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Ito, Hirokuni*; Hatakeyama, Mutsuo*; Tachibana, Mitsuo; Yanagihara, Satoshi
JAERI-Tech 2003-012, 34 Pages, 2003/03
The MISE was developed to evaluate low-level radiological contaminations of inner surfaces of piping. The MISE consists of a cylindrically-formed double layered type detector and a piping crawling robot, which were designed and manufactured separately. In measurements of the contaminations, an outer cylindrical detector close to the surface of piping measures -rays and -rays and an inner cylindrical detector set after a shielding plate for shield of -rays measures -rays. The -ray counting rates are derived by subtracting -ray counts measured by the inner detector from - and -ray counts measured by the outer detector. The robot transports the double layered type detector with observing inner surfaces of piping. The detection limit for the contamination of Co was found to be about 0.17Bq/cm with measurement time of 30 seconds. It is expected that 0.2Bq/cm corresponding to clearance level of Co (0.4Bq/g) can be evaluated with measurement time of 2 seconds, which is equal to measurement speed of 54m/h.
Tachibana, Mitsuo; Shimada, Taro; Yanagihara, Satoshi
Nihon Kikai Gakkai Dai-8-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.489 - 492, 2002/06
A remote dismantling robot was developed for decommissioning in nuclear facilities. The remote dismantling robot consists of two electrical powered manipulators, end-effectors and a control system. To realize stable dismantling operation remotely, the remote dismantling robot is designed from view point of proper control in coping with different activity conditioning by feedback of image and of force to the control system. The image feedback was considered to obtain accurate positioning of the end-effectors and the force feedback was considered to supply proper force for direct interaction with an object. Motion tests were performed to verify the remote dismantling robot and its control system. As a result, it was confirmed that the remote dismantling activities such as cutting, radioactivity measurement, decontamination were conducted efficiently by using the image feedback and the force feedback.
Shimada, Taro; Tachibana, Mitsuo; Yanagihara, Satoshi
JAERI-Tech 2001-060, 44 Pages, 2001/09
To evaluate aerosol diffusion behaviors under dismantling of nuclear facilities, plasma arc cuttings were conducted in the enclosure. The flow of air and high temperature gas in the enclosure were visualized, and the temperature distributions in the enclosure and the aerosol number and weight density in air of outlet flow were measured in the experiments. As a result, it was confirmed that ascending high temperature gas flow produced by the plasma arc is corresponded with aerosol diffusion behavior during cutting. It was also confirmed that after completing the cuttings the aerosol tends to fall due to decreasing of flow velocity of high temperature gas and the aerosol which reaches near the floor is resuspended by relatively high velocity exhaust flow.
Sukegawa, Takenori; Hatakeyama, Mutsuo; Yanagihara, Satoshi
JAERI-Tech 2001-058, 81 Pages, 2001/09
In general, neutron transport and activation calculation codes are used for residual radioactive inventory estimation; however, it is essential to verify calculations by measurement results because of geometrical complexity of the reactor and so on. The comparison between measured and calculated radioactivity in the JPDR core components showed a relatively good agreement (factor of 2), and it was cleared that water content and weight ratio of steel bars to concrete materials significantly influenced the neutron flux distribution in the biological shield (factor of 2-10 error). The measured radioactivity inside of the reactor pressure vessel wall and at the inner part of the biological shield was compared in detail with the calculations to verify the methodology applied to calculations of radioisotope production. Then it was found that the radioactive inventory could be estimated accurately with combination of calculations and measurement of radioactivity in samples and dose rate distribution for planning of dismantling activities.
Working Group on Nuclear Criticality Satety Data
JAERI-Review 2001-028, 217 Pages, 2001/08
no abstracts in English
Nuclear Fuel Cycle Facility Safety Research Committee
JAERI-Tech 2001-055, 92 Pages, 2001/07
no abstracts in English
Yanagihara, Satoshi; Hatakeyama, Mutsuo; Ito, Hirokuni; Mori, Shunji*; Takagi, Akira*
Advanced Robotics, 15(3), p.293 - 300, 2001/06
Times Cited Count:1 Percentile:10.29(Robotics)Automatic measurement of building surface radioactivity must be a useful approach for decommissioning and maintenance activities in nuclear facilities. In particular, in the final step of decommissioning a nuclear power plant, it is essential to confirm that there is no effective radioactivity on building surfaces by measurement. However, experience showed that hands-on measurement using conventional detectors requires a great deal of labor-hours for all building surfaces in relatively large facilities. To realize the automatic measurement of building surface radioactivity, a mobile robot equipped with highly sensitive surface detectors has been developed; it can move automatically based on route plans to measure radioactivity on concrete floors and walls. In the development of this system, efforts were especially made to realize accurate robot motions by applying self-position identification system in consideration of the fact that the measurement should cover all the surfaces of planned areas with minimum overlap.
Tsukamoto, Michio; Takada, Junichi; Koike, Tadao; Watanabe, Koji*; Miyata, Teijiro*; Nishio, Gunji*; Murata, Mikio*; Uchiyama, Gunzo
JAERI-Tech 2001-031, 47 Pages, 2001/03
no abstracts in English
Myodo, Masato; Okane, Shogo; Miyajima, Kazutoshi
JAERI-Tech 2001-025, 59 Pages, 2001/03
no abstracts in English
Motooka, Takafumi; Terakado, Shogo; Koya, Toshio; Hamada, Shozo; Kiuchi, Kiyoshi
JAERI-Tech 2001-023, 29 Pages, 2001/03
no abstracts in English
Tachibana, Mitsuo; Shiraishi, Kunio; Yanagihara, Satoshi
JAERI-Tech 2001-014, 42 Pages, 2001/03
In the JPDR dismantling demonstration project, the dismantling activities were conducted for the purpose of verification of remote dismantling machines and collection of various kinds of data on work activities. These lessons were categorized into safety consideration, waste treatment and work efficiency by analyzing the data on work activities. Exemplified are necessities of facility information, efficiency of mock-up tests for evaluation of remote dismantling procedures. There will be useful for implementing other decommissioning projects in safe and efficiency. This report describes the measure taken for remote dismantling activities and the lessons learned from the dismantling activities.
Abe, Hitoshi; Tashiro, Shinsuke; Koike, Tadao; Okagawa, Seigo; Uchiyama, Gunzo
JAERI-Research 2001-027, 20 Pages, 2001/03
no abstracts in English
Iguchi, Tadashi; Ito, Hideo; Kiuchi, Toshio; Watanabe, Hironori; Kimura, Mamoru*; Anoda, Yoshinari
JAERI-Data/Code 2001-013, 502 Pages, 2001/03
no abstracts in English
Fukui, Toshiki; Nakashio, Nobuyuki; Isobe, Motoyasu; Otake, Atsushi*; Wakui, Takuji*; Hirabayashi, Takakuni*; Nakashima, Mikio
JAERI-Review 2000-033, 82 Pages, 2001/02
no abstracts in English
Nakashio, Nobuyuki; Isobe, Motoyasu; Wakui, Takuji*; Iwata, Keiji*; Kibayashi, Tatsuyuki*; Kanazawa, Katsuo; Fukui, Toshiki; Otake, Atsushi*; Nakashima, Mikio; Hirabayashi, Takakuni*
JAERI-Research 2001-001, 19 Pages, 2001/02
no abstracts in English
Yabuuchi, Noriaki; Takahashi, Masao*; Nakazawa, Toshio; Sato, Kazuo*; Shimazaki, Junya; Ochiai, Masaaki
JAERI-Research 2000-064, 76 Pages, 2001/02
no abstracts in English
Yabuuchi, Noriaki; Takahashi, Masao*; Nakazawa, Toshio; Sato, Kazuo*; Shimazaki, Junya; Ochiai, Masaaki
JAERI-Research 2000-063, 69 Pages, 2001/02
no abstracts in English
Takeda, Tetsuaki; Iwatsuki, Jin*
JAERI-Research 2000-057, 17 Pages, 2001/01
no abstracts in English
Onizawa, Kunio; Suzuki, Masahide
Proceedings of Asian Pacific Conference on Fracture and Strength '01(APCFS '01) and International Conference on Advanced Technology in Experimental Mechanics '01 (ATEM '01), p.140 - 145, 2001/00
In the structural integrity assessment of reactor pressure vessel, fracture toughness values are estimated by assuming that the radiation effect on fracture toughness is equivalent to that on Charpy properties. Therefore, it is necessary to establish the correlation between both properties especially on irradiation embrittlement. In this paper, we present the fracture toughness data obtained by applying the master curve approach that was adopted recently in the ASTM test method. Materials used in this study are five ASTM A533B class 1 steels and one weld metal. Neutron irradiation for Charpy-size specimens as well as standard Charpy-v specimens was carried out at the Japan Materials Testing Reactor. The shifts of the reference temperature on fracture toughness due to neutron irradiation are evaluated. Correlation between the fracture toughness reference temperature and Charpy transition temperature is established. Based on the correlation, the optimum test temperature for fracture toughness testing and the method to determine a lower bound fracture toughness curve are discussed.
Nuclear Technology and Education Center
JAERI-Conf 2000-014, 202 Pages, 2000/12
no abstracts in English