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Oguri, Hidetomo; Hasegawa, Kazuo; Ito, Takashi; Chishiro, Etsuji; Hirano, Koichiro; Morishita, Takatoshi; Shinozaki, Shinichi; Ao, Hiroyuki; Okoshi, Kiyonori; Kondo, Yasuhiro; et al.
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.389 - 393, 2014/10
no abstracts in English
Terunuma, Akihiro; Naito, Akira; Nemoto, Koichi; Usami, Jun; Tomii, Hiroyuki; Shiraishi, Kunio; Ito, Shinichi
JAEA-Review 2010-038, 96 Pages, 2010/09
Japan Atomic Energy Agency (JAEA) has midterm plan for decommissioning the facilities being finished their role and the facilities that became unnecessary by shifting their functions to other facilities. In the first midterm plan (from the latter half of fiscal year 2005 to fiscal year 2009), decommissioning of five facilities (Ceramic Research Facility, Plutonium Research Facility No.2, Metallurgy Research Facility, Isotope Separation Research Facility and Reprocessing Test Facility) had been carried out in order to release controlled area and dismantle the facilities in Nuclear Science Research Institute (NSRI), JAEA. The decommissioning activity for each facility had been reported to the regulatory body and municipalities. On this report, we summarize the each activity for five facilities by reviewing the reports to the regulatory body and municipalities. We also added the knowledge obtained through the activity.
Nakano, Junichi; Nemoto, Yoshiyuki; Miwa, Yukio; Usami, Koji; Tsukada, Takashi; Hide, Koichiro*
Journal of Nuclear Materials, 386-388, p.281 - 285, 2009/04
Times Cited Count:4 Percentile:30.49(Materials Science, Multidisciplinary)Crack initiation and crack growth processes of irradiation assisted stress corrosion cracking on stainless steels were studied by slow strain rate testing in oxygenated high temperature water at 561 K. In-situ observation was carried out during SSRT. Specimens of type 304 stainless steel were subjected to a solution annealing (SA), a thermally sensitization (TS), or a cold working (CW) and irradiated to 1.010 n/m (E 1 MeV) at 323 K in the Japan Material Testing Reactor (JMTR). Crack initiations were observed before the maximum stress would be reached for the CW material in in-situ observation. In fracture surface examination, the TS material exhibited almost intergranular stress corrosion cracking while mixtures of transgranular stress corrosion cracking and ductile dimple fracture were observed for the SA and the CW materials.
Kizaki, Minoru; Honda, Junichi; Usami, Koji; Ouchi, Asao*; Oeda, Etsuro; Matsumoto, Seiichiro
JAERI-Tech 2000-087, 50 Pages, 2001/02
no abstracts in English
Nishitani, Takeo; Takeuchi, Hiroshi; Barnes, C. W.*; Iguchi, Tetsuo*; Nagashima, Akira; Kondoh, Takashi; Sakasai, Akira; Itami, Kiyoshi; Tobita, Kenji; Nagashima, Keisuke; et al.
JAERI-M 91-176, 23 Pages, 1991/10
no abstracts in English
Uematsu, Mari; Ishibashi, Junichi; Usami, Shin; Nishi, Hiroshi
no journal, ,
no abstracts in English
Ito, Mitsuo; Fukaya, Hiroyuki; Ueno, Takashi; Miyata, Seiichi; Sonoda, Takashi; Usami, Hidehiko; Sakazume, Yoshinori; Kurosawa, Tatsuya; Kawasaki, Yasushi; Inagawa, Jun; et al.
no journal, ,
no abstracts in English
Morishita, Yuki; Izaki, Kenji; Kaneko, Junichi*; Higuchi, Mikio*; Tamura, Ken; Usami, Hiroshi; Kikuchi, Hiroyuki*; Utsugi, Wataru*; Takahira, Shiro*; Torii, Tatsuo
no journal, ,
We have developed new alpha particle detectors for detecting the alpha contaminations accurately and instantaneously: alpha imaging detectors and alpha dust monitors. For the development of the alpha imaging detector, we used a thin cerium-doped Gd(Ga,Al)O (Ce: GAGG) scintillator and silicon photomultipliers (SiPMs). The thin GAGG scintillator was optically coupled to a light-guide and the SiPMs for the detector fabrication. The detector showed a good energy resolution for 5.5 MeV alpha particles (13 % at the full width at half maximum (FWHM)). The detector is capable of capturing two-dimensional alpha images. This detector also has the advantage of its compact size, which enables to measure the alpha contaminations in narrow spaces. We demonstrated the actual measurement of smear samples obtained from the Fukushima Daiichi Nuclear Power Station using the developed imaging detector. Commercial alpha dust monitors with a silicon surface barrier detector (SSBD) operating at some nuclear facilities frequently produced false alarms due to environmental conditions such as humidity. For the development of the alpha dust monitor, we used a cerium-doped GdSiO (GPS) scintillator plate and a photomultiplier tube (PMT). The energy resolution for 5.5-MeV alpha particles was 12% FWHM. The count-rate of the radon progeny decreased by 77% with applying energy discrimination. The alpha dust monitor was capable of conducting alpha-particle spectroscopy even though the GPS scintillator got wet. The alpha dust monitor is an ideal choice for in places lacking temperature and humidity controls. In the presentation at the IRPA 15 conference, we will present the developments and measurement results of these alpha detectors.