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Wada, Yuki; Shibamoto, Yasuteru; Hibiki, Takashi*
International Journal of Heat and Mass Transfer, 239, p.126598_1 - 126598_18, 2025/04
Times Cited Count：1 Percentile：30.78(Thermodynamics)Suzuki, Kenji*; Miura, Yasufumi*; Shiro, Ayumi*; Toyokawa, Hidenori*; Saji, Choji*; Shobu, Takahisa; Morooka, Satoshi
Zairyo, 72(4), p.316 - 323, 2023/04
Ogawa, Masuro*
JAEA-Technology 2019-010, 22 Pages, 2019/07
JAEA-Technology-2019-010.pdf:1.5MB
Transition phenomena from laminar to turbulent flow are roughly classified into three categories. Circular pipe flow of the third category is linearly stable against any small disturbance, despite that flow actually transitions and transitional flow exhibits intermittency. These are among major challenges that are yet to be resolved in fluid dynamics. Thus, author proposes hypothesis as follows; "Flow in a circular pipe transitions from laminar flow because of vortices released from separation bubble forming in vicinity of inlet of pipe, and transitional flow becomes intermittent because vortex-shedding is intermittent." Present hypothesis can easily explain why linear stability theory has not been able to predict transition in circular pipe flow, why circular pipe flow actually transitions, why transitional flow actually exhibits intermittency even due to small disturbance, and why numerical analysis has not been able to predict intermittency of transitional flow in circular pipe.
Nishimura, Akihiko; Furusawa, Akinori; Takenaka, Yusuke*
AIP Conference Proceedings 2033, p.080002_1 - 080002_5, 2018/11
Times Cited Count：1 Percentile：49.46(Green & Sustainable Science & Technology)We developed a cpmpact laser maintenance device in order to access a 23 mm diameter for heat exchanger tubes of nuclear power plants. A laser instrumentation device was desighned and assembled to measure the corrosion depth at the inlet of heat exchanger tubes. This device can be applied for heat exchanger tubes in CSP where erosion or cracking might be caused by repetitive thermal induced stress.
-ray pipe-monitoring capabilities for real-time process monitoring safeguards applications in reprocessing facilitiesRodriguez, D.; Tanigawa, Masafumi; Nishimura, Kazuaki; Mukai, Yasunobu; Nakamura, Hironobu; Kurita, Tsutomu; Takamine, Jun; Suzuki, Satoshi*; Sekine, Megumi; Rossi, F.; et al.
Journal of Nuclear Science and Technology, 55(7), p.792 - 804, 2018/07
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)Nuclear material in reprocessing facilities is safeguarded by random sample verification with additional continuous monitoring applied to solution masses and volume in important tanks to maintain continuity-of-knowledge of process operation. Measuring the unique rays of each solution as the material flows through pipes connecting all tanks and process apparatuses could potentially improve process monitoring by verifying the compositions in real time. We tested this ray pipe-monitoring method using plutonium-nitrate solution transferred between tanks at the PCDF-TRP. The rays were measured using a lanthanum-bromide detector with a list-mode data acquisition system to obtain both time and energy of -ray. The analysis and results of this measurement demonstrate an ability to determine isotopic composition, process timing, flow rate, and volume of solution flowing through pipes, introducing a viable capability for process monitoring safeguards verification.
Furusawa, Akinori; Takenaka, Yusuke*; Nishimura, Akihiko; Mizutani, Haruki; Muramatsu, Toshiharu
Nihon Hozen Gakkai Dai-14-Kai Gakujutsu Koenkai Yoshishu, p.479 - 480, 2017/08
Industry development activities on applied laser research held at Fukui branch of Japan Atomic Energy Agency are reported. Industry development is inevitable in long-term vision and strategy for developing maintenance technology and establishing decommissioning technology. Fukui branch of JAEA has organized public seminar offering businesses to promote these activities and technology exchange for years. Here some examples offered in the current seminar are introduced concerning with laser technology. Finally, our goal and important point of view are discussed.
-ray pipe monitoring for comprehensive safeguards process monitoring of reprocessing facilitiesRodriguez, D.; Tanigawa, Masafumi; Mukai, Yasunobu; Isomae, Hidemi; Nakamura, Hironobu; Rossi, F.; Koizumi, Mitsuo; Seya, Michio
Proceedings of INMM 58th Annual Meeting (Internet), 9 Pages, 2017/07
Safegaurding nuclear material at reprocessing facilities utilizes sampling to verify the quantity and process monitoring to maintain continuity-of-knowledge to reduce re-verification. Solution Monitoring and Measurement Systems that determine the solution density and volume are installed at solution tanks, though this only provides indirect verification. To offset this safeguards limitation we propose measuring rays from solutions passing through the pipes and at the tanks to provide improved continuous monitoring and direct verification. This can provide both real-time flow measurements and Pu isotopic composition quantification through passive nondestructive assay. This concept was tested by recent experimental studies performed at the Japan Atomic Energy Agency's Plutonium Conversion Development Facility of flowing Pu-nitrate rays. This presentation will describe the concept details and analysis of using ray pipe monitoring as a capability for real-time safeguards verification.
Shen, X.*; Schlegel, J. P.*; Hibiki, Takashi*; Nakamura, Hideo
Proceedings of 2017 Japan-US Seminar on Two-Phase Flow Dynamics (JUS 2017), 6 Pages, 2017/06
Yamada, Fumiaki; Arikawa, Mitsuhiro*; Fukano, Yoshitaka
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
In sodium-cooled fast reactor, since the coolant does not need to be pressurized, a pipe break due to the internal pressure does not occur physically. For safety margin in Japanese prototype fast breeder reactor (Monju), the guillotine pipe break accident, i.e., loss of integrity (LOPI) has been analyzed as an extreme assumption for beyond design basis accidents (B-DBAs) in the licensing application for the permit. The cooling capability of the core was re-evaluated in this paper during a large-scale, more specifically guillotine pipe break at the primary heat transport system (PHTS) in Monju, newly considering the following latest findings: (a) Experimental data on sodium boiling in fuel assemblies, (b) Actual PHTS pump coast-down characteristics, and (c) Transient burst test data on irradiated fuel claddings. The analysis models were the validated and simulations were re-performed also using the actual Monju data such as the response time to the trip signals, etc. As a result, it was clarified that the ratio of failed fuel claddings does not exceed around 3% of all of fuel assemblies, as in the past licensing analysis. The safety has been reconfirmed to be secured without significant core damage even under an extreme assumption of a double-ended guillotine pipe break at the PHTS in Monju.
Fujimoto, Nozomu; Tachibana, Yukio; Saikusa, Akio*; Shinozaki, Masayuki; Isozaki, Minoru; Iyoku, Tatsuo
Nuclear Engineering and Design, 233(1-3), p.273 - 281, 2004/10
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)From a viewpoint of heat leakage, there were two incidents during HTTR power-rise-tests. One was a temperature rise of the primary upper shielding, and the other was a temperature rise of the core support plate. Causes of the both incidents were small amount of helium flow in structures. For the temperature rise of the primary upper shielding, countermeasures to reduce the small amount of helium flow, enhancement of heat release and installation of thermal insulator were taken. For the temperature rise of the core support plate, temperature evaluations were carried out again considering the small amount of helium flow and design temperature of the core support plate was revised. By these countermeasures, the both temperatures were kept below their limits.
Kameo, Yutaka; Nakashima, Mikio; Hirabayashi, Takakuni*
Nuclear Technology, 144(1), p.76 - 82, 2003/10
Times Cited Count：2 Percentile：18.52(Nuclear Science & Technology)Erosion behavior of stainless and carbon steel pipes by a swirling air flow containing alumina or cast-iron grit abrasive was investigated. Effects of operating conditions such as an abrasive concentration and a flow rate of air-stream on erosion ability was examined. Erosion depths of the test pipes were approximately proportional to the concentration of abrasives and exponent of flow rate of air-stream. The experimental results indicated that the present method could keep satisfactory erosion ability of abrasives even for a large size pipe. The present method was successfully applied to 
Co-contaminated specimens sampled from a pipe of the water clean-up system of the Japan Power Demonstration Reactor.
Hanawa, Satoshi; Tachibana, Yukio; Iyoku, Tatsuo; Ishihara, Masahiro; Ito, Haruhiko
JAERI-Tech 2003-064, 25 Pages, 2003/07
JAERI-Tech-2003-064.pdf:2.84MB
On the 147cycle operation, the water leakage was found at the pressure instrumentation pipe which is attached to the exit pipe of No.1 charge pump of the purification system of primary cooling system at JMTR in the Oarai establishment, JAERI. Then JMTR was shutted down manually on December 10th. It was predicted that the crack on the pressure instrumentation pipe was initiated and propagated by the cyclic load which was caused by the charge pump. Therefore, vibration and stress analyses of pressure instrumentation pipe were performed. From the vibration analysis, the natural frequency of the pressure instrumentation pipe of No.1 charge pump is between 53
58Hz, which is close to the resonance frequency of 50Hz. From the stress analysis results, total stress generated on the pressure instrumentation pipe is 112.2MPa at the natural frequency of 53Hz and 74.2Mpa at 58Hz. It was found that the stress of 112.2MPa is close to the fatigue limit of used materials.
Working Group for Investigation of Cause of Crack Initiation
JAERI-Tech 2003-060, 183 Pages, 2003/07
JAERI-Tech-2003-060.pdf:55.37MB
On December 10, 2002, the water leakage was found at the pressure instrumentation pipe attached to the exit pipe of No.1 charging pump of the purification system of a primary cooling system at JMTR, and the cracks were detected on the pressure instrumentation pipe by the visual observation. The Investigation Committee for Water Leakage from Instrumentation Pipe in JMTR was established and organized by specialists from inside and outside JAERI on December 16. In order to investigate the cause of crack initiation at the pressure instrumentation pipe, the Working Group was organized in the Department of JMTR. Visual inspection, fractgraphy test, metallographic observation and hardness test for the pressure instrumentation pipe and its weldment were carried out in the JMTR Hot Laboratory. This report summarized above data obtained by investigation on the cause of the crack initiation.
Takeda, Takeshi; Tachibana, Yukio
Nuclear Engineering and Design, 223(1), p.25 - 40, 2003/07
Times Cited Count：2 Percentile：18.52(Nuclear Science & Technology)no abstracts in English
JMTR Pressure Measurement Pipe Investigation Committee
JAERI-Review 2003-014, 117 Pages, 2003/03
JAERI-Review-2003-014.pdf:27.62MB
On December 10、2002, the leak was found at the pressure measurement pipe attached to the exit pipe of No.1 filing pump of the refining system of a primary cooling system at JMTR in Oarai Research establishment JAERI. Investigation Committee for Water Leakage from Instrumentation Pipe in JMTR was established and organized by specialists from inside and outside JAERI on December 16 and its meeting was held in public 3 times by 6th January, 2003. They investigated the cause and countermeasures of cracks, and also investigated enhancement of safety management. This is the report on the cause and countermeasures of cracks and enhancement of safety management.
Hori, Junichi; Sato, Satoshi; Yamauchi, Michinori*; Ochiai, Kentaro; Nishitani, Takeo
JAERI-Research 2003-002, 50 Pages, 2003/03
JAERI-Research-2003-002.pdf:2.21MB
D-T neutron irradiation experiments have been performed with F82H and ODS ferritic steels and the effective cross sections for 
Co productions in those materials via the sequential reactions were measured. The effective cross sections for F82H and ODS ferritic steels were about 1.5 times larger than that for iron. The distributions of effective cross sections were measured for 6 materials (iron, copper, vanadium, titanium, tungsten and lead) and F82H. The sequential reaction rates in the region close to hydrogen compound became over 20 times larger than that in material itself. In the case of F82H, the increase ratio was about 50. It was indicated that the activity for the sequential reaction product Co will reach to 3-10 
of that for primary neutron reaction product 
Mn aound the surface of a cooling pipe in a fusion reactor. The effective cross sections were estimated by using (n,xp), (p,n) reaction cross sections, proton emission spectra, proton stopping power in the material. The estimated values were compared with experimental results.
Kakudate, Satoshi; Shibanuma, Kiyoshi
Kensa Gijutsu, 7(11), p.28 - 33, 2002/11
no abstracts in English
Department of Hot Laboratories
JAERI-Tech 2002-050, 51 Pages, 2002/06
JAERI-Tech-2002-050.pdf:18.17MB
In Hamaoka Nuclear Power Station Unit-1 of Chubu Electric Power Company, a steam leak accident occurred with a pipe rupture. In order to investigate root cause of the pipe rupture, a task force was established within the Nuclear and Industrial Safety Agency (NISA). The JAERI was asked from NISA to cooperate as an independent neutral organization with NISA and perform an examination of the ruptured pipe. The JAERI examination group was formed at the Tokai Research Establishment and conducted some examinations of samples. In Dept. of Hot Laboratories, in order to respond the request of the investigation, the detailed program, various apparatuses, and technical staffs for the examinations are prepared. In this report, technical items in terms of contents of the examination, the used apparatuses, and techniques in three facilities in Dept. of Hot Laboratories (RFEF, RHL, and WASTEF) are summarized.
JAERI Working Group for Examination of the Ruptured Pipe at Hamaoka-1
JAERI-Tech 2002-045, 253 Pages, 2002/03
JAERI-Tech-2002-045.pdf:60.08MB
no abstracts in English
JAERI Working Group for Examination of the Ruptured Pipe at Hamaoka-1
JAERI-Tech 2001-094, 60 Pages, 2001/12
JAERI-Tech-2001-094.pdf:13.99MB
no abstracts in English
