Unified mercury radioactivity monitoring system at J-PARC and its operation experiences

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

https://doi.org/10.7566/JPSCP.33.011099

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.

Generation of radioisotopes with accelerator neutrons by deuterons

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

https://doi.org/10.7566/JPSJ.82.064201

Development of remote controlled ion milling device

Honda, Junichi; Matsui, Hiroki; Harada, Akio; Obata, Hiroki; Tomita, Takeshi

JAEA-Technology 2012-021, 17 Pages, 2012/07

JAEA-Technology-2012-021.pdf:4.17MB

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.

Commentaries for third secondary national examination on fiscal 2010 for the professional engineer of nuclear and radiation; Commentaries (Part 1) including key point for elective examinations

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

http://ci.nii.ac.jp/naid/40017411146

no abstracts in English

PIE technique of fuel cladding fracture toughness test

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

Hydrogen concentration measurement in fuel cladding by backscattered electron image analysis

Onozawa, Atsushi; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu

JAEA-Technology 2006-010, 19 Pages, 2006/03

JAEA-Technology-2006-010.pdf:2.3MB

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.

Development of pellet melting temperature measuring technique; Melting temperature measuring technique for small sample

Harada, Katsuya; Nakata, Masahito; Harada, Akio; Nihei, Yasuo; Yasuda, Ryo; Nishino, Yasuharu

JAERI-Tech 2004-034, 13 Pages, 2004/03

JAERI-Tech-2004-034.pdf:0.69MB

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.

X-ray diffraction and Eu-Mssbauer spectroscopic study of the HfEuO()(0x1.0) system

Harada, Daijitsu*; Hinatsu, Yukio*; Masaki, Nobuyuki; Nakamura, Akio

Journal of the American Ceramic Society, 85(3), p.647 - 652, 2002/03

https://doi.org/10.1111/j.1151-2916.2002.tb00145.x

no abstracts in English

Revaporization of CsI aerosol in a horizontal straight pipe in a severe accident condition

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

https://doi.org/10.13182/NT01-A3186

no abstracts in English

Evaluation of high temperature tensile and greep properties of light water reactor coolant piping materials for severe accident analyses

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

https://doi.org/10.3327/jnst.37.518

no abstracts in English