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Kimura, Yasuhisa; Hirano, Hiroshi; Watahiki, Masatoshi; Kuba, Meiji; Ishikawa, Shinichiro
Dekomisshoningu Giho, (52), p.45 - 54, 2015/09
The Plutonium Fuel Fabrication Facility (PFFF) of the Japan Atomic Energy Agency is now in its decommissioning phase. In the PFFF, terminated gloveboxes have been dismantled. Gloveboxes to be dismantled are surrounded by a plastic enclosure to prevent contamination from being spread into process room. Dismantling operations for gloveboxes are performed manually by workers, each wearing an air-feed suit. However, the mental and physical loads placed on workers wearing the air-feed suits are intensively high. Therefore, R&Ds on new dismantling technologies including utilization of heavy machines covered with plastic enclosure for anti-contamination have been started to reduce the potential risks associated with workers and decommissioning costs. In this paper, the status of decommissioning of the PFFF and the overview of developed dismantling technologies for 
-tight gloveboxes are described.
Kuba, Meiji; Watahiki, Masatoshi; Hirano, Hiroshi; Ishikawa, Shinichiro; Sato, Hisato
Proceedings of International Waste Management Symposia 2014 (WM2014) (Internet), 12 Pages, 2014/05
Plutonium Fuel Fabrication Facility is now in a decommissioning phase. In the facility, stabilizing activities of nuclear material residuals remained and the gloveboxes dismantling activities have been carried out simultaneously. Glovebox dismantling activities are performed manually by a worker wearing air-feed suit with mechanical tools in a plastic enclosure which is constructed around the glove boxes for preventing spread of contamination. However, the mental load and physical load of the worker are intensively high. Therefore, worker's safely issue still exists and need to be resolved. Moreover, occupational time for the worker is restricted to only one hour per day, which in turn make shortening schedule and cost savings almost impossible. R&D of new dismantling methods including application of heavy equipment with anti-contamination measure to strengthen the work performance in the plastic enclosures has been started to reduce the above mentioned potential risks and costs.
Watahiki, Masatoshi; Akai, Masanori; Nakai, Koji; Iemura, Keisuke; Yoshino, Masanori*; Hirano, Hiroshi*; Kitamura, Akihiro; Suzuki, Kazunori
Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.101 - 109, 2012/02
Gloveboxes used for plutonium fuel development and fabrication are eventually dismantled for replacement or decommissioning. Since equipment interior and the inner surface of gloveboxes are contaminated in radioactive materials, glovebox dismantling work is performed by workers wearing an air fed suit with mechanical tools in a plastic enclosure system to control the spread of contamination. Various improvements of enclosure system are implemented including modification of the rooms to decontaminate and undress the air fed suit and introduction of inflammable filter and safety film near the size reduction workspace against fire. We describe the countermeasures deployed in the enclosure system against potential hazards and how these devices work in the real dismantling activities.
Imaizumi, Tomomi; Miyauchi, Masaru; Ito, Masayasu; Watahiki, Shunsuke; Nagata, Hiroshi; Hanakawa, Hiroki; Naka, Michihiro; Kawamata, Kazuo; Yamaura, Takayuki; Ide, Hiroshi; et al.
JAEA-Technology 2011-031, 123 Pages, 2012/01
JAEA-Technology-2011-031.pdf:16.08MB
The number of research reactors in the world is decreasing because of their aging. However, the planning to introduce the nuclear power plants is increasing in Asian countries. In these Asian countries, the key issue is the human resource development for operation and management of nuclear power plants after constructed them, and also the necessity of research reactor, which is used for lifetime extension of LWRs, progress of the science and technology, expansion of industry use, human resources training and so on, is increasing. From above backgrounds, the Neutron Irradiation and Testing Reactor Center began to discuss basic concept of a multipurpose low-power research reactor for education and training, etc. This design study is expected to contribute not only to design tool improvement and human resources development in the Neutron Irradiation and Testing Reactor Center but also to maintain and upgrade the technology on research reactors in nuclear power-related companies. This report treats the activities of the working group from July 2010 to June 2011 on the multipurpose low-power research reactor in the Neutron Irradiation and Testing Reactor Center and nuclear power-related companies.
Kitamura, Akihiro; Nakai, Koji; Namekawa, Takashi; Watahiki, Masatoshi
Nuclear Engineering and Design, 241(7), p.2614 - 2623, 2011/07
Times Cited Count：5 Percentile：38.65(Nuclear Science & Technology)We developed a remote control system to display recreated three dimensional information of workspace from measured data obtained by laser rangefinder and to operate manipulator arm remotely. In order to evaluate the effectiveness and usefulness of developed system, we implemented remote handling experiments using mock up equipment and compared the performances of remote operation conducted by the present control system with that by the usual camera based control system. Impressions of operator on the performance of each system are collected and NASA TLX tests are conducted. It was observed that the present system reduced workload stresses and reinforced visual information during remote operation.
Iemura, Keisuke; Nakai, Koji; Watahiki, Masatoshi; Kitamura, Akihiro; Suzuki, Kazunori; Aoki, Yoshikazu
Dekomisshoningu Giho, (43), p.2 - 9, 2011/03
Plutonium fuel fabrication facility is constructed in 1972 and it is almost 40 years of age and equipment and components comprises the facility start degrading. Therefore we need to start dismantling gloveboxes from old ones first and at the same time to maintain the facility components and structures and gloveboxes as necessary. Also, since waste storage space is limited in the site, we effectively use open spaces generated after removing gloveboxes and equipment as temporal waste storage space. After shipping these wastes from the facility, final characterization of the facility will be conducted and demolition of the facility will be take place.
Kitamura, Akihiro; Watahiki, Masatoshi; Kashiro, Kashio
Nuclear Engineering and Design, 241(3), p.999 - 1005, 2011/03
Times Cited Count：7 Percentile：48.91(Nuclear Science & Technology)Glovebox dismantling facility is a facility to dismantle gloveboxes and recover any residual nuclear fuel material from the gloveboxes. The facility possesses one robotic arm and six master slave manipulator arms to remotely size reduce contaminated gloveboxes. In this paper the facility is described and the size reduction activity procedures are introduced. Data obtained from one of the glovebox size reduction activities, which was done by both remote and manual size reduction methods, was analyzed and a comparison of these two methods is discussed.
Tobita, Noriyuki; Okada, Takashi; Kashiro, Kashio; Matsumoto, Masaki; Watahiki, Masatoshi; Nakata, Keiji*; Gonnokami, Kiyomi*
JNC TN8430 2004-001, 125 Pages, 2004/12
JNC-TN8430-2004-001.pdf:143.53MB
An event that a pre-filter burned on fire took place in the glove box dismantlement facility of Plutonium Production Facility, on April 21, 2003. The direct cause of this event was considered to be sparks generated by an abrasive wheel cutter, some of which reached the pre-filter and eventually burned the pre-filter. Further investigation revealed that there exist other deficiencies those of which formed indirect causes of the event, such as the wheel cutter was used without protective cover and adequate shield against sparks was not installed during the operation. To prevent similar event in the future, following corrective actions were introduced. Wheel cutter will not be used without protective cover; Incombustible pre-filter will be used; Shield will be place at the front of the pre-filter. We have conducted series of experimental tests in order to evaluate and confirm the validity of these corrective actions as well as determine the cause of the fire. This report present the results of these tests.
Todokoro, Akio; Watahiki, Masatoshi; Kihara, Yoshiyuki; Ishii, Yasuhiko*; Ogasawara, Masahiro*; Otaka, Akihiro*
PNC TN8410 96-238, 86 Pages, 1996/08
None
Todokoro, Akio; Kihara, Yoshiyuki; Watahiki, Masatoshi; Ogasawara, Masahiro*; Otaka, Akihiro*
PNC TN8410 94-403, 30 Pages, 1994/11
None
Watahiki, Masatoshi; Yanagawa, Chihiro; Kageyama, Ryoichi; Kuba, Meiji
no journal, ,
We reports the examination result about the applicability of a robot arm and the applicability of a new waste container as a component engineering for glove box dismantling.
Maki, Shota; Yamashita, Kiyoto; Yokosuka, Kazuhiro; Fukui, Masahiro; Watahiki, Masatoshi
no journal, ,
Plutonium contaminated flame retardant wastes often contain chlorides it has become a key issue to establish required technologies for incinerating them, effectively. However, due to long-term operation, multiple cracks originating from the combustion air holes that supply combustion-promoting air into the furnace and the refractory inside the incinerator become more embrittled, making it difficult to continue safe operation. As a result, we set up an enclosure to prevent the spread of contamination, replaced the incinerator within it, and obtained data that can be reflected in the development of future incineration equipment.
Suzuki, Ryuta; Watanabe, Naoki; Minouchi, Hiroyuki; Maruyama, Hajime; Watahiki, Masatoshi
no journal, ,
Radioactive solid waste must be safely stored and managed for a long period of time until it is incinerated or otherwise processed at a treatment facility. To check the integrity of radioactive solid waste containers, visual inspection is periodically performed. However, since this inspection is conventionally performed by human eye, the information that can be obtained is limited. Therefore, we focused on a non-destructive inspection method using an infrared camera to detect corrosion on the inner surface of the containers that cannot be seen from the outer surface. To confirm the applicability of this new method, measurement tests using corroded mock-up containers were conducted, and the measurement results were summarized and evaluated.
