Measuring device for coolant recycling flow rate in nuclear reactor

Purpose: To measure the recycling flow rate at high accuracy in a case where all or a part of coolant recycling pumps are in operation. Constitution: There are disposed a plurality of first pump section calculators for calculating the flow rates of coolant recycling pumps based on the outputs from differential pressure gage and speed meter, as well as second pump section calculators for calculating the backflow flow rate from the output of the differential pressure gas if fluid flow in the backward direction should occur. There is also provided a calculator for calculating the total sum of the flow rate in the forward direction based on the output signals from a plurality sets of first and second pump section calculators. By calculating the recycling flow rate in the forward direction during pump operation by the first calculators, while calculating the flow rate backwarding during stopping of the pump operation by the second calculator, accurate recycling flow rate is determined as the mathematical sum for both of the calculated values. Since the relationship between the differential pressure and the flow rate obtained directly by a plant test, etc. can be utilized, the measurement accuracy can be improved only with limited errors. (Kamimura, M.)