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Aizawa, Kosuke; Tsuji, Mitsuyo; Kobayashi, Jun; Kurihara, Akikazu; Miyake, Yasuhiro*; Nakane, Shigeru*; Ishida, Katsuji*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Sustainable Clean Energy for the Future (FR22) (Internet), 10 Pages, 2022/04
In sodium-cooled fast reactors (SFRs), optimizing the design and operate decay heat removal systems (DHRSs) is important for safety enhancement against severe accidents that could lead to core melting. The natural circulation phenomena in a reactor vessel during operating a DHRS were clarified by conducting water experiments using a 1:10 scale experimental facility (PHEASANT) simulating the reactor vessel of loop-type SFRs. In this study, we investigated the natural circulation phenomena under conditions of operating the dipped-type DHX and RVACS using the results of temperature and particle image velocimetry (PIV) measurements, respectively. Furthermore, the effects of temperature fluctuation on the PIV measurement were quantitatively evaluated.
Ono, Ayako; Kurihara, Akikazu; Tanaka, Masaaki; Ohshima, Hiroyuki; Kamide, Hideki; Miyake, Yasuhiro*; Ito, Masami*; Nakane, Shigeru*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04
The water experiment apparatus simulating the thermal hydraulics in a reactor vessel under operating the decay heat removal systems (DHRSs) was fabricated. The theoretical evaluation for similarity and results of basic experiments show applicability for a scale model experiment of a sodium-cooled fast reactor. This paper, moreover, describes the results of flow visualization experiment under operating a dipped-type passive DHX, which is planned to be installed in both a loop type reactor and pool type reactor, and the calculation results using FLUENT comparing with the result of water experiment.
Igarashi, Minoru; Tanaka, Masaaki; Kimura, Nobuyuki; Nakane, Shigeru*; Kawashima, Shigeyo*; Hayashi, Kenji; Tobita, Akira; Kamide, Hideki
JNC TN9400 2003-092, 100 Pages, 2003/11
A water experiment for thermal hydraulics in a mixing tee was performed to investigate thermal striping phenomena. Measurement of flow velocity using particle image velocimetry and temperature measurement were carried out. Normalized power spectrum density of temperature fluctuation had same profile, when the momentum ratio of the main and branch pips is the same. From the velocity measurement test, when the momentum ratio is the same, flow pattern at mixing region shows the alomost same tendency. Temperature transfer characteristics from fluid to structure can be estimated by a constant heat transfer coefficient in time.
Igarashi, Minoru; Kawashima, Shigeyo*; Nakane, Shigeru*; Tanaka, Masaaki; Kimura, Nobuyuki; Kamide, Hideki
JNC TN9400 2003-005, 80 Pages, 2003/02
JNC-TN9400-2003-005.pdf:3.68MB
In the place where hot and cold fluids are mixed, a time and spatial temperature fluctuation occurs. When this temperature fluctuation amplitude is large, it causes high cycle thermal fatigue in surrounding structure (thermal striping phenomena). Mixing area of high and low temperature fluid exists not only in an atomic power plant but also in a general plant, then, it is significant to investigate this phenomena and also to establish an evaluation rule. In Japan Nuclear Cycle Development Institute, several experiments and the improvement of the analysis methods have been carried out to understand thermal striping phenomena and also to construct an evaluation rule, which can be applied to design. Water Experiment on Fluid Mixing in T-pipe with Long Cycle Fluctuation (WATLON), aiming at examining thermal striping phenomena in a mixing tee, is performed to investigate key factors of mixing phenomena. In this study, in order to investigate the fluid mixing phenomena, temperature and flow velocity distribution were measured by movable thermocouple tree and particle image velocimetory (PIV). And the analysis using a in-house direct numerical simulation (DNS) code, DINUS-3 was performed to understand applicability of the analytical method in mixing tee. The temperature and velocity fields obtained from the DINUS-3 were in good agreement with the experimental results. And the prominent frequency of temperature fluctuation was also in good agreement. The DINUS-3 calculation simulated vortex structure in the wake region behind the branch pipe jet. The results of analysis showed that a Karman vortex generated in the wake region behind the branch pipe jet influenced the temperature fluctuation behavior in the mixing tee. And the analytical results revealed that the vortex generated in the wake region behind the branch pipe jet showed the 3-dimensional behavior.
Kobayashi, Jun; Sato, Hiroyuki; Kimura, Nobuyuki; Kamide, Hideki; Nakane, Shigeru*
no journal, ,
no abstracts in English
Okabe, Toshihiro*; Ono, Hiroyuki*; Hatayama, Ichiro*; Waguri, Atsushi*; Sawada, Yuzuru*; Tsugawa, Hidehito*; Ichida, Tadao*; Nakane, Akio*; Sano, Teruo*; Tanaka, Kazuaki*; et al.
no journal, ,
Hiroki, Akihiro; Iwanaga, Shigeru; Tamada, Masao; Okabe, Toshihiro*; Ono, Hiroyuki*; Hatayama, Ichiro*; Waguri, Atsushi*; Sawada, Yuzuru*; Nakane, Akio*; Sano, Teruo*
no journal, ,
Aomori Hiba oil is oil of the natural thing origin extracted from the sawdust generated during lumbering of Aomori Hiba that is the tree in Aomori prefecture by the steam distillation. The extracted Aomori Hiba oil has excellent antibacterial and insecticidal effects. To heighten the added value of the Aomori Hiba oil, the water-soluble nano-hiba oil with about 10 nm of particle size was developed by applying emulsification technology to the oil. The emulsified Aomori Hiba oils showed no signs of phase separation and remained intact even six months after its preparation. Since the nano-hiba oil can be sprayed quickly, antibacterial examinations were carried out to explore potential applications in preventions of hospital infection and damages caused by blight and insect in agricultural environments. Furthermore, a novel antibacterial material composed of nano-hiba oil and water-absorption biodegradable gel was investigated. Hydroxypropyl cellulose (HPC) hydrogels as support materials for the nano-hiba oil were prepared by irradiating to paste-like aqueous solutions of HPC. Degree of swelling of the HPC hydrogels was influenced by compositions in nano-hiba oils. Subsequently, absorbability in nano-hiba oil as well as the antibacterial effects was evaluated. The HPC hydrogels swollen in the nano-hiba oil mixing silica showed excellent antibacterial effect up to three weeks. Therefore, it was suggested that the hydrogels containing nano-hiba oil are suitable as antibacterial materials.
Ono, Ayako; Kurihara, Akikazu; Tanaka, Masaaki; Ohshima, Hiroyuki; Miyake, Yasuhiro*; Ito, Masami*; Nakane, Shigeru*
no journal, ,
Thermal-hydraulic phenomena driven by natural circulation in a reactor vessel was investigated by using scaled model water experiments simulating a reactor vessel in order to enforce of safety and optimize design and operation of decay heat removal systems under normal operation and severe accident conditions. Through the flow visualization tests, the behavior of cold fluid from the dipped-type heat exchanger and cooling process of the core and debris in the vessel were revealed.
Aizawa, Kosuke; Tsuji, Mitsuyo; Kobayashi, Jun; Kurihara, Akikazu; Nakane, Shigeru*; Ishida, Katsuji*
no journal, ,
Thermal-hydraulic phenomena driven by natural circulation in a reactor vessel was investigated by using scaled model water experiments simulating a reactor vessel in order to enforce of safety and optimize design and operation of decay heat removal systems under normal operation and severe accident conditions. This paper shows temperature measurement results of natural convection flow field in reactor vessel simulating operation of reactor vessel auxiliary cooling system. In addition, it is shown that the affect of dispersal condition of molten fuel on temperature distribution in reactor vessel.
Tsuji, Mitsuyo; Aizawa, Kosuke; Kobayashi, Jun; Kurihara, Akikazu; Nakane, Shigeru*; Ishida, Katsuji*
no journal, ,
Thermal-hydraulic phenomena caused by the natural circulation in a reactor vessel were investigated using scaled model water experiments simulating the reactor vessel in order to enhance safety and optimize the design and operation of decay heat removal systems under normal operation and severe accident conditions. This report shows the measurement results of temperature and PIV of natural convection flow field in the reactor vessel simulating an operation of dipped type direct heat exchanger. In addition, it is shown that the effect of dispersal condition of molten fuel on natural convection flow field in the reactor vessel.
Aizawa, Kosuke; Tsuji, Mitsuyo; Kobayashi, Jun; Kurihara, Akikazu; Nakane, Shigeru*; Onuma, Hideyoshi*
no journal, ,
Thermal-hydraulic phenomena driven by natural circulation in a reactor vessel was investigated by using scaled model water experiments simulating a reactor vessel to enforce the safety and to optimize the design and operation of decay heat removal systems under normal operation and severe accident conditions. This paper shows the results of transient behavior under operations of dipped-type DHX and penetrated-type DHX to clarify the effect of operating multiple decay heat removal systems on natural circulation phenomena in reactor vessel. From the experimental results, it was confirmed that the maximum temperature temporarily increased compared to the maximum temperature in natural circulation steady state by operating the second DHX after the natural circulation steady state was maintained under the first DHX operation.