Development of evaluation method for vortex cavitation onset behavior in sodium-cooled fast reactor

Ezure, Toshiki ; Ito, Kei; Kameyama, Yuri*; Kurihara, Akikazu ; Kunugi, Tomoaki*

In order to provide knowledge about applicability of vortex model based evaluation method to vortex cavitation in sodium-cooled fast reactor, the evaluation method was applied to experimental results in a small-scaled water model of advanced SFR. Furthermore, to improve the evaluation accuracy of the pressure decrease, an empirical modification of evaluation formula was proposed based on experimental results obtained in another simple geometry. As the results, time-trends of pressure decrease at a vortex center in typical cases showed fluctuation in time. Occurrences of vortex cavitation, which showed intermittent behavior, concentrated at maximal points of the time-trends of pressure decrease. In other words, the qualitative onset behavior of vortex cavitation in the small model was captured successfully by the current evaluation formula. More importantly, the modified formula could evaluate the onset behavior of vortex cavitation successfully also in quantitative aspects.