MULTIPLE SURFACE COIL EDDY-CURRENT PROBING DEVICE FOR DETECTING RADIALLY DIRECTIONED CRACKS ON A COVERING PIPE OF A CONTROL ROD IN A LIGHT WATER REACTOR-TYPE NUCLEAR REACTOR

摘要

PURPOSE: A coil eddy-current probing device is provided to prevent an accident such as a shutdown of the operation of a nuclear power plant due to a failure of a control rod assembly during the operation of the nuclear reactor by detecting radially directioned cracks and evaluating the safety of a covering pipe of a control rod. CONSTITUTION: A coil eddy-current probing device comprises: plural probes(100) arranged in a radial direction of a covering pipe of a control rod; and ferrite cores(140) inserted in surface coils(130) mounted in the plural probes(100) and for increasing a permeability to enhance sensitivity to minute cracks, wherein the surface coils(130) is connected to a circuit and the circuit compensates a difference of electrical characteristics occurring during manufacturing the coils(130),