Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Mo/
Tc generator by (n, 
) method, 4Fujita, Yoshitaka; Seki, Misaki; Ngo, M. C.*; Do, T. M. D.*; Hu, X.*; Yang, Y.*; Takeuchi, Tomoaki; Nakano, Hiroko; Fujihara, Yasuyuki*; Yoshinaga, Hisao*; et al.
KURNS Progress Report 2021, P. 118, 2022/07
no abstracts in English
Nakano, Hiroko; Fuyushima, Takumi; Tsuguchi, Akira*; Nakamura, Mutsumi*; Takeuchi, Tomoaki; Takemoto, Noriyuki; Ide, Hiroshi
JAEA-Technology 2022-007, 34 Pages, 2022/06
JAEA-Technology-2022-007.pdf:3.35MB
In order to investigate the phenomenon of stress corrosion cracking (SCC) for structural materials at the light water reactor (LWR), it is important to manage a water quality for simulating high-temperature and high-pressure water. Generally, dissolved hydrogen (DH) concentration in water loop has been controlled by the bubbling method of pure hydrogen gas or standard gas with high hydrogen concentration. However, it is necessary to equip the preventing hydrogen explosion in the area installed experimental apparatus. In general, in order to prevent accident by hydrogen, it is required to take measures such as limiting the amount of leakage, eliminating hydrogen, shutting off the power supply, and suppressing combustion before an explosion occurs. Thus, the dissolved hydrogen concentration control apparatus by electrolysis method has been developed which has two electrolysis cells to control DH concentration by electrolyzing water loop. In this study, small basic experimental devices were set up. The preliminary data were acquired regarding the simple performance of two electrolysis cells and the change of DH concentration in circulation. Based on the preliminary data, the dissolved hydrogen concentration control apparatus was designed to be connected to the high-temperature and high-pressure water loop test equipment. This report describes the test results with the small basic experimental devices for the design of the dissolved hydrogen concentration control apparatus.
Seki, Misaki; Fujita, Yoshitaka; Fujihara, Yasuyuki*; Zhang, J.*; Yoshinaga, Hisao*; Sano, Tadafumi*; Hori, Junichi*; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; et al.
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 29(1), p.2 - 9, 2022/06
no abstracts in English
Shibata, Hiroshi; Takeuchi, Tomoaki; Seki, Misaki; Shibata, Akira; Nakamura, Jinichi; Ide, Hiroshi
JAEA-Data/Code 2021-018, 42 Pages, 2022/03
JAEA-Data-Code-2021-018.pdf:2.78MB
JAEA-Data-Code-2021-018-appendix(CD-ROM).zip:0.15MB
Japan Materials Testing Reactor (JMTR) in Oarai Research and Development Institute of the Japan Atomic Energy Agency has been developing various reactor materials, irradiation techniques and instruments for more than 30 years. Among them, the development of self-powered neutron detectors (SPNDs) and gamma detectors (SPGDs) has been carried out, and several research results have been reported. However, most of the results are based on the design study of the detector development and the results of in-core irradiation tests and gamma irradiation tests using Cobalt-60. In this report, a numerical code is developed based on the paper "Neutron and Gamma-Ray Effects on Self-Powered In-Core Radiation Detectors" written by H.D. Warren and N.H. Shah in 1974, in order to theoretically evaluate the self-powered radiation detectors.
Omori, Takazumi; Otsuka, Kaoru; Endo, Yasuichi; Takeuchi, Tomoaki; Ide, Hiroshi
JAEA-Review 2021-015, 57 Pages, 2021/11
JAEA-Review-2021-015.pdf:6.3MB
The JMTR reactor facility was selected as a decommissioning one in the Medium/Long-Term Management Plan of JAEA Facilities formulated on April 1, 2017. Therefore, the decommissioning plan was submitted to Nuclear Regulation Authority on September 18, 2019, and the approval was obtained on March 17, 2021 after two amendments. Currently, preparations for decommissioning are underway. The JMTR reactor facility has been aged for more than 50 years since the first criticality in March 1968. However, some of the water piping systems has not been updated since its construction, and there is a possibility of pipe wall thinning due to corrosion, etc. Therefore, the integrity of the water piping was investigated for the facilities that circulate cooling water and pump radioactive liquid waste. In this investigation, the main circulation system of the reactor primary cooling system, the pool canal circulation system, the CF pool circulation system, the drainage system of the liquid waste disposal system, and the hydraulic rabbit irradiation system of the main experimental facility were measured for the pipe wall thickness using the Ultrasonic Thickness Measurement (UTM) method. These values satisfied the technical standards for research and test reactor facilities. No loss of integrity is expected to occur during the upcoming decommissioning period. In the future, we will periodically confirm that there is no wall thinning in the piping of the cooling water circulation and the water transmission system during the decommissioning period by using this result as basic data.
Hirota, Noriaki; Shibata, Hiroshi; Takeuchi, Tomoaki; Otsuka, Noriaki; Tsuchiya, Kunihiko
Journal of Nuclear Science and Technology, 57(12), p.1276 - 1286, 2020/12
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The influence of materials of mineral-insulated (MI) cables on their electrical characteristics upon exposure to high-temperature conditions was examined via a transmission test, in the objective of achieving the stability of the potential distribution along the cable length. Occurrence of a voltage drop along the cable was confirmed for aluminum oxide (Al
O
) and magnesium oxide (MgO), as insulating materials of the MI cable. A finite-element method (FEM)-based analysis was performed to evaluate the leakage in the potentials, which was found at the terminal end. Voltage drop yields by the transmission test and the analysis were in good agreement for the MI cable of AlO and MgO materials, which suggests the reproducibility of the magnitude relationship of the experimental results via the FEM analysis. To suppress the voltage drop, the same FEM analysis was conducted, the diameter of the core wires (
) and the distance between them (
) were varied. Considering the variation of , the potential distribution in the MI cable produced a minimum voltage drop corresponding to a ratio 
of 0.35, obtained by dividing with that of the insulating material (
). In case of varying , a minimum voltage drop was l/ of 0.5.
Seki, Misaki; Nakano, Hiroko; Nagata, Hiroshi; Otsuka, Kaoru; Omori, Takazumi; Takeuchi, Tomoaki; Ide, Hiroshi; Tsuchiya, Kunihiko
Dekomisshoningu Giho, (62), p.9 - 19, 2020/09
Japan Materials Testing Reactor (JMTR) has been contributing to various research and development activities such as the fundamental research of nuclear materials/fuels, safety research and development of power reactors, and radioisotope production since the beginning of the operation in 1968. JMTR, however, was decided as a one of decommission facilities in April 2017 and it is taken an inspection of a plan concerning decommissioning because the performance of JMTR does not confirm with the stipulated earthquake resistance. As aluminum and beryllium are used for the core structural materials in JMTR, it is necessary to establish treatment methods of these materials for the fabrication of stable wastes. In addition, a treatment method for the accumulated spent ion-exchange resins needs to be examined. This report describes the overview of these examination situations.
Takeuchi, Tomoaki; Otsuka, Noriaki; Nakano, Hiroko; Iida, Tatsuya*; Ozawa, Osamu*; Shibagaki, Taro*; Komanome, Hirohisa*; Tsuchiya, Kunihiko
QST-M-16; QST Takasaki Annual Report 2017, P. 67, 2019/03
no abstracts in English
Takeuchi, Tomoaki; Otsuka, Noriaki; Watanabe, Takashi*; Tanaka, Shigeo*; Ozawa, Osamu*; Komanome, Hirohisa*; Ueno, Shunji*; Tsuchiya, Kunihiko
Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11
no abstracts in English
Otsuka, Noriaki; Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Shibagaki, Taro*; Komanome, Hirohisa*
Proceedings of 2017 IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS/MIC 2017) (Internet), 3 Pages, 2018/11
no abstracts in English
Watanabe, Takashi*; Ozawa, Osamu*; Takeuchi, Tomoaki
Denki Gakkai-Shi, 138(8), p.529 - 534, 2018/08
no abstracts in English
Nakano, Hiroko; Hirota, Noriaki; Shibata, Hiroshi; Takeuchi, Tomoaki; Tsuchiya, Kunihiko
Mechanical Engineering Journal (Internet), 5(2), p.17-00594_1 - 17-00594_12, 2018/04
no abstracts in English
Otsuka, kaoru; Hanakawa, Hiroki; Nagata, Hiroshi; Omori, Takazumi; Takeuchi, Tomoaki; Tsuchiya, Kunihiko
UTNL-R-0496, p.13_1 - 13_11, 2018/03
no abstracts in English
Takeuchi, Tomoaki; Shibata, Hiroshi; Hanakawa, Hiroki; Uehara, Toshiaki*; Ueno, Shunji*; Tsuchiya, Kunihiko; Kumahara, Hajime*; Shibagaki, Taro*; Komanome, Hirohisa*
JAEA-Technology 2017-026, 26 Pages, 2018/02
JAEA-Technology-2017-026.pdf:4.0MB
Under severe accidents, high-integrity transmission techniques are necessary so as to monitor the situation of the nuclear power plant. In this study, effects of gamma irradiation up to 10
Gy on properties of optical devices were evaluated toward the development of a radiation-resistant in-water wireless transmission system using visible light. After the irradiation, for the LEDs, the total luminous flux decreased and the browning of resin lenses occurred. Meanwhile, the current-voltage characteristics hardly changed. For the PDs, the light sensitivity decreased and the browning of resin window occurred. The dark currents of PDs did not become large enough to adversely affect transmission. These results indicated that both the decreases of the total luminous flux of the LEDs and the light sensitivity of the PDs were mainly caused by not the degradation of the semiconductor parts but the browning of the resin parts by the irradiation. In addition, basic decrease behaviors of light transmission of several different types of glasses by gamma irradiation were also obtained so as to select the suitable optical windows and filters for the developing radiation-resistant in-water wireless transmission system.
Shibata, Hiroshi; Nakano, Hiroko; Suzuki, Yoshitaka; Otsuka, Noriaki; Nishikata, Kaori; Takeuchi, Tomoaki; Hirota, Noriaki; Tsuchiya, Kunihiko
JAEA-Testing 2017-002, 138 Pages, 2017/12
JAEA-Testing-2017-002.pdf:9.3MB
From the viewpoints of utilization improvement of the Japan Materials Testing Reactor (JMTR), the experimental devices have been established for the out-pile tests in the irradiation technology development building. The devices for the irradiation capsule assembly, material tests and inspections were established at first and experimental data were accumulated before the neutron irradiation tests. On the other hand, after the Great East Japan Earthquake, the repairs and earthquake-resistant measures of the existing devices were carried out. New devices and equipments were also established for the R&D program for power plant safety enhancement of the Agency for Natural Resources and Energy, Ministry of Economy, Trade and Industry (METI) and Mo/Tc production development under the Tsukuba International Strategic Zone. This report describes the outline and basic operation manuals of the devices established from 2011 to 2016 and the management points for the safety works in the irradiation technology development building.
Yatsuzuka, Junji*; Shibagaki, Taro*; Otsuka, Noriaki; Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Komanome, Hirohisa*
Bijon Gijutsu No Jitsuriyo Wakushoppu (ViEW 2017) Koen Yoshishu (USB Flash Drive), 6 Pages, 2017/12
no abstracts in English
Watanabe, Takashi*; Takeuchi, Tomoaki; Ozawa, Osamu*; Komanome, Hirohisa*; Akahori, Tomoyuki*; Tsuchiya, Kunihiko
Proceedings of 2017 International Image Sensor Workshop (IISW 2017) (Internet), p.206 - 209, 2017/05
no abstracts in English
Takeuchi, Tomoaki; Tsuchiya, Kunihiko; Komanome, Hirohisa*; Miura, Kuniaki*; Ishihara, Masahiro
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
After the accident at the Fukushima Dai-ichi (1F) Nuclear Power Plant (NPP), the Japanese Government referred to "Enhancement of instrumentation to identify the status of the reactors and PCVs", in the report of Japanese government to the IAEA ministerial conference in June 2011. In response to these provisions, a research and development of a monitoring system for NPPs situations during severe accidents started in November 2012. The objectives of the R&D are composed of radiation-resistant monitoring camera, radiation-resistant in-water transmission system, and heat-resistant signal cable. For all the three objectives, the elemental technologies have been already developed and now trial system are being fabricated and tested under simulated conditions of severe accidents. The results will enable us to determine the basic specifications of the systems and to provide the information about application limits for users.
irradiationTakeuchi, Tomoaki; Otsuka, Noriaki; Uehara, Toshiaki; Kumahara, Hajime*; Tsuchiya, Kunihiko
QST-M-2; QST Takasaki Annual Report 2015, P. 80, 2017/03
no abstracts in English
Takeuchi, Tomoaki; Nakano, Hiroko; Uehara, Toshiaki; Tsuchiya, Kunihiko
Nuclear Materials and Energy (Internet), 9, p.451 - 454, 2016/12
Times Cited Count：1 Percentile：12.01(Nuclear Science & Technology)no abstracts in English
