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Takata, Takashi*; Konaka, Yuji*; Yamaguchi, Akira*; Ito, Kei; Ohno, Shuji; Ohshima, Hiroyuki
Proceedings of 9th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-9) (CD-ROM), 7 Pages, 2014/11
In this paper, a model of bubble transport at entrance nozzle has been developed based on theoretical and computational methods. For this purpose, a three-dimensional analysis of dynamic bubbles behavior has been carried out by using one-way bubble tracking method which is specified to a bubble flow under a low void fraction. A commercial CFD tool, FLUENT Ver. 6.3.26 is used for three-dimensional flow field analyses. Then the gas accumulation at a high pressure plenum (HPP) of sodium-cooled fast rector has been quantitatively-assessed by implementing the developed model in SYRENA code. Furthermore, gas elimination (bubble removal) systems have been considered and the quantitatively-assessment has been carried out in order to investigate the effect of each measure to the accumulation of gas at the HPP.
Konaka, Yuji*; Takata, Takashi*; Yamaguchi, Akira*; Ito, Kei; Ohshima, Hiroyuki
Proceedings of 8th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-8) (USB Flash Drive), 7 Pages, 2012/12
Bubbles of inert gases exist in a primary coolant system of sodium-cooled fast reactor. Those bubbles may cause increase of reactivity in the core and cavitation erosion and so on. Therefore it is necessary from the viewpoint of reactor safety to understand the dynamic behavior of the bubbles. In this study, the model of gas transport at the entrance nozzle has been developed using a non-dimensional correlation based on a three-dimensional analysis of dynamic bubbles behavior. As a result, it has been demonstrated that the bubble behavior is influenced by the sodium flow field, bubble radius and the shape of the entrance nozzle. The authors have also developed a correlation for the gas behavior based on the dimensionless number which corresponds to the geometric, the buoyancy and the drag force effects acting on the bubble.