Experimental investigation on self-leveling behavior in debris bed

Cheng, S.*; Tanaka, Yohei*; Gondai, Yoji*; Kai, Takayuki*; Zhang, B.*; Matsumoto, Tatsuya*; Morita, Koji*; Fukuda, Kenji*; Yamano, Hidemasa   ; Suzuki, Toru; Tobita, Yoshiharu

Studies on the self-leveling behavior of debris bed are crucial for the assessment of core-disruptive accident (CDA) in sodium-cooled fast reactors (SFR). In this study, to clarify the behavior, experiments were performed by injecting nitrogen gas uniformly to particle beds. By this way relatively larger gas velocity might be achieved easily. Current experiments were conducted in a rectangular tank, where solid particles and water simulate the fuel debris and coolant. Based on the experimental observations and data obtained, with the help of dimensional analysis technique an empirical model was developed to predict the relative change of inclination angle () during self-leveling process. The calculated values of using proposed models and the experimental data were compared. Calculated values by the model agreed with the experimental values. The rationality of the proposed model was also confirmed by a detailed analysis of the effect of current experimental parameters.