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Sakamoto, Naoki; Fujishima, Tadatsune; Mizukoshi, Yasutaka
Hozengaku, 19(2), p.125 - 126, 2020/07
The five post-irradiation examination facilities in JAEA's Oarai research and development institute have been operated for over 40 years in order to investigate the irradiation performance of fast reactor fuel materials. The equipment associated with these facilities has been managed to maintain secure from the problems occurred in the process of aging. Therefore, we established a safety assessment method for aging facilities in 2002, and we have been conducting maintenance management of facilities since then. In this study, improvement plans of the safety assessment method are considered in order to solve the issues detected as a result of analysis of past maintenance information.
Morooka, Satoshi
Hozengaku, 19(1), p.29 - 34, 2020/04
no abstracts in English
Suzuki, Hiroshi
Hozengaku, 19(1), p.24 - 28, 2020/04
no abstracts in English
Shimazaki, Yosuke; Yamazaki, Kazunori; Iigaki, Kazuhiko
Hozengaku, 18(1), p.16 - 20, 2019/04
no abstracts in English
Nishihara, Tetsuo; Shibata, Taiju; Inaba, Yoshitomo
Hozengaku, 18(1), p.30 - 34, 2019/04
We explain the current status of High Temperature Gas-cooled Reactor (HTGR) development in the world and international cooperation between Japan Atomic Energy Agency (JAEA) and these countries. We introduce the concept of Japanese HTGR technology deployment by using international cooperation.
Okamoto, Koji
Hozengaku, 17(4), P. 1, 2019/01
no abstracts in English
Komatsu, Kazumi*; Seki, Takeshi*; Naganawa, Akihiro*; Oka, Kiyoshi*; Nishimura, Akihiko
Hozengaku, 16(3), p.89 - 95, 2017/10
no abstracts in English
Takaya, Shigeru; Chikazawa, Yoshitaka; Hayashida, Kiichi; Tagawa, Akihiro; Kubo, Shigenobu; Yamashita, Atsushi
Hozengaku, 15(4), p.71 - 78, 2017/01
A maintenance management suitable to nuclear power plants (NPP) at R&D stage was discussed. Objectives of maintenance management of NPP at R&D stage was first clarified. Next, applicability of codes for maintenance management of commercial NPP to NPP at R&D stage was discussed. Then, requirements and consideration for maintenance management of NPP at R&D stage was proposed. Finally, an example that the proposal was applied to setting maintenance program of sodium-cooled fast reactor was presented.
Kondo, Masahiro*; Yoshimoto, Tatsuya*; Ishikawa, Jun; Okamoto, Koji*
Hozengaku, 15(4), p.79 - 85, 2017/01
no abstracts in English
Daido, Hiroyuki
Hozengaku, 15(3), p.20 - 25, 2016/10
Naraha Remote Technology Development Center is open for various users to contribute to recovery of the coast area of Fukushima as well as the decommissioning of Fukushima Daiichi Nuclear Power Station. The center is located within a distance of 20 km from the Fukushima Daiichi station. This is the first development center funded by the Government near the Fukushima Daiichi. Many people expect that the center plays a significant role to contribute to the decommissioning of Fukushima Daiichi and recovery of Fukushima area from the hazards. The author describe details of the facility and our plan.
Yada, Hiroki
Hozengaku, 15(3), P. 86, 2016/10
no abstracts in English
Takeda, Masayasu
Hozengaku, 15(2), p.31 - 34, 2016/07
no abstracts in English
Nemoto, Yoshiyuki; Oishi, Makoto; Ito, Masayasu; Kaji, Yoshiyuki; Keyakida, Satoshi*
Hozengaku, 14(4), p.83 - 90, 2016/01
Authors previously reported that magnetic data obtained by using Eddy current method and AC magnetization method showed correlation with the increase of susceptibility of the irradiation assisted stress corrosion cracking (IASCC) on neutron irradiated austenitic stainless alloy specimens. To discuss the mechanism of the correlation, microstructure observation was conducted on the irradiated specimen, and magnetic permalloy phase (FeNi) formation along grain boundary was revealed in this work. From this result, the radiation induced magnetic phase formation along grain boundary seems to be a factor of the magnetic property change of the irradiated materials, and related to the correlation between magnetic data and IASCC susceptibility. In addition, sensor probe development was conducted in this work to obtain higher sensitivity and resolution. It was applied for magnetic measurement on type304 stainless steel irradiated up to different doses. In this case, magnetic ferrite phase was existed in the type304 stainless steel sample before irradiation therefore it was concerned that magnetic measurement on the irradiated ones would be disturbed by the magnetic signal from the pre-existing ferrite phase. In the magnetic measurements, increase of the magnetic data was clearly seen on the irradiated specimens. Thus, it was thought that the developed magnetic measurement technics can be applied for the irradiated austenite stainless steels which contain certain quantity of ferrite phase before irradiation.
Takaya, Shigeru; Arakawa, Hisashi*; Keyakida, Satoshi*
Hozengaku, 14(3), p.81 - 87, 2015/10
A magnetic sensor which can be applied to measurement at elevated temperature was newly developed. It is a kind of flux gate magnetic sensor. Permendur was employed for a magnetic core instead of Permalloy which is commonly used because Permendur has much higher Curie point, about 1000C. Heat resistant ceramic coating Cu wires were used for coils. External magnetic field is detected by shift of peak position of differential permeability during induction of triangular excitation current. A magnetic core has race track shape with a fine part to make peak position more clear and increase detectability. The output of the developed sensor showed good linearity with external magnetic field even at 500
C. Furthermore, the durability of the sensor was discussed, and it was shown that decrease in coil performance after some operation at elevated temperature seems to be a critical issue.
Terada, Takaya; Nishimura, Akihiko; Oka, Kiyoshi; Moriyama, Taku*; Matsuda, Hiroyasu*
Hozengaku, 13(4), p.87 - 94, 2015/01
Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki; Omori, Tsuyoshi
Hozengaku, 13(2), p.115 - 125, 2014/07
In order to develop fuels and materials for fast reactors, five hot laboratories as a facility using nuclear materials for post irradiation examination (PIE) are now in operation at the Oarai Research and Development Centre of Japan Atomic Energy Agency. More than 30 years have passed since the first hot run of these facilities was started, and it has been indispensable to maintain the principal equipment for continuous safe operation. For application to preventive maintenance and the safe operation, a new safety review method that could be applied for these facilities was developed by modification of periodic safety review tools using for Japanese commercialized power reactors. Effective repair or replacement of equipment before malfunction have been performed and the priority for preventive maintenance could be appropriately determined for stable management of hot facility operations by the developed method.
Nakai, Satoru
Hozengaku, 13(2), p.41 - 42, 2014/07
The road map to establish a fast reactor (FR) maintenance technology in the technical aspect became clear in the examination of the FR maintenance in the Japan Society of Maintenology (JSM). It is vital to acquire operation and maintenance experience of the plant to implement this road map, and to establish a fast reactor maintenance technology. On the other hand, even if components to be maintained are defined and the maintenance methods are established, improvement of the maintenance ability in the organizations and individuals, proper and reliable implementation of the maintenance are indispensable. To improve the ability for maintenance, the action of the organized education, training and technical transmission is necessary including a light water reactor. The examination of the FR maintenance technology is a good opportunity for the application of the maintenance principles established by the JSM to the FR.
Garcia Rodriguez, D.
Hozengaku, 12(4), p.45 - 47, 2014/01
In this short letter to appear in the Japanese Society of Maintenology's next issue, I present my living and working experience in Japan during the past 4 years. I came to live here for the first time in 2005, and stayed for one year as a fellow of the EU-JP Center for Industrial Cooperation Vulcanus Program, while carrying an 8 months internship at Hitachi GE Nuclear Energy. Then, after a 4 year break to obtain my PhD at the French Atomic Commission, I enrolled in JAEA as a permanent researcher in 2010.
Niizato, Tadafumi; Kitamura, Akihiro
Hozengaku, 12(3), p.9 - 14, 2013/10
This paper presents an outline of research project of JAEA on the environmental dynamics of radiocaesium released from the Fukushima Daiichi Nuclear Power Plant to the Fukushima environment.
Wakai, Takashi
Hozengaku, 12(3), p.69 - 70, 2013/10
no abstracts in English