METHOD FOR MEASURING REACTIVITY OF CORE TO INSPECT VALIDITY

摘要

PURPOSE: To shorten the test interval for determining the value of control rod by measuring the reactivity of core using a plurality of neutron detectors and making a judgement that the measurement is valid when the measurement from respective detectors substantially match with each other, thereby permitting movement of a control rod. CONSTITUTION: A plurality of neutron detectors 20 detect a neutron flux generated in a core and delivers signals to a reactivity computer 24 through a signal regulator 22. The computer 24 averages samples sampled by respective detectors 20 over an interval of about 10mS and determines the reactivity at every different region in the core. Subsequently, the computer 24 solves a point motion equation and displays the instantaneous reactivity on a display 26. When the measured reactivity is significant statistically for a specified interval, a decision is made that the measurement is valid and the control rod is shifted to next step. According to the arrangement, test interval for determining the value of control rod can be shortened.