Study on evaluation method for gas entrainment and vortex cavitation phenomena; Evaluation of gas entrainment behavior in large-scale test and development of proto-type evaluation method for vortex cavitation

Ito, Kei; Ezure, Toshiki ; Ohno, Shuji  ; Kamide, Hideki ; Nakamine, Yoshiaki*; Imai, Yasutomo*

In Japan Atomic Energy Agency (JAEA), various thermal hydraulics phenomena in an upper plenum region are evaluated in the study on the safety design criteria of the sodium-cooled fast reactor in Japan (JSFR). The gas entrainment (GE) from a free surface of coolant and the vortex cavitation (VC) at the H/L intake are important phenomena to be evaluated. Since these phenomena occur by the significant pressure drop in the vicinity of a vortex center, a technique to evaluate a vortex behavior is indispensable. The authors are developing a GE evaluation method using a numerical analysis and a vortex model. In this study, the evaluations are performed on the GE behavior in the 1/1.8 scaled water model test. In addition, a VC evaluation method is proposed on the basis of the GE evaluation method. As a basic validation of the VC evaluation method, the basic sub-surface vortex test in JAEA is evaluated.