Experimental investigation on transfer characteristics of temperature fluctuation from liquid sodium to wall in parallel triple-jet

A quantitative evaluation on thermal striping, in which temperature fluctuation due to convective mixing causes thermal fatigue in structural components, is of importance for integrity of nuclear reactors and also general plants. Sodium cooled fast reactor had also several incidents of coolant leakage due to the high cycle thermal fatigue. A sodium experiment of parallel triple-jet configuration was performed to evaluate transfer characteristics of temperature fluctuation from fluid to structure. The non-stationary heat transfer characteristics could be represented by a heat transfer coefficient, which was constant in time and independent of the frequency of temperature fluctuation.