Document: NUREG-0800
Document ID: 92d817ac-3ce3-4cf7-8d1a-627e8242fbf2
Document Type: srp
Title: PLANT DESIGN FOR PROTECTION AGAINST POSTULATED PIPING FAILURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070312.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.6.1
CFR Part: 
CFR Title: 

Content:
eak locations in the piping systems should be equivalent to the following: (a) ASME Section III Code Class I piping breaks should be postulated to occur at b the following locations in each piping run exceeds 2.0 S derived from the piping m fatigue analysis and based on all normal, upset, and testing plant conditions exceeds 0.1; and (4) At intermediate locations in addition to those determined by (1) and (2) above, selected on a reasonable basis as necessary to provide protection. As a minimum, there should be two intermediate locations for each piping run or branch run. (b) ASME Section III Code Class 2 and 3 piping breaks should be postulated to occur at the following locations in each piping run or branch run: (1) The terminal ends; (2) Any intermediate locations between terminal ends where either the circumferential or longitudinal stresses derived on an elastically calculated basis under the loadings associated with seismic events and operational plant conditions exceed 0.8 (S + S or the expansion stresses exceed 0.8 h A g h S ; and A (3) Intermediate locations in addition to these determined by (2) above, selected on a reasonable basis as necessary to provide protection. As a minimum, there should be two intermediate locations for each piping run or branch run. 3. The criteria used to determine the pipe break orientation at the break locations as specified under (2) above should be equivalent to the following: (a) Longitudinal breaks in piping runs and branch runs, 10 cm (4 inches) nominal i 42 pipe size and larger, and/or (b) Circumferential breaks in piping runs and branch runs exceeding 2.5 cm j (1 inch) nominal pipe size. 43 3.6.1-21 DRAFT Rev. 3 - April 1996 4. A summary should be provided of the dynamic analyses applicable to the design of Category I piping and associated supports which determine the resulting loadings as a result of a postulated pipe break, including: (a) The locations and number of design basis breaks on which the dynamic analyses are