97-001, 83 Pages, 1997/11

PNC-TJ8100-97-001.pdf:1.98MB

None

Journal Articles

Experimental result of 13T-46kA Nb$$_{3}$$Al conductor in SULTAN

Nunoya, Yoshihiko; Oshikiri, Masayuki*; Ando, Toshinari; Takahashi, Yoshikazu; Nakajima, Hideo; Sugimoto, Makoto; Tsuji, Hiroshi; Shimamoto, Susumi; Yamada, Yuichi*; *

Proc. of 16th Int. Cryogenic Engineering Conf. /Int. Cryogenic Materials Conf., 0, p.1665 - 1668, 1996/00

no abstracts in English

Journal Articles

Experimental results of 40-kA Nb$$_{3}$$Al cable-in-conduit conductor for fusion machines

Takahashi, Yoshikazu; Sugimoto, Makoto; Isono, Takaaki; Nakajima, Hideo; Ando, Toshinari; Oshikiri, Masayuki*; Hosono, Fumikazu*; *; *; Hanawa, Hiromi*; et al.

IEEE Transactions on Magnetics, 30(4, Part2), p.2531 - 2534, 1994/07

no abstracts in English

Journal Articles

AC losses in a multifilamentary Nb$$_{3}$$Al/Cu composite superconductor made by a jelly roll process

Ando, Toshinari; Takahashi, Yoshikazu; Nishi, Masataka; Yamada, Yuichi*; *; *

Advances in Cryogenic Engineering, Materials, Vol.38, p.813 - 820, 1992/00

no abstracts in English

JAEA Reports

2nd power-up test for JRR-2

Kambara, Toyozo; Uno, Hidero; Shoda, Katsuhiko; Hirata, Yutaka; Shoji, Tsutomu; Kohayakawa, Toru; Takayanagi, Hiroshi; Fujimura, Tsutomu; Morita, Morito; Ichihara, Masahiro; et al.

JAERI 1045, 11 Pages, 1963/03

JAERI-1045.pdf:0.72MB

no abstracts in English

Oral presentation

The Pellet grinding and inspection equipment

Yamada, Yoshikazu; Suzuki, Yoshihiro*

no journal, , 

no abstracts in English

Oral presentation

Development of actinides co-extraction system with direct extraction process using supercritical fluid, 10; Direct extraction test of unirradiated MOX fuel under supercritical condition

Kaji, Naoya; Kamiya, Masayoshi; Koma, Yoshikazu; Koizumi, Tsutomu; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*

no journal, , 

no abstracts in English

Oral presentation

Development of simplified pelletizing process for fast reactor MOX fuels, 3; Development of die wall lubrication pressing method

Sudo, Katsuo; Okita, Takatoshi; Takeuchi, Kentaro; Takano, Tatsuo; Kato, Akebumi*; Haga, Tetsuya; Yamada, Yoshikazu; Kihara, Yoshiyuki

no journal, , 

no abstracts in English

Oral presentation

Manufacturing of large tritium target for DT neutron generation inside JAEA

Abe, Yuichi; Tanaka, Shigeru; Kawabe, Masaru*; Oginuma, Yoshikazu; Kutsukake, Chuzo; Yamada, Masayuki; Suzuki, Takumi; Yamanishi, Toshihiko; Konno, Chikara

no journal, , 

no abstracts in English

38 (Records 1-20 displayed on this page)