DETECTION OF DEFECTS IN CONTROL RODS BY EDDY CURRENT EXAMINATION

摘要

To detect the defects of control rods in a reactor, a standard specimen including external defects, internal defects, and through-hole defects is fabricated. The eddy current signals of these defects are stored, analyzed on a PC by a program developed to acquire data of eddy currents. The optimum frequency for detecting defects of the control rods is 200kHz. The defect location, and defect shape of the cladding in the control rods are detected by analyzing the impedance phase of the eddy current. It is confirmed that the defects in hafnium of control rods can be detected.