Detection of subassembly bowing in a fast breeder reactor using glancing angle ultrasonic imaging

Mapping of subassembly (SA) heads using down viewing transducers mounted on an under sodium ultrasonic scanner can be used for detection and evaluation of SA bowing. However, due to constraints in the rotating plugs on which the scanner is mounted, the down viewing transducers may not reach on top of all the SAs. For such a scenario, an ultrasonic glancing angle based imaging methodology (GAIM) is developed in the present paper for assessment of SA bowing. The signatures in the ultrasonic signals that can be used for detection of SA head bowing (towards or away) with respect to the ultrasonic transducer are reported in this paper. In addition to the detection of the SA bowing, glancing angle images from two orientations are superimposed to get a better visualization of the honeycomb arrangement of SAs. Further, a method for quantitative estimation of the bowing is also presented. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A new ultrasonic imaging method is introduced in this paper for assessing the bowing of subassembly (SA) heads. Specific signatures in the ultrasonic signals can be used to detect the bowing of SA heads, and images from two orientations are superimposed for better visualization of the arrangement of SAs.