Experimental investigation of thermal stratification in a pressurizer surge line

Thermal stratified flow in a pressurizer surge line was investigated on a 1/3 scaled model based on the Richardson number similarity. A database which could be used to verify the thermal stratification simulation was established. Temperature distributions inside and on the outer surface of a surge line pipe with different surge line inlet flow rates were monitored and compared. Thermal stratification occupied a large part of the surge line. Temperature differences at all the measured test sections reached half of the maximum inlet temperature difference. As the surge line inlet velocity increased, the pattern of temperature distribution showed a similar trend and the cross-section maximum temperature difference changed little. This was consistent with the existence of thermal stratification at operating conditions in the corresponding pressurized water reactor.