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Asano, Norikazu; Nishimura, Arashi; Takabe, Yugo; Araki, Daisuke; Yanai, Tomohiro; Ebisawa, Hiroyuki; Ogasawara, Yasushi; Oto, Tsutomu; Otsuka, Kaoru; Otsuka, Noriaki; et al.
JAEA-Technology 2021-045, 137 Pages, 2022/06
JAEA-Technology-2021-045.pdf:2.97MB
A collapse event of a cooling tower for secondary cooling system in the Japan Materials Testing Reactor (JMTR) was caused by the strong winds of Typhoon No.15 on September 9, 2019. As measures against the event, the working group for the renewal of the UCL (Utility Cooling Loop) cooling tower was established in the department of JMTR, and the integrity of the UCL cooling tower, which is the same type of wooden cooling tower as the secondary cooling tower in the JMTR, was investigated. As a result of this investigation, we have decided to replace the existing UCL cooling tower with a new cooling system. After investigations, in order to reduce the risk of collapse due to wood decay, the new cooling system was installed as a component of the air system to be managed as a performance maintenance facility after decommissioning. This report describes the design of and the evaluation results of the facility.
Oto, Tsutomu; Asano, Norikazu; Kawamata, Takanori; Yanai, Tomohiro; Nishimura, Arashi; Araki, Daisuke; Otsuka, Kaoru; Takabe, Yugo; Otsuka, Noriaki; Kojima, Keidai; et al.
JAEA-Review 2020-018, 66 Pages, 2020/11
JAEA-Review-2020-018.pdf:8.87MB
A collapse event of the cooling tower of secondary cooling system in the JMTR (Japan Materials Testing Reactor) was caused by the strong wind of Typhoon No.15 on September 9, 2019. The cause of the collapse of the cooling tower was investigated and analyzed. As the result, it was identified that four causes occurred in combination. Thus, the soundness of the cooling tower of Utility Cooling Loop (UCL cooling tower), which is a wooden cooling tower installed at the same period as the cooling tower of secondary cooling system, was investigated. The items of soundness survey are to grasp the operation conditions of the UCL cooling tower, to confirm the degradation of structural materials, the inspection items and inspection status of the UCL cooling tower, and to investigate the past meteorological data. As the results of soundness survey of the UCL cooling tower, the improvement of inspection items of the UCL cooling tower was carried out and the replacement and repair of the structural materials of the UCL cooling tower were planned for safe maintenance and management of this facility. And the renewal plan of new cooling tower was created to replace the existing UCL cooling tower. This report is summarized the soundness survey of the UCL cooling tower.
Kawamata, Takanori; Oto, Tsutomu; Ogasawara, Yasushi; Watahiki, Shunsuke; Araki, Daisuke
UTNL-R-0486, p.8_1 - 8_10, 2014/03
no abstracts in English
Kusunoki, Hidehiko; Oto, Tsutomu; Asano, Norikazu; Hanakawa, Hiroki
UTNL-R-0483, p.10_7_1 - 10_7_9, 2013/03
no abstracts in English
Takemoto, Noriyuki; Oto, Tsutomu; Magome, Hirokatsu; Izumo, Hironobu; Hori, Naohiko
JAEA-Technology 2012-011, 53 Pages, 2012/03
JAEA-Technology-2012-011.pdf:4.22MB
A simulator of irradiation test reactors has been developed since JFY 2010 for understanding reactor behavior and for upskilling in order to utilize for a nuclear human resource development (HRD) and to promote partnership with developing countries which have a plan to introduce nuclear power plant. The simulator is designed based on the one of the irradiation test reactors, the JMTR, and it simulates operating, irradiation tests and various kinds of accidents caused in the reactor and the irradiation facility. The development of the simulator is sponsored by the Japanese government as one of the specialized projects of advanced research infrastructure in order to promote basic as well as applied researches. The training of operation using the simulator will be started for the nuclear HRD from JFY 2012. This report summarizes the result of the conceptual design of the simulator in JFY 2010.
Oto, Tsutomu; Kimura, Tadashi; Fukasaku, Akitomi; Kusunoki, Tsuyoshi
JAEA-Review 2010-066, 22 Pages, 2011/01
JAEA-Review-2010-066.pdf:3.94MB
The refurbishment of JMTR is scheduled from the beginning of FY 2007 to the end of FY 2010. An integrity investigation for concrete structures of the JMTR buildings was carried out in early phase of the refurbishment. This paper describes investigated results and repair work of the vent stack, trenches, canal building and the filter bank. Investigated items were the concrete surface deterioration, rebound number (nondestructive estimation of strength), comprehensive strength using drilled concrete core test piece, carbonation depth, reinforced bar corrosion and chloride ion content. The integrity of these concrete structures was confirmed by these investigations. Based on the investigation results, repair works such as re-painting were carried out from the viewpoint of preventive maintenance for the vent stack, trenches and canal building.
Oto, Tsutomu; Kimura, Tadashi; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-017, 21 Pages, 2010/07
JAEA-Review-2010-017.pdf:7.68MB
An integrity investigation of a Canal Expanded Joint was carried out as one of the integrity investigation of the JMTR reactor building related facilities and components, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. The Canal Expanded Joint will be used for long-term after the JMTR restart. In the integrity investigation, the visual inspection, the performance test (Surface observations, Durometer hardness test) were investigated respectively and the integrity of the Canal Expanded Joint was confirmed. In order to use the Canal Expanded Joint continuously for long-term, it is important for maintaining the integrity of the Canal Expanded Joint by the periodical maintenance and the repairing work including that has been conducted up to now.
Miyauchi, Masaru; Kimura, Tadashi; Oto, Tsutomu; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-008, 106 Pages, 2010/06
JAEA-Review-2010-008.pdf:8.89MB
An integrity investigation was carried out for the JMTR Concrete Structure (Vent Stack, Trench, Canal Building, Filter Bank), which was the concrete structure and would be used for the long-term after JMTR restart, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. In the integrity investigation, the concrete surface deterioration, the rebound number (nondestructive strength test), compressive strength using drilled concrete core test piece, the static modules of elasticity, the carbonation depth, the reinforced bar corrosion and the chloride ion content were investigated respectively and the integrity of concrete was confirmed. After the investigation, repair works such as re-painting of the Vent Stack and Trench were carried out from the viewpoint of prevention of flaking off, floating of the painting and the thinning due to the investigation results. In order to use the JMTR concrete structure continuously for long-term, it is important for maintaining the integrity of a concrete structure by the periodical maintenance and the repairing work including the building outer-wall surface painting that has been conducted up to now.
Kimura, Tadashi; Oto, Tsutomu; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2010-001, 27 Pages, 2010/03
JAEA-Review-2010-001.pdf:18.81MB
In order to investigate an integrity of the UCL (Utility Cooling Line) elevated water tank to be used for a long term after the JMTR restart, investigation on the base of the UCL elevated tank, especially for the part which had a significant aged effect, was carried out before the refurbishment work of the JMTR related facilities which had begun in FY2007. In the integrity investigation, it was confirmed that some part of the base bolts had significant aged effects, there were no evidence of crack and false indication in the welding region though thinning were observed in some parts of the base plate and the surrounding plate. After the investigation, repair works such as re-painting of the UCL elevated water tank were carried out from the viewpoint of prevention of flaking off, floating of the painting and the thinning due to corrosion based on the investigation results. In order to maintain the integrity of the UCL elevated tank, the periodical maintenance and the repair works of the base of the UCL elevated tank are important for continuous use of it in future.
Kimura, Tadashi; Oto, Tsutomu; Miyauchi, Masaru; Nemoto, Nobuaki; Tobita, Kenji; Fukasaku, Akitomi; Takahashi, Kunihiro
JAEA-Review 2009-054, 73 Pages, 2010/03
JAEA-Review-2009-054.pdf:6.79MB
An integrity investigation was carried out for the JMTR reactor building, which was the concrete structure and would be used for the long-term after JMTR restart, before the repair or replacement work of the JMTR related facilities that had begun in FY2007. In the integrity investigation, the concrete surface deterioration, the rebound number (nondestructive strength test), compressive strength using drilled concrete core test piece, the static modules of elasticity, the carbonation depth, the reinforced bar corrosion and the chloride ion content were investigated respectively and the integrity of concrete was confirmed. In order to use the JMTR reactor building continuously for long-term, it is important for maintaining the integrity of a concrete structure by the periodical maintenance and the repairing work including the building outer-wall surface painting that has been conducted up to now.
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
JAEA-Technology-2009-030.pdf:69.18MB
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Kimura, Tadashi; Oto, Tsutomu; Izumo, Hironobu; Nagao, Yoshiharu; Kawamura, Hiroshi
JAEA-Review 2008-080, 16 Pages, 2009/03
JAEA-Review-2008-080.pdf:3.11MB
The ion exchange resin is used for the purification system of the primary cooling water and the pool canal water in the JMTR. The spent ion exchange resin is stored in the liquid waste tank. The amount of the spent ion exchange resin in the liquid waste tank increases with reactor operation. The possibility of the spent ion exchange resin processing for oversea processing facilities was examined as a procedure for processing of the spent ion exchange resin. As the results, technical, regulations, and social issues were extracted from the procedure of spent ion exchange resin processing at oversea processing facilities. Furthermore, the conditions of oversea processing were indicated.
Gorai, Shigeru; Hanawa, Yoshio; Ebisawa, Hiroyuki; Oto, Tsutomu; Fukasaku, Akitomi
UTNL-R-0466, p.1_2_1 - 1_2_8, 2008/03
no abstracts in English
Oto, Tsutomu; Ebisawa, Hiroyuki; Onoue, Ryuji; Echigoya, Shinichi; Fukasaku, Akitomi
no journal, ,
no abstracts in English
Oto, Tsutomu; Kimura, Tadashi; Fukasaku, Akitomi; Kusunoki, Tsuyoshi
no journal, ,
The refurbishment of JMTR is scheduled from the beginning of FY 2007 to the end of FY 2010. An integrity investigation for concrete structures of the JMTR buildings was carried out in early phase of the refurbishment. These concrete structures have been used for more than 40 years after completion of the construction and are expected to be used more than 20 year from restart of the JMTR. The investigated items were the concrete surface deterioration, the rebound number (nondestructive strength test), the comprehensive strength using drilled concrete core test piece, the carbonation depth, the reinforced bar corrosion and the chloride ion content. This paper describes the investigated results and repair work of the vent stack, the trenches, the canal building and the filter bank.
Oto, Tsutomu; Nemoto, Hiroyoshi; Kimura, Tadashi; Watahiki, Shunsuke; Hasegawa, Teiji; Ouchi, Takuya; Echigoya, Shinichi; Fukasaku, Akitomi
no journal, ,
no abstracts in English
Yanai, Tomohiro; Ogasawara, Yasushi; Hanakawa, Hiroki; Oto, Tsutomu; Kawamata, Takanori; Kameyama, Yasuhiko
no journal, ,
JMTR refurbishment had started since 2007. Refurbishment of instrumentation system has completed on March 2011. Official inspections before operation was carried out 4 times between March 2010 and April 2011. Refurbishment work was carried out in schedule except delay of the last inspection official inspection before operation due to Great East Japan Earthquake. Instrumentation system had used for 42 years since first criticality. Nuclear instrumentation was partly refurbished in 1981 but other instrumentation devices were in service till August 2006. The refurbishment plan was made not only by using original design concept also by considering aging, important degree of safety, availability of change parts, and raising operation rate. Almost all devices were renewal in this refurbishment work in order to be able to use the instrumentation system for 20 year for which JMTR will operate. This report summarized the refurbishment work and future task of JMTR instrumentation system.