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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.
Tamaoki, Yuichi; Omori, Tsuyoshi; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
Proceedings of 53rd Annual Meeting of Hot Laboratories and Remote Handling Working Group (HOTLAB 2016) (Internet), 6 Pages, 2016/11
Post irradiation examinations are conducted in hot laboratories in Oarai Research and Development Center of the Japan Atomic Energy Agency in order to develop fuels and materials for fast reactors. These facilities, the majority of which were constructed in the 1970s, have accumulated operating experience over a period of more than 40 years. Continuous operational safety requires the maintenance of important equipment such as electronic devices, manipulators, in-cell cranes, as well as air conditioning and ventilation systems. A method for the periodic safety review for hot laboratories based on the periodic safety review method employed for preventive maintenance at commercialized power reactors in Japan has been developed. In this paper, the status of implementation of the periodic safety review for hot laboratories using the safety review method are introduced.
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.
Mizukoshi, Yasutaka; Yasu, Tetsunori
JAEA-Technology 2012-013, 26 Pages, 2012/06
JAEA-Technology-2012-013.pdf:6.74MB
The Materials Monitoring Facility is equipped with an exhaust stack to emit air from a controlled area (the hot laboratory) into the atmosphere. Cracks and exfoliation have been observed for the surface of the exhaust stack, which is made of reinforced concrete and was constructed on the seacoast about 25 years ago, so exposed to a salt-corrosive condition. In order to get details of the present condition of the exhaust stack, an inspection was carried out using an electromagnetic wave radar method and chloride content method. Cracks and exfoliation were observed for the whole stack surface, especially for high positions. Moreover, salt damage was observed for the outer surface of the exhaust stack, and it was estimated that the infiltration of the chloride content was about 17 mm. Based on this detailed inspection of the exhaust stack, maintenance and repair work were carried out.
Mizukoshi, Yasutaka; Kushida, Naoya
Proceedings of 47th Annual Meeting of the Working Group "Hot Laboratories and Remote Handling" (HOTLAB 2010) (CD-ROM), 4 Pages, 2010/09
On alpha tight hot cell under ventilating that has containment capability of nuclear materials, a safe and efficient maintenance method of exhaust valves which controlled negative pressure in hot cell was established at Fuels Monitoring Facility. The hot cell which required the exhaust valve maintenance needed to stop the ventilating during maintenance work because the valves could not be removed from operating exhaust system. And it was made known from prior work evaluation that this method involved long-term work, much costs and radiation waste, and large work risk. Therefore, a new method of valve maintenance under ventilating was needed due to the reductions of work period, costs and work risk.
Mizukoshi, Yasutaka; Kushida, Naoya
JAEA-Technology 2010-011, 16 Pages, 2010/06
JAEA-Technology-2010-011.pdf:1.21MB
The inside of Metallography cell, which is an alpha-tight hot cell of post irradiation examination facility, is contaminated by radioactive matters and nuclear fuel materials at high levels, because many fuel pins that were irradiated in nuclear reactor were examined in this hot cell over many years. Therefore, for reasons of safety of workers and of the requirements of the act, the devices for negative pressure controlling (e.g. automatic control exhaust valves) must be updated under the condition of maintained negative pressure in hot cell or under the condition of completion of decontamination of radioactive matters in hot cell. Update method of automatic control exhaust valves of Metallography cell at the design-time of this hot cell was that the automatic control exhaust valves were updated under the condition of no ventilation operation after completion of decontamination. However, this method harmed the experiments of fuel pins because the working period of this method needed over one year. Therefore, a safe and efficient update method of deteriorated automatic control exhaust valves that have been perennially used for control of negative pressure in Metallography cell is invented, and this method was carried out.
Fujishima, Tadatsune; Sakamoto, Naoki; Mizukoshi, Yasutaka; Amagai, Tomio; Omori, Tsuyoshi
Nihon Hozen Gakkai Dai-5-Kai Gakujutsu Koenkai Yoshishu, p.388 - 392, 2008/07
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Mizukoshi, Yasutaka; Fujishima, Tadatsune; Sakamoto, Naoki; Amagai, Tomio; Omori, Tsuyoshi
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Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki; Amagai, Tomio; Omori, Tsuyoshi
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Fujishima, Tadatsune; Amagai, Tomio; Mizukoshi, Yasutaka; Sakamoto, Naoki; Omori, Tsuyoshi
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Amagai, Tomio; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki; Omori, Tsuyoshi
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In the site of O-arai research and development center of Japan Atomic Energy Agency (JAEA), five hot laboratories for post-irradiation examination and development of plutonium fuels are operated more than 30 years. A safety review method for preventive maintenance on these hot laboratories includes test facilities and devices are established in 2003. After that, the safety review of these facilities and devices are done and taken the necessary maintenance based on the results in each year. In 2008, 372 test facilities and devices in these hot laboratories were checked and reviewed by this method. As a results of the safety review, repair issues of 38 facilities of above 372 facilities were resolved. This report shows the review results and maintenance experiences based on the results.
-tight hot cell under ventilating conditionMizukoshi, Yasutaka; Kushida, Naoya
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Fujishima, Tadatsune; Sakamoto, Naoki; Mizukoshi, Yasutaka; Amagai, Tomio; Omori, Tsuyoshi
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Isozaki, Ryosuke; Mizukoshi, Yasutaka; Katsuyama, Kozo; Kodaka, Hideo
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Sakamoto, Naoki; Fujishima, Tadatsune; Mizukoshi, Yasutaka
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Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
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Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Yonezawa, Ryoma; Suzuki, Hisashi; Mizukoshi, Yasutaka; Sakamoto, Naoki
no journal, ,
The five post-irradiation examination facilities in the Oarai Research and Development Institute of the Japan Atomic Energy Agency have been operated for over 40 years in order to investigate the irradiation performance and physicochemical characteristics of nuclear fuels and materials for fast reactors. The equipments associated with these facilities have been managed to maintain secure from the problems that 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, designing risk assessment flow is considered in order to solve the issues detected as a result of analysis based on the experience of the repairment during the periodic safety review monitoring.
Suzuki, Ryuta; Mizukoshi, Yasutaka
no journal, ,
no abstracts in English
Isozaki, Ryosuke; Tamaoki, Yuichi; Suzuki, Ryuta; Akada, Masataka; Sawahata, Satoshi; Suzuki, Hisashi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
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no abstracts in English
Sawahata, Satoshi; Tamaoki, Yuichi; Isozaki, Ryosuke; Suzuki, Ryuta; Akada, Masataka; Suzuki, Hisashi; Yonezawa, Ryoma; Fujishima, Tadatsune; Mizukoshi, Yasutaka; Sakamoto, Naoki
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