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Toyota, Kodai; Hashidate, Ryuta; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru
Hozengaku, 20(2), p.95 - 103, 2021/07
Hashidate, Ryuta; Toyota, Kodai; Takahashi, Keita; Yada, Hiroki; Takaya, Shigeru
Hozengaku, 19(4), p.115 - 122, 2021/01
In order to improve both safety and economic efficiency of a nuclear power plant, it is necessary to realize rational maintenance based on characteristics of the plant. The prototype fast-breeder reactor in Japan, Monju, spent most of the year for the maintenance. Thus, it is important to identify causes of the prolonged maintenance of Monju and to investigate countermeasures for implementation of rational maintenance of next-generation fast reactors. In this study, the authors investigated the causes of the prolonged maintenance of Monju during reactor cold shutdown based on the plant schedule of Monju. In addition, we proposed the maintenance optimization idea for next-generation fast reactors to solve the revealed issues.
Chikazawa, Yoshitaka; Takaya, Shigeru; Tagawa, Akihiro; Kubo, Shigenobu
Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 6 Pages, 2019/05
A maintenance management required to prototype nuclear power reactors has been developed. One of important mission of a prototype reactor is to develop maintenance program for commercial reactors step by step securing safety. Since operating experience at the early stage is limited, the maintenance program for the prototype reactor should be a progressive one. It has to be modified and improved frequently taking into account R&D insight and operation experiences. Additionally, the maintenance program has to consider features of the prototype reactor even at the early stage. To select maintenance grades on particular components/systems, risk informed and graded approaches are effective. And maintenance programs have to take into account degradation mechanism originally due to reactor features. In this paper, applications for maintenance program on sodium valves of prototype fast breeder reactor Monju are studied as an example of prototype sodium-cooled reactors (SFR).
Shimazaki, Yosuke; Yamazaki, Kazunori; Iigaki, Kazuhiko
Hozengaku, 18(1), p.16 - 20, 2019/04
no abstracts in English
Tamai, Hiroshi; Okubo, Ayako; Kimura, Yoshiki; Shinohara, Nobuo; Tazaki, Makiko; Shimizu, Ryo; Suda, Kazunori; Tomikawa, Hirofumi
Proceedings of INMM 58th Annual Meeting (Internet), 6 Pages, 2017/07
Nuclear forensics is a technical measure to analyse and collate samples of illegally used nuclear materials, etc., to clarify their origins, routes, etc. and contribute to criminal identifications. Close collaboration with police and judicial organizations is essential. The national response framework is being built up with international cooperation. Discussions on promoting technical capability and regional cooperation are presented.
Daido, Hiroyuki
Reza Kenkyu, 45(7), p.397 - 398, 2017/07
In this special issue, we present laser techniques applied to maintenance and repair of the social infrastructure such as tunnels, electric power generation and transportation, nuclear facilities. Remote sensing, LIBS, LIDAR, remote technologies coupled with lasers and surface cleaning are reviewed in this issue.
Kotake, Shoji*; Chikazawa, Yoshitaka; Takaya, Shigeru; Otaka, Masahiko; Kubo, Shigenobu; Arai, Masanobu; Kunogi, Kosuke; Ito, Takaya*; Yamaguchi, Akira*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
A maintenance management required to prototype nuclear power reactors is proposed. Monitoring and control of sodium impurity and thermal transient are extremely important for sodium boundary maintenance for sodium-cooled fast reactors. At the fast stage of the prototype reactor Monju operation, degradation mechanism on the piping should be demonstrated based on operation experiences. Therefore inspection on a representative position for crack indication and pipe thickness is proposed. Due to less experience of SFR plants, early detection of boundary failure is considered. For a matured operation stage, when degradation mechanism is well demonstrated based on inspection data, inspection cycle could be extended. And for commercial reactors, maintenance without inspection will be established based on accumulated operation experiences including those of the prototype reactor Monju.
Arai, Masanobu; Kunogi, Kosuke; Aizawa, Kosuke; Chikazawa, Yoshitaka; Takaya, Shigeru; Kubo, Shigenobu; Kotake, Shoji*; Ito, Takaya*; Yamaguchi, Akira*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
Applications for maintenance program on piping support of prototype fast breeder reactor Monju are studied. Based on degradation mechanism, snubbers in Monju primary cooling system showed lifetime more than the plant lifetime of 30 years by experiments conservatively. For the first step during construction, visual inspection on accessible all supports could be available. In that visual inspection, mounting conditions and damages of all accessible supports could be monitored. One of major features of the Monju primary piping system is large thermal expansion due to large temperature difference between maintenance and operation conditions. Thanks to that large thermal expansion, integrity of the piping support could be monitored by measuring piping displacement. When technologies of piping displacement monitoring are matured in Monju, visual inspection on piping support could be shifted to piping displacement monitoring. At that stage, the visual inspection could be limited only on representative supports.
Nishimura, Akihiko; Takenaka, Yusuke*
Sumato Purosesu Gakkai-Shi, 6(2), p.74 - 79, 2017/03
no abstracts in English
Tamai, Hiroshi; Okubo, Ayako; Kimura, Yoshiki; Kokaji, Lisa; Shinohara, Nobuo; Tomikawa, Hirofumi
Dai-37-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu (CD-ROM), 8 Pages, 2017/02
Nuclear Forensics capability has been developed under the international collaborations. For its effective function, technical development in analysis of seized nuclear materials as well as the institutional development in comprehensive response framework are required under individual national responsibility. In order to keep the "chain of custody" in the proper operation of sample collection at the event scene, radiological analysis at the laboratory, storage of the samples, and further inspection and trial, close cooperation and information sharing between relevant organisations are essential. IAEA issues the Implementing Guide to provide the model action plan and assists individual national development. International cooperation for the technical improvement and awareness cultivation is promoted. Examples in such national developments will be introduced and prospective technical/institutional prerequisite for nuclear forensics response framework will be studied.
Nishimura, Akihiko; Terada, Takaya; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07
Since 2007, JAEA has been developing laser based technologies of structural health monitoring. The FBG sensor made by femtosecond laser processing will be the best candidate. To make the best use of the heat resistant characteristic, the FBG sensor was embedded in metal mold by laser cladding. A groove was processed to the surface of a SUS metal plate. We used a QCW laser to weld a filler wire on the plate. A series of weld beads perfectly formed a sealing clad on the groove. Though the FBG sensor was buried tightly, no degradation on the reflection spectrum was detected after the processing. The FBG sensor could detect the vibration of the plate caused by impact shocks and audio vibration. The reflection peak of the FBG sensor under laser cladding condition was shifted to be 6 nm. We demonstrated that the corresponded temperature derive from the reflection peak shift reached 600 degrees in heat shock experiments. The installation procedure of a FBG sensor using a portable laser cladding machine was described.
Takano, Shoji*; Totsuka, Toshiyuki; Yonekawa, Izuru
KEK Proceedings 2003-16 (CD-ROM), 4 Pages, 2004/02
no abstracts in English
Sudo, Yukio
Hoshasen To Sangyo, (100), p.10 - 11, 2003/12
no abstracts in English
Matsunaga, Takeshi
JAERI-Review 2002-021, 101 Pages, 2002/10
JAERI-Review-2002-021.pdf:6.16MB
Concerning the study subject on the transport of radioactive and trace elements in a river watershed, its aims and methodological approaches have been discussed. It is stressed that a numerical model is prerequisite and to be keenly developed to assess the physiological impact and to provide appropriate countermeasures in case of a nuclear accident. The outcome of the modeling will be also important for the other environmental issues,for example, associated with metals and metalloids. From a methodological aspect, techniques, which are ought to the nuclear sciences, will have further contribution to the questions of toxic chemicals hereafter.
Onuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Samadfam, M.; Sakai, Takuro; Kamiya, Tomihiro; Sato, Takahiro*; Oikawa, Masakazu*
Nuclear Instruments and Methods in Physics Research B, 190(1-4), p.477 - 481, 2002/09
Times Cited Count：7 Percentile：44.35(Instruments & Instrumentation)Concentrations of As, Fe, Si and S contained in the biomat formed in surface-water at arsenic mine have been measured at TIARA facility of JAERI. It is obtained that As and Fe are accumulated in the biomat.
Kume, Tamikazu
Genshiryoku eye, 48(6), P. 20, 2002/06
no abstracts in English
; Maki, Akira; ; ; ; ; Fukuda, Kazuhito
JNC TN8410 2001-023, 188 Pages, 2001/11
JNC-TN8410-2001-023.pdf:30.98MB
"The 4th technological meeting of Tokai Reprocessing Plant (TRP)" was held in JNFL Rokkasyo site on octorber 11
, 2001. The report contains the proceedings, transparancies and questionnaires of themeetin. This time, we reported about "Maintenance and repair results of Tokai Reprocessing Plant" based on technology and knowledge accumulated in Tokai Reprocessing Plant.
*
JNC TN1400 2001-010, 254 Pages, 2001/07
JNC-TN1400-2001-010.pdf:14.7MB
no abstracts in English
Yoshikawa, Hideki; Ishikawa, Hirohisa;
JNC TN8200 2001-004, 160 Pages, 2001/06
JNC-TN8200-2001-004.pdf:129.13MB
None
Kato, Tomoko; Fujishima, Atsushi; Ueno, Kenichi; ; Notoya, Shin; Sonobe, Hitoshi
JNC TN8450 2001-003, 205 Pages, 2001/01
JNC-TN8450-2001-003.pdf:77.1MB
We have compiled and refined the information materials to explain ENTRY (Engineering Scale Test and Research Facility) and QUALITY (Quantitative Assessment Radionuclide Migration Experimental Facility). These include information materials to show activities for research and development of radioactive waste disposal in Tokai Works such as panels of experimental equipments. This work was carried out by a working group in Waste Isolation Research Division, Waste Management and Fuel Cycle Research Center; Tokai Works in 1998
2000. We have developed database for above information materials including typical experimental equipments of ENTRY and QUALITY. In the future, it can be easily refind in case of reconstruction of the experimental equipments. This report presents the database including the experimental equipments and several pamphlet.
