Document: NUREG-0800
Document ID: e89cc26c-d19a-42b8-818a-fb598c05ccee
Document Type: srp
Title: PLANT DESIGN FOR PROTECTION AGAINST POSTULATED PIPING FAILURES IN FLUID
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340548.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.1
CFR Part: 
CFR Title: 

Content:
ystems that are located in the same areas as high-energy fluid systems which, by the criteria of A.1 to A.3 have postulated pipe break locations, through-wall leakage cracks need not be postulated. 3. For piping systems that are located in areas containing systems and components important to safety, but where no high-energy fluid systems are present, through-wall leakage cracks should be postulated at the most adverse location to determine the protection needed to withstand the effects of the resulting water spray and flooding. C. Side and Types of Pipe Breaks and Cracks 1. The following types of breaks should be postulated at the locations specified by the criteria listed under A. High-Energy Fluid Systems: a. longitudinal breaks in piping runs and branch runs with nominal pipe sizes of 4 inches and larger, b. circumferential breaks in piping runs and branch runs exceeding a nominal pipe size of 1 inch. 2. The following leakage cracks are postulated at the locations specified by the criteria listed under B. Moderate-Energy Fluid Systems: a. through-wall leakage cracks in piping and branch runs exceeding a nominal pipe size of 1 inch, where the crack opening is assumed as 1/2 the pipe diameter in length and 1/2 the pipe wall thickness in width. 3.6.1-26 Rev. 2 - October 1990 FOOTNOTES 'High-energy systems include those systems where either of the following conditions are met: a) the maximum operating temperature exceeds 2000F, and b) the maximum operating pressure exceeds 275 psig. 2Moderate energy systems include those systems where both of the following conditions are met: a) the maximum operating temperature is 200'F or less, and b) the maximum operating pressure is 275 psig or less. 'Structures, systems, and components important to safety, as specified herein refer to those plant features required to shut down the reactor safely and maintain the plant in the cold shutdown condition. 4Break in piping means (a) a complete circumferential pipe severance and, (b) a