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Saito, Shigeru; Kikuchi, Kenji*; Hamaguchi, Dai; Endo, Shinya; Sakuraba, Naotoshi; Miyai, Hiromitsu; Kawai, Masayoshi*; Dai, Y.*
Journal of Nuclear Materials, 450(1-3), p.27 - 31, 2014/07
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)no abstracts in English
Ioka, Ikuo; Ishijima, Yasuhiro; Usami, Koji; Sakuraba, Naotoshi; Kato, Yoshiaki; Kiuchi, Kiyoshi
Journal of Nuclear Materials, 417(1-3), p.887 - 891, 2011/10
Times Cited Count：8 Percentile：52.35(Materials Science, Multidisciplinary)Fe-25Cr-35Ni EHP alloy was developed with conducting the countermeasure for IASCC. It is composed to adjust major elements, to remove harmful impurities and so on. The specimens were irradiated at 553 K for 25000h using JRR-3. The fluence was estimated to be 1.5
10
n/m
. Type 304SS was also irradiated as a comparison material. SSRT test was conducted in oxygenated water at 561 K in 7.7 MPa. The fracture mode of EHP alloy was ductile. IGSCC was not observed in the fracture surface. On the other hand, the fraction of IGSCC on the fracture surface of type 304 was about 70%. Microstructural evolution of EHP and type 304 after irradiation was examined by TEM. The defects induced by irradiation mostly consisted of black dots and frank loops in both specimens. No void was also observed in grain and grain boundary of both specimens. There was a little difference in microstructure after irradiation. It is believed that EHP alloy is superior to type 304 in irradiation.
Sakuraba, Naotoshi; Numata, Masami; Komiya, Tomokazu; Ichise, Kenichi; Nishi, Masahiro; Tomita, Takeshi; Usami, Koji; Endo, Shinya; Miyata, Seiichi; Kurosawa, Tatsuya; et al.
JAEA-Technology 2009-071, 34 Pages, 2010/03
JAEA-Technology-2009-071.pdf:21.07MB
As a part of maintenance technology of a large-sized glove box for handling of TRU nuclides, we developed replacement technology for front acrylic panels using the bag-in/bag-out method and applied this technology to replace the deteriorated front acrylic panels at Waste Safety Testing Facility (WASTEF) in Nuclear Science Research Institute of Japan Atomic Energy Agency (JAEA). As a consequence, we could safely replace the front acrylic panels under the condition of continuous negative pressure only with partial decontamination of the glove box. We also demonstrated that the present technology is highly effective in points of safety, workability and cost as compared to the usual replacement technology for front acrylic panels of a glove box, where workers in an air-line suit replace directly the front acrylic panels in a green house.
Endo, Shinya; Numata, Masami; Ichise, Kenichi; Nishi, Masahiro; Komiya, Tomokazu; Sakuraba, Naotoshi; Usami, Koji; Tomita, Takeshi
Proceedings of 46th Annual Meeting of "Hot Laboratories and Remote Handling" Working Group (HOTLAB 2009) (CD-ROM), 6 Pages, 2009/09
For safety operation and maintenance of the large size glove box, the degraded acrylic panels of the box must be replaced by the new panels. As the conventional replacement technique, the decontamination of the glove box and installation of isolation tent are necessary to prevent the leak of contamination, because airtight condition of the box is broken down during replacement process. Therefore, the prerequisite works are required considerable manpower. The new replacement technique using bag-in / bag-out method was developed by JAEA. In this technique, for keeping the airtight condition of the box, the inside of degraded panel is covered with an airtight panel and the outside is covered over the large bag which is used to replace the acrylic panels. As the benefits of this technique, the prerequisite works are not required and the manpower is less than a third of the conventional technique.
Nakano, Masahiro; Arigane, Kenji; Okawa, Hiroshi; Suzuki, Takeshi; Kishimoto, Katsumi; Terunuma, Akihiro; Yano, Masaaki; Sakuraba, Naotoshi; Oba, Nagamitsu
JAERI-Tech 2003-072, 92 Pages, 2003/08
JAERI-Tech-2003-072.pdf:6.99MB
The decommissioning plan of the Japan Research reactor No2(JRR-2), decommissioning activities until the first half of phase-3, radioactive wastes and exposure dose of workers are described in this report. Since the first criticality in October 1960, JRR-2 had been operated about 36 years for various experiments. However, JRR-2 was permanent shutdown in December 1996 based on JAERI's long term plan, and the decommissioning of the JRR-2 was started in August 1997. Decommissioning of the JRR-2 was planed for 11 years from 1997 to 2007 and the program was divided into 4 phases. The decommissioning activities of the phase-1, phase-2 and the first half of phase-3 had already completed as planned in March 1998, February 2000, March 2002, respectively. The decommissioning activities of the later half of Phase-3 (dismantling of the reactor cooling systems) are carrying out at present time with planed 2002 and 2003 fiscal years.
Shiina, Hidenori; Usami, Koji; Sakuraba, Naotoshi; Harada, Akio; Onozawa, Atsushi; Nakata, Masahito
no journal, ,
Saito, Shigeru; Hamaguchi, Dai; Endo, Shinya; Sakuraba, Naotoshi; Miyai, Hiromitsu; Kikuchi, Kenji*; Kawai, Masayoshi*; Yong, D.*
no journal, ,
no abstracts in English
Saito, Shigeru; Kikuchi, Kenji*; Hamaguchi, Dai; Endo, Shinya; Usami, Koji; Sakuraba, Naotoshi; Miyai, Hiromitsu; Ono, Katsuto; Matsui, Hiroki; Kawai, Masayoshi*; et al.
no journal, ,
no abstracts in English
Numata, Masami; Komiya, Tomokazu; Sakuraba, Naotoshi; Usami, Koji; Kitagawa, Isamu; Tomita, Takeshi*
no journal, ,
no abstracts in English
Ichise, Kenichi; Sakuraba, Naotoshi; Suzuki, Kazuhiro; Miyata, Seiichi; Komiya, Tomokazu; Nishi, Masahiro; Kitagawa, Isamu; Numata, Masami
no journal, ,
As a part of measures to reduce radioactive wastes, which are generated during operation and maintenance of Waste Safety Testing Facility (WASTEF), we developed volume reduction equipment for 
and 
wastes. In this presentation, we report manufacture of an experimental model, its operativeness & verification of reduction effect in a mock-up test, improvements, and application to actual radioactive wastes.
