METHOD FOR MEASURING THICKNESS OF CLAD LAYER OF NEUTRON ABSORBING ROD OF ZIRCALOY CLAD HAFNIUM

摘要

PURPOSE:To measure the titled thickness accurately by nondestructive inspection by utilizing the phase difference caused from the difference in resistance ratio among the factors having influences on the impedance of a coil by eddy current. CONSTITUTION:50kHz-5MHz high frequency is impressed to the probe testing coil 15 attached to the top end of an eddy current flow detector 14, and the AC phase obtained from the coil 15 is detected. A neutron absorbing rod 16 in which the surface of the main body 16a consisting of hafnium is covered with a zircaloy clad layer 16b is supported on a revolving base frame 17, and the horizontal movement and revolving motion are performed continuously and intermittently.