Study of CAP1400 secondary pipe wall thinning rate under flow accelerated corrosion

Abstract

Wall thinning rate is an important issue during design of CAP1400 nuclear power plant (NPP) secondary loop. A single-phase flow accelerated corrosion (FAC) test loop was established to simulate the typical working condition of the secondary loop. The wall thinning rate of A335P11 and 20# steel elbow was measured using high precision ultrasonic sensor on the test loop. The results show that elbow part has higher thinning rate than that at straight part, especially at intrados of elbow. Wall thinning rate of 20# steel elbow is about three to four times of that A335P11 steel because of the high contents of Chromium at A335P11. According to the FAC test results it shows that A335P11 could be one of the preferred pipe material of CAP1400 secondary loop.