As a way of demonstrating the procedure given above, the results for the 14-inch Surge Line elbow are reproduced in this section. Two situations are considered, the elbow and the adjacent weld. The transients were based on data supplied and are reproduced in Attachment G.1

G. 4.1 Probability of Failure Surge Line Elbow — Base Case

This is a failure from base material and so the analysis assumed a fatigue based crack initiation followed by crack growth to failure. As stated earlier, the crack initiation and crack growth are assumed to be positively correlated. This assumption assumes that if the properties of the base material are such as to lead to an early crack initiation, it is very possible that these same properties

could result in a subsequently fast crack growth rate. The results of this analysis are shown in the following table:

Table G.2 Results for PWR Surge Line Elbow Base Case Analysis

RR-PRODIGAL gave the critical through wall defect length, based on the R6 criterion, as 14 inches.