Document: NUREG-0800
Document ID: c6f58bab-ddce-42eb-a3ef-02dd3da952fc
Document Type: srp
Title: Revision 3 – December 2016
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1608/ML16085A315.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3
CFR Part: 
CFR Title: 

Content:
iping located in an area in which a break in high-energy fluid system piping is postulated, provided such leakage cracks would not result in more limiting environmental conditions than the high-energy piping break. Where a postulated leakage crack in the moderate-energy fluid system piping results in more limiting environmental conditions than the break in proximate high-energy fluid system piping, the provisions of 2.B(iii) should be applied. (v) Fluid Systems Qualifying as High-Energy or Moderate-Energy Systems. Through-wall leakage cracks instead of breaks may be postulated in the piping of those fluid systems 12 that qualify as high-energy fluid systems for only a short operational period but qualify as moderate-energy fluid systems for the major operational period. 3. Type of Breaks and Leakage Cracks in Fluid System Piping (i) Circumferential Pipe Breaks The following circumferential breaks should be postulated individually in high- energy fluid system piping at the locations specified in 2.A of this BTP: (1) Circumferential breaks should be postulated in fluid system piping and branch runs exceeding a nominal pipe size of 1 inch, except where the maximum stress range 13 exceeds the limits specified in 2.A(iii)(1) and 10 See Footnote 2. 11 See Footnote 2. 12 The operational period is considered “short” if the fraction of time that the system operates within the pressure-temperature conditions specified for high-energy fluid systems is about 2 percent of the time that the system operates as a moderate-energy fluid system (e.g., systems such as the reactor decay heat removal system qualify as moderate-energy fluid systems; however, systems such as auxiliary feedwater systems operated during pressurized-water reactor (PWR) reactor startup, hot standby, or shutdown qualify as high-energy fluid systems). 13 See Footnote 2. BTP 3-4-9 Revision 3 –December 2016 2A(iii)(2), and the circumferential stress range is at least 1.5 times the axial stress range.