Second Mechanized In-Service Inspection of EBR-2 Steam Generator

The second mechanized ultrasonic inspection of evaporation EV-702, part of the EBR-II steam-generator system, was completed in March 1978. The 2 1/2 Cr-1 Mo duplex tubes were inspected from the bore (water) side for flaws and changes in wall thickness and for evaluating the condition of the braze between the tubes. An addition to this second inspection was the use of an ultrasonic probe to search for circumferential flaws. The inspection equipment was thoroughly checked and routinely calibrated, using a reference standard containing electrical-discharge-machined notches. Notches as small as 1.6 mm long by 0.25 mm deep were readily detected.