Abstract
This paper describes the issues of the high performance time-of-flight ultrasonic flow meter applied to the reactor feedwater measurement system of nuclear power plants. The reactor thermal power is determined by a calorimetric heat balance calculation based on several parameters obtained from specific plant instrumentations. The uncertainty of the reactor feedwater flow is the largest item on the thermal power uncertainty budget. From the nature of the non-intrusive measurement of the ultrasonic flow meters, significant improvement for high accuracy and durable feedwater measurement will be expected.
