Results of the application of acoustic emission during hydrotests of primary circuit components of nuclear reactors

The examinations so far carried out on reactor components during Hydrotest have shown that: The examination technique for AE for vessel testing has been developed today to such an extent that within certain limits the background noise can be isolated from genuine flaw indications with no significant reduction in measuring sensitivity. Investigations of the wave propagation of test signals of burst type show that signals transmitted from outside and inside can be located with approximately the same degree of sensitivity and accuracy. AE is a very sensitive method of non-destructive examination, able to detect even very small flaws. The AE-sources lie for the most part in areas of seam welds, nozzles, welded on attachments, closure studs or other prominent areas. Indications which were found by AE need not necessarily be detectable by the ultrasonic method. Complete concurrence of ultrasonic and AE-indications cannot be expected for smaller flaws on account of the completely different physical bases of both methods. Other methods of non-destructive Examination can make the acoustic emission indications visible under some circumstances, as the example above shows. For larger cracks this is not true. Small leaks can be identified in a short time and can be located within certain limits. (orig./RW)