Document: NUREG-0800
Document ID: 0e333e1a-276a-43f1-b2ab-fdf1009c6f92
Document Type: srp
Title: Draft Revision 3 – August 2015
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1422/ML14227A646.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3
CFR Part: 
CFR Title: 

Content:
ew (as-built) intermediate break locations are not mitigated by the original pipe-whip restraints and jet shields. (ii) A change is necessary in pipe parameters such as major differences in pipe size, wall thickness, and routing. (2) With the exceptions of those portions of piping identified in 2A(ii), breaks in Class 2 and 3 piping (ASME Code, Section III) should be postulated at the following locations in those portions of each piping and branch run: (a) At terminal ends. (b) At intermediate locations selected by one of the following criteria: (i) At each pipe fitting (e.g., elbow, tee, cross, flange, and nonstandard fitting), welded attachment, and valve. Or, where the piping contains no fittings, welded attachments, or valves, at one location at each extreme of the piping run adjacent to the protective structure. (ii) At each location where stresses are calculated5 by the sum of Eqs. (9) and (10) in NC/ND-3653 of ASME Code, Section III, to exceed 0.8 times the sum of the stress limits given in NC/ND-3653. As a result of piping reanalysis, due to differences between the design configuration and the as-built configuration, the highest stress locations may be shifted; however, the 3 This term is defined as the extremities of piping runs that connect to structures, components (e.g., vessels, pumps, valves), or pipe anchors that act as rigid constraints to piping motion and thermal expansion. A branch connection to a main piping run is a terminal end of the branch run, except where the branch run is classified as part of a main run in the stress analysis and is shown to have a significant effect on the main run behavior. In piping runs that are maintained pressurized during normal plant conditions for only a portion of the run (i.e., up to the first normally closed valve), a terminal end of such a run is the piping connection to this closed valve. 4 See Footnote 2. 5 See Footnote 2. BTP 3-4-6 Draft Revision 3 – August 2015 initially determined intermediate break