Study on bubble and dissolved gas behavior in liquid sodium; Modeling and evaluation of gas behavior in pool type sodium-cooled fast reactors

Matsushita, Kentaro ; Ito, Kei*; Ezure, Toshiki ; Tanaka, Masaaki  

A numerical simulation code named SYRENA has been developed in JAEA to analyze the behavior of entrained bubbles and dissolved gas in the primary coolant of sodium-cooled fast reactor (SFR). In the present study, a flow network model for a pool-type SFR was newly developed in SYRENA and the non-condensable gas behavior in the pool type SFR was analyzed. A dipped-plate (D/P) model was introduced into the flow network to investigate influences of D/P installation on the non-condensable behavior in the pool-type reactor. A parametric study was performed on the exchange flow rate through the D/P and the gas entrainment rate at the free surface existing above the D/P. The non-condensable gas behavior under various flow conditions, e.g. gas entrainment rate condition, was obtained. Especially, it was observed that the bubble volume in the primary coolant system changed with the exchange flow rate though the change ratio is dependent on the gas entrainment.