Code Case N-513 provides evaluation rules and criteria for temporary acceptance of flaws, including through-wall flaws, in moderate energy piping. The application of the Code Case is restricted to Class 2 and 3 systems, so that safety issues regarding short-term system operation are minimized. The first version of the Code Case was published in 2000. Since then, there have been four revisions to the Code Case that have been published by ASME. The technical bases for the original version of the Code Case and the four revisions have been previously published.
There is currently work underway to employ the methods given in N-513 for a new and separate Code Case for higher pressure piping applications. This paper provides the technical basis for the proposed Code Case that includes a structural integrity evaluation and consideration of potential jet thrust forces. In addition, discussion is provided on additional Code Case requirements considering the application to higher pressure systems in order to bolster defense-in-depth. Note that the proposed Code Case still maintains the temperature limit given in N-513.
