Study on Thermal Striping Phenomena in Fast Reactors : Transfer Characteristics of Temperature Fluctuation to Structure

Abstract

A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing causes thermal fatigue in structural components, is of importance for reactor safety. It is necessary for understanding of thermal striping phenomena to evaluate transfer of temperature fluctuation from fluid to structures. Decrease of fluctuation amplitude is expected in the process of heat transfer from fluid to structure. In this study, a sodium experiment of parallel triple jets configuration was performed in order to evaluate transfer characteristics of temperature fluctuation from fluid to structure. As for the experimental geometry, a cold jet on the center and two hot jets on both sides flowed vertically and along the wall. As the results, it was shown that the non-stationary heat transfer characteristics could be represented by a heat transfer coefficient, which was constant in time. The heat transfer coefficients were correlated to the 0.8 power of Peclet number.