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Harada, Masahide; Sekijima, Mitsuaki*; Morikawa, Noriyuki*; Masuda, Shiho; Kinoshita, Hidetaka; Sakai, Kenji; Kai, Tetsuya; Kasugai, Yoshimi; Muto, Giichi*; Suzuki, Akio*; et al.
JPS Conference Proceedings (Internet), 33, p.011099_1 - 011099_6, 2021/03
In MLF at J-PARC, a unified mercury radioactivity monitor (UHAM) is installed to find an indication of failure of the mercury target and loop system by detecting radioactive materials leaked from the system with a -ray energy analysis with Germanium semi-conductor detectors (Ge detectors). It is composed of three units of sampling port and radiation monitors: (1) HAM for interstitial helium gas layer between the mercury vessel and surrounding water shroud of the mercury target, (2) CAM for atmosphere in the hot cell where the target loop is operated and (3) VAM for helium gas in the helium vessel where the target vessel is installed. Once any leakages of radioactive materials are detected, an alarm signal is issued immediately to the accelerator control system to stop beam operation. Software and hardware have been upgraded yearly. For example, two Ge detectors are used for HAM for redundancy, NaI Scintillation detectors are also used as supplemental for the Ge detector to keep availability of the system for high counting rate event. In April 2015, the UHAM activated when a small water coolant leakage from the water shroud of the mercury target occurred. VAM detected an abnormal increase of the counting rate in the helium vessel. It was also indicated that the measured radioactive nuclides were generated from the activation of the coolant (water) in the water shroud and not from the mercury.
Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.
Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00
no abstracts in English
Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sonoda, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro*; Tsukada, Kazuaki; et al.
Journal of the Physical Society of Japan, 82(6), p.064201_1 - 064201_7, 2013/06
Times Cited Count:43 Percentile:85.20(Physics, Multidisciplinary)Honda, Junichi; Matsui, Hiroki; Harada, Akio; Obata, Hiroki; Tomita, Takeshi
JAEA-Technology 2012-022, 35 Pages, 2012/07
The advanced utilization of Light Water Reactor (LWR) fuel is progressed in Japan to save the power generating cost and the volume of nuclear wastes. The electric power companies have been continued the approach to extend the burnup and to rise up the thermal power of the commercial fuel. The government should be accumulating the detailed information of the newest technologies to make the regulations and guidelines for the safety of the advanced nuclear fuels. The remote controlled Electron Prove Micro Analyzer attached with crystal orientation analyzer (EPMA) has been developed in Japan Atomic Energy Agency (JAEA) to evaluate the fuel behavior effected by the cladding microstructure under the accident condition. The device was modified to the airtight and earthquake resistant structure for the examination of high radioactive elements. This paper describes the specification of EPMA and the test results of the cold mock-up to confirm their performances and reliabilities.
Honda, Junichi; Matsui, Hiroki; Harada, Akio; Obata, Hiroki; Tomita, Takeshi
JAEA-Technology 2012-021, 17 Pages, 2012/07
The advanced utilization of Light Water Reactor (LWR) fuel is progressed in Japan to save the power generating cost and the volume of nuclear wastes. The electric power companies have been continued the approach to extend the burnup and to rise up the thermal power of the commercial fuel. The government should be accumulating the detailed information of the newest technologies to make the regulations and guidelines for the safety of the advanced nuclear fuels. The ion milling for post irradiation examination has been developed in Japan Atomic Energy Agency (JAEA) to investigate cladding microstructure. This device has been modified to operate the high radioactive elements remotely and have the performance of earthquake resistant. This paper describes the specification of the device which were specialized for post irradiation examination and the test results of the cold mock-up to confirm their performances and reliabilities.
Natsume, Tomohiro*; Nakano, Makoto*; Harada, Akio; Yamanaka, Atsushi; Kurihara, Ryoichi
Genshiryoku eye, 57(4), p.72 - 76, 2011/04
no abstracts in English
Sasaki, Satoru; Suto, Toshiyuki; Harada, Akio; Kurihara, Ryoichi; Yamamoto, Kazuyoshi; Tsuchida, Noboru; Shimizu, Isamu; Nomura, Toshibumi
Genshiryoku eye, 57(1), p.66 - 75, 2011/01
no abstracts in English
Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Nakata, Masahito; Kanazawa, Hiroyuki; Sagawa, Tamio
JAEA-Conf 2008-010, p.325 - 332, 2008/12
The measurement technique for hydrogen concentration using Backscattered Electron Image analysis (BEI method) had been developed by Studsvik Nuclear AB. The hydride in claddings is identified using BEIs with SEM and the hydrogen concentration is calculated from the area fractions of the hydride in those BEIs. In the RFEF, the sample polishing techniques and image processing procedure for BEI method were improved to measure the hydrogen concentration in the irradiated fuel claddings more precisely. In the previous tests using the un-irradiated fuel claddings, it is confirmed improved BEI method has high reliability. The radial and axial hydrogen concentration profiles of the irradiated fuel claddings were measured with improved BEI method. As the results of these measurements, the local hydrogen concentration could be indicated more precisely with the improved BEI method compared to the other methods for the hydrogen concentration measurement and observation.
Endo, Shinya; Usami, Koji; Nakata, Masahito; Fukuda, Takuji*; Onozawa, Atsushi; Harada, Akio; Kizaki, Minoru; Kikuchi, Hiroyuki
HPR-366, Vol.1 (CD-ROM), 10 Pages, 2007/03
no abstracts in English
Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu
JAEA-Conf 2006-003, p.212 - 221, 2006/05
In the Reactor Fuel Examination Facility (RFEF), a measuring method of hydrogen concentration by backscattered electron image analysis was improved to obtain more local hydrogen concentration data in fuel claddings. The sample preparation and image analysis procedures of this were able to measure hydrogen concentration efficiently and precisely.
Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu
JAEA-Technology 2006-010, 19 Pages, 2006/03
A measurement technique for hydrogen concentration using Backscattered Electron Image analysis (BEI method) had been developed by Studsvik Nuclear AB, Sweden. The hydrides in claddings are identified using BEIs which are imaged with Scanning Electron Microscope, and the hydrogen concentrations are calculated from the area fractions of the hydrides in the matrix. The BEI method is very useful for the measurement in local hydrogen concentrations of fuel claddings. In the Reactor Fuel Examination Facility, a sample preparation, imaging conditions of SEM and image analysis procedures for the BEI method were improved. In addition, the hydrogen concentrations obtained by the improved BEI method and Hot Vacuum Extraction (HVE) method were compared to confirm the reliability of the improved BEI method. The results showed, the improved BEI method has the same reliability as that of HVE method and can be applied for the Post-Irradiation Examination.
Harada, Akio; Sato, Tadashi*; Nakajima, Kunihisa; Komuro, Yuichi; Shiraishi, Hirotsugu*; Hattori, Takamitsu; Ikuta, Yuko; Yachi, Shigeyasu; Kushita, Kohei
JAERI-Review 2005-026, 55 Pages, 2005/09
This report provides an example of answers to the problems of the 37th Examination for the Chief Engineer of Nuclear Fuel. This examination was done as a national qualification in March 2005. Brief explanations or references are added to some answers.
Harada, Katsuya; Nakata, Masahito; Harada, Akio; Nihei, Yasuo; Yasuda, Ryo; Nishino, Yasuharu
JAERI-Tech 2004-034, 13 Pages, 2004/03
The Department of Hot Laboratories has been aiming the establishment of the melting temperature measuring technique for small samples obtained from the micro-region of irradiated fuel pellet. Due to the modification of the shape of tungsten capsule contained sample and the improvement of the detection method for melting temperature from indistinct thermal arrest point owing to small sample, it is possible to determine the melting temperature of small sample and to utilize effectively for the irradiated fuel pellet by using the existing apparatus. This paper describes the technique of the melting temperature measurement for small sample and the experimental results by using tantalum, molybdenum, hafnium oxide and un-irradiated UO pellet.
Masaki, Nobuyuki; Otobe, Haruyoshi; Nakamura, Akio; Harada, Daijitsu*; Ito, Kentaro*; Sasaki, Yoshinobu*; Hinatsu, Yukio*
Journal of Nuclear Science and Technology, 39(Suppl.3), p.217 - 220, 2002/11
no abstracts in English
Harada, Daijitsu*; Hinatsu, Yukio*; Masaki, Nobuyuki; Nakamura, Akio
Journal of the American Ceramic Society, 85(3), p.647 - 652, 2002/03
no abstracts in English
Chino, Eiichi; Maruyama, Yu; Maeda, Akio*; Harada, Yuhei*; Nakamura, Hideo; Hidaka, Akihide; Shibazaki, Hiroaki*; Yuchi, Yoko; Kudo, Tamotsu; Hashimoto, Kazuichiro*
Proceedings of the 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), p.107 - 115, 2001/06
no abstracts in English
Shibazaki, Hiroaki*; Maruyama, Yu; Kudo, Tamotsu; Hashimoto, Kazuichiro*; Maeda, Akio*; Harada, Yuhei*; Hidaka, Akihide; Sugimoto, Jun
Nuclear Technology, 134(1), p.62 - 70, 2001/04
Times Cited Count:3 Percentile:27.07(Nuclear Science & Technology)no abstracts in English
Harada, Yuhei*; Maruyama, Yu; Maeda, Akio*; Chino, Eiichi; Shibazaki, Hiroaki*; Kudo, Tamotsu; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun
JAERI-Conf 2000-015, p.309 - 314, 2000/11
no abstracts in English
Harada, Yuhei; Maruyama, Yu; Maeda, Akio*; Chino, Eiichi; Shibazaki, Hiroaki*; Kudo, Tamotsu; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun
Journal of Nuclear Science and Technology, 37(6), p.518 - 529, 2000/06
no abstracts in English
Harada, Yuhei; Maruyama, Yu; Maeda, Akio; Shibazaki, Hiroaki*; Kudo, Tamotsu; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun
Journal of Nuclear Science and Technology, 36(10), p.923 - 933, 1999/10
Times Cited Count:3 Percentile:28.69(Nuclear Science & Technology)no abstracts in English