Development of Eddy Current Testing System for Bottom-Mounted Instrumentation Nozzle in Reactor Pressure Vessel
小林 徳康 Noriyasu KOBAYASHI 上野 聡一 Souichi UENO 千田 格 Itaru CHIDA 落合 誠 Makoto OCHIAI 藤田 友基 Tomoki FUJITA 市川 博也 Hiroya ICHIKAWA
Bottom-mounted instrumentation BWR Eddy current testing PWR Stress corrosion cracking
We confirmed the defect detection performance of the eddy current testing (ECT) system in order to inspect the bottom-mounted instrumentation (BMI) nozzle in reactor pressure vessel. We developed the small size cross coil type ECT sensor that has the magnetic cores near the coils and the sensor scanning equipment based on the portable laser peening system. According to the experimental results that measured the sensitivity for the defects on the concave specimen and the relationship between the sensor inclined angle and the defect detecting sensitivity on the convex specimen, the sensor has the adequate sensitivity and the decrease of sensitivity depend on the sensor inclined angle reduced. From the artificial stress corrosion cracking detection test using the developed ECT system, we confirmed that the ECT system has the potential for detecting the defect on the little space. These experimental results indicated that there is the possibility that we can inspect the BMI nozzle.