Coolant leakage detecting method for coolants

Purpose: To rapidly and surely detect the coolant leakages by determining the level fluctuation rate in the drain sump. Method: The drain sump level in the dry well floor is detected by a ultrasonic level detector and sent to a leakage rate calculating device as a level signal. While on the other hand, a signal indicating the running state of the drain sump pump for the dry well is inputted to a scheduler. The coolant leaking rate calculated in the leaking rate calculator is sent as a signal to a comparator. The comparator judges the state of the signal relative to a limit value and issues an output, depending on the comparison result, to an alarm output device. The alarm output device informs the presence or absence of the coolant leakages. (Seki, T.)