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Hirakawa, Moe*; Kikuchi, Yuichiro*; Sakai, Takaaki*; Tanaka, Masaaki; Ohshima, Hiroyuki
Proceedings of 26th International Conference on Nuclear Engineering (ICONE-26) (Internet), 8 Pages, 2018/07
Gas entrainment (GE) from cover gas is one of key issue for Sodium-cooled fast reactors to prevent unexpected effects to core reactivity. By using a computational fluid dynamics (CFD) code, analyses have been conducted to estimate the drifting vortexes on water experiments which were generated as wake vortexes behind a plate obstacle in the circulating water channel. In this paper, the results of comparison between experiments and analyses were discussed and the gas core lengths from the surface vortexes were evaluated by using the evaluation tool named StreamViewer developed by Japan Atomic Energy Agency.
; ; *; Yamaguchi, Akira
JNC TN9400 2000-109, 96 Pages, 2000/11
JNC-TN9400-2000-109.pdf:9.56MB
Numerical calculations were carried out for a free surface sloshing, a thermal stratification, a thermal striping, and a natural convection as key phenomena of in-vessel thermohydraulics in future fast reactor systems with various fluids as coolants. This numerical work was initiaied based on a recognition that the fundamental characteristics of the phenomena have been unsolved quantitatively in the use of various coolants. From the analysis for the phenomena, the following results were obtained. [Free Surface Sloshing phenomena] (1)Ther is no remarkable difference betweeen liquid sodium and luquid Pb-Bi in characteristics of internal flows and free surface charatristics based on Fr number. (2)the AQUA-VOF code has a potentiall enough to evaluate gas entrainment behavior from the free surface including the internal flow characteristics. [thermal Stratification Phenomena] (1)On-set position of thermal entainment process due to dynamic vortex flows was moved to downstream direction with decreasing of Ri number. 0n the other hand, the position in the case of C0
gas was shifted to upstream side with decreasing of Ri number. (2)Destruction speed of the thermal stratyification interface was dependent on thermal diffusivity as fluid properties. therefor it was concluded that an elimination method is necessary for the interface generated in C0 gas. [thermal Striping Phenomena] (1)Large amplitudes of fluid temperature fluctuations was reached to down stream area in the use of CO gas, due to larger fluid viscosity and smaller thermal diffusivity, compared with liquid sodium and liquid Pb-Bi cases. (2)To simulate thermal striping conditions such as amplitude and frequency of the fluid temperature fluctuations, it isnecessary for coincidences of Re number for the amplitude and of velocity value for the frequency, in various coolants. [Natural Convection Phenomena] (1)Fundamental behavior of the natural convection in various coolant follows buoyant jet ....
*; Okamoto, Koji*; *; Fumizawa, Motoo
Nihon Kikai Gakkai Rombunshu, B, 63(615), p.82 - 89, 1997/11
no abstracts in English
Watanabe, Norio
JAERI-M 94-076, 97 Pages, 1994/06
no abstracts in English
*; *; Akiyama, Mamoru*; Fumizawa, Motoo
Nihon Kikai Gakkai Rombunshu, B, 60(569), p.113 - 118, 1994/01
no abstracts in English
*; Fumizawa, Motoo
Kashika Joho Gakkai-Shi, 13(SUPPL.1), p.265 - 268, 1993/07
no abstracts in English
Watanabe, Norio; Hirano, Masashi
Journal of Nuclear Science and Technology, 29(12), p.1212 - 1223, 1992/12
no abstracts in English
Watanabe, Norio; Hirano, Masashi;
JAERI-M 91-143, 173 Pages, 1991/09
no abstracts in English
Matsushita, Kentaro; Ito, Kei*; Ezure, Toshiki; Tanaka, Masaaki
no journal, ,
In a sodium-cooled fast reactor, from the viewpoint of prevention of core reactivity disturbance, it is important to evaluate the bubbles and dissolved gas behavior in the primary coolant system due to gas entrainment. For this reason, a numerical simulation code SYRENA for bubble and dissolved gas behavior analysis in the fast reactor primary coolant system has been developed in JAEA. In this study, a flow network model of SYRENA for tank type reactor was constructed and numerical simulations aiming to compare the bubble behavior characteristics in the loop type reactor and the tank type reactor was performed as a part of the fundamental validations of the flow network model of SYRENA. As the result, it was clarified that the differences regarding the bubbles and dissolved gas behavior between two different type reactors were indicated.
