Method of discriminating through-wall cracks and measuring through-wall length of cracks in nuclear steam generator tubes using eddy current signals

摘要

Disclosed herein is a method of discriminating a through-wall crack and measuring the through-wall length of the crack in a steam generator tube of a nuclear power plant. The method of the present invention is characterized in that the through-wall crack is discriminated and the through-wall length of the crack is measured in such a way that there are measured the number and positions of inflection points of a graph that is plotted by relating characteristic amplitude values of eddy current signals, which are generated whenever a coil of a motorized rotating probe passes the crack while being spirally rotated, to the positions in the length of the crack.