Experimental study of gas entrainment phenomena in sodium cooled fast reactor by 1/1.8 scale partial model

Ezure, Toshiki ; Kimura, Nobuyuki; Miyakoshi, Hiroyuki; Kamide, Hideki 

Gas entrainment (GE) at free surface is one of the significant issues for the design of Japan Sodium Cooled Fast Reactor (JSFR). It is required to evaluate the occurrence of GE in the operating condition of JSFR. In the present study, a water experiment was performed in a large-scaled partial upper plenum model to simulate the startup operation of JSFR, where the sodium level was lower than in the rated condition. The onset condition of GE was clarified by the visualization of free surface. Vertical velocity distribution was also measured in order to grasp the mechanism of GE. As a result, it was confirmed that GE did not occur in the startup condition of JSFR.