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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.
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.
Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
JAEA-Technology 2015-049, 61 Pages, 2016/03
JAEA-Technology-2015-049.pdf:14.7MB
In Japan Atomic Energy Agency, we started a research and development so as to monitor the Nuclear Plant Facilities situations during a severe accident, such as a radiation-resistant monitoring camera under a severe accident, a radiation resistant in-water transmission system for conveying the information in-core and a heat-resistant signal cable. As part of advance in a heat-resistant signal cable, we maintained to ex-core high-temperature and pressure water loop test equipment which can be simulated conditions of BWRs and PWRs for evaluation reliability and property of construction sheath materials. This equipment consists of Autoclave, water conditioning tank, water pump, high-pressure metering pump, preheater, heat exchanger and pure water purification equipment. This report describes the basic design and the results of performance tests of construction machinery and tools of ex-core high-temperature and pressure water loop test equipment.
Nakamura, Kazuya*; Yamamoto, Yusuke*; Suzuki, K.*; Takao, Tomoaki*; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi
IEEE Transactions on Applied Superconductivity, 25(3), p.4200704_1 - 4200704_4, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Takao, Tomoaki*; Kawahara, Yuzuru*; Nakamura, Kazuya*; Yamamoto, Yusuke*; Yagai, Tsuyoshi*; Murakami, Haruyuki; Yoshida, Kiyoshi; Natsume, Kyohei*; Hamaguchi, Shinji*; Obana, Tetsuhiro*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4800804_1 - 4800804_4, 2014/06
Times Cited Count：3 Percentile：21.9(Engineering, Electrical & Electronic)no abstracts in English
Takeuchi, Tomoaki; Shibata, Akira; Nagata, Hiroshi; Kimura, Nobuaki; Otsuka, Noriaki; Saito, Takashi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko
Proceedings of 3rd Asian Symposium on Material Testing Reactors (ASMTR 2013), p.52 - 58, 2013/11
In-pile instrumentation systems in present LWR's are indispensable to monitor all situations during reactor operation and reactor shut down. However, those systems did not work sufficiently under the conditions like as the severe accident at the Fukushima Dai-Ichi Nuclear Power Station. Therefore, based on the irradiation measurement technique of experiences accumulated in JMTR, the developments of reactor instrumentation systems to prevent severe core damage accident in advance have been started. The development objects are four instrumentation systems, which are a solid electrolysis type hydrogen concentration sensor, a water gauge of thermocouple type equipped with the heater, a 
-ray detector of self-powered type SPGD, and an image analysis system of Cherenkov light for quantification of in-reactor information by CCD cameras. After the developments, the in-pile verification tests of four instrumentation systems are planned at the JMTR.
Shibata, Akira; Miura, Kuniaki*; Takeuchi, Tomoaki; Otsuka, Noriaki; Nakamura, Jinichi; Tsuchiya, Kunihiko
JAEA-Technology 2013-024, 21 Pages, 2013/10
JAEA-Technology-2013-024.pdf:12.62MB
In the Fukushima-Daiichi Nuclear Power Plant Accident, the measurements of water level in pressure vessel and spent fuel pool were impossible due to station blackout, and it resulted in difficulty for countermeasures against the accidents and for understanding of the situations of reactor core after accidents. Therefore, we started to develop a new water level sensor for l with high reliability, which works with small electric power. This report describes reviews of conventional water level sensor and design and production of new water level sensor. After production of the sensor, performance tests were performed between room temperature and about 95 
C, and the it was confirmed that the sensor is able to measure water level with the accuracy of 
20 mm. As the results, a perspective to use the new water level sensor as water level indicator for spent fuel pools and reactor vessels after severe accident.
Takeuchi, Tomoaki; Shibata, Akira; Nagata, Hiroshi; Miura, Kuniaki*; Sano, Tadafumi*; Kimura, Nobuaki; Otsuka, Noriaki; Saito, Takashi; Nakamura, Jinichi; Tsuchiya, Kunihiko
Proceedings of 5th International Symposium on Material Testing Reactors (ISMTR-5) (Internet), 8 Pages, 2012/10
In-pile instrumentation systems in present LWR's are indispensable to monitor all situations during reactor operation and reactor shut down. However, those systems did not work sufficiently under the conditions of the severe accident at the Fukushima Dai-ichi (F1) Nuclear Power Plant. Based on instrumentation and irradiation experiences accumulated in JMTR, the developments of reactor instrumentation systems to prevent severe core damage accident in advance have been started. The development objects are water level gauge utilizing heating, self-powered -ray detector, hydrogen concentration gauge, and analysis system for imaging and quantification of in-reactor information using Cherenkov light.
Kizu, Kaname; Kashiwa, Yoshitoshi; Murakami, Haruyuki; Obana, Tetsuhiro*; Takahata, Kazuya*; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Hamaguchi, Shinji*; Matsui, Kunihiro; Nakamura, Kazuya*; et al.
Fusion Engineering and Design, 86(6-8), p.1432 - 1435, 2011/10
Times Cited Count：8 Percentile：53.37(Nuclear Science & Technology)In JT-60SA, central solenoid (CS) and plasma equilibrium field (EF) coils are procured by Japan. EF coil conductors are NbTi cable-in-conduit (CIC) conductor. Delivered superconducting cables and jackets are fabricated into CIC conductors at the jacketing facility with the length of 680 m constructed in the Naka site of JAEA. The production of superconductors with 444 m in length for actual EF coils was started from March 2010. The measurements of superconducting performance like current sharing temperature (Tcs) were conducted prior to the mass production. The measured Tcs was agreed with the expectation values from strand values indicating that no degradation was happened by production process.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.44(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：8 Percentile：49.7(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Inami, Toshiya; Owada, Kenji; Kimura, Hiroyuki*; Watanabe, Masashi*; Noda, Yukio*; Nakamura, Hiroyuki*; Yamasaki, Tomoaki*; Shiga, Masayuki*; Ikeda, Naoshi*; Murakami, Yoichi
Physical Review B, 66(7), p.073108_1 - 073108_4, 2002/08
Times Cited Count：45 Percentile：84.32(Materials Science, Multidisciplinary)It has been believed for a long time that the metal-to-insulator (MI) transition of BaVS is not accompanied by any spatial order of spin and lattice. We have carried out x-ray diffraction measurements of BaVS single crystals using laboratory x-ray source as well as synchrotron radiation, and found that superlatiice reflections which double the lattice constant c exist below the transition temperature. The most porbable space group at the low-temperature insulator phase contains two in equivalent vanadium sites and thus a charge disproportionation of the vnadium ions is considered as the main cause of the MI transition.
; Neutron diffraction and scattering studyNakamura, Hiroyuki*; Yamasaki, Tomoaki*; Giri, S.*; Imai, Hideto*; Shiga, Masayuki*; Kojima, Kenji*; Nishi, Masakazu*; Kakurai, Kazuhisa*; Metoki, Naoto
Journal of the Physical Society of Japan, 69(9), p.2763 - 2766, 2000/09
Times Cited Count：61 Percentile：87(Physics, Multidisciplinary)no abstracts in English
Araki, Masanori; Ogawa, Masuro; Kunugi, Tomoaki; *; Sato, Kazuyoshi; ; *; Dairaku, Masayuki; Nakamura, Kazuyuki; ; et al.
JAERI-Tech 95-022, 89 Pages, 1995/03
no abstracts in English
Oka, Kiyoshi; Nakamura, Tetsuya*; Ueda, Hirohisa*; Toriya, Tomoaki*; Tsumanuma, Koji*; Naganawa, Akihiro*; Watanabe, Shinsuke*; Ishiyama, Akihiko*; Yamashita, Hiromasa*; Chiba, Toshio*
no journal, ,
no abstracts in English
Chen, Y.*; Kaneta, Yasunori*; Geng, H. Y.*; Shang, J. C.*; Iwasawa, Misako*; Onuma, Toshiharu*; Sonoda, Takeshi*; Ichinomiya, Takashi*; Suzudo, Tomoaki; Itakura, Mitsuhiro; et al.
no journal, ,
The outcome of the New Crossover Project Study is outlined. The computational results includes the ab-initio study, molecular dynamics, statistical dynamics/thermal dynamics and meso-scopic modeling, and the experimental results given by an accelerator is also mentioned. Finally, we mention the future plans and the problems.
Murakami, Haruyuki; Matsui, Kunihiro; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Okuno, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Imagawa, Shinsaku*; Mito, Toshiyuki*; et al.
no journal, ,
no abstracts in English
Murakami, Haruyuki; Kizu, Kaname; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Obana, Tetsuhiro*; Takahata, Kazuya*; Hamaguchi, Shinji*; Yanagi, Nagato*; Imagawa, Shinsaku*; Mito, Toshiyuki*; et al.
no journal, ,
no abstracts in English
Nogiwa, Kimihiro; Onitsuka, Takashi; Takeuchi, Tomoaki; Abe, Teruyoshi; Sakakibara, Yasuhide; Horie, Kaoru; Nakamura, Takahisa
no journal, ,
no abstracts in English
Kawahara, Yuzuru*; Yamamoto, Yusuke*; Nakamura, Kazuya*; Takao, Tomoaki*; Yagai, Tsuyoshi*; Murakami, Haruyuki; Yoshida, Kiyoshi; Natsume, Kyohei*; Hamaguchi, Shinji*; Obana, Tetsuhiro*; et al.
no journal, ,
no abstracts in English
