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:
aks specified in 3(i): (1) Longitudinal breaks in fluid system piping and branch runs should be postulated in nominal pipe sizes 4-inch and larger, except where the maximum stress range 14 exceeds the limits specified in 2.A(iii)(1) and 2.A(iii)(2), and the axial stress range is at least 1.5 times the circumferential stress range. (2) Longitudinal breaks need not be postulated at terminal ends. (3) Longitudinal breaks should be assumed to result in an axial split without pipe severance. Splits should be oriented (but not concurrently) at two diametrically opposed points on the piping circumference such that the jet reactions cause out-of-plant bending of the piping configuration. Alternatively, a single split may be assumed at the section of highest 14 See Footnote 2. BTP 3-4-10 Revision 3 –December 2016 tensile stress as determined by detailed stress analysis (e.g., finite element analysis). (4) The dynamic force of the fluid jet discharge should be based on a circular or elliptical (2D x 1/2D) break area equal to the effective cross-sectional flow area of the pipe at the break location and on a calculated fluid pressure modified by an analytically or experimentally determined thrust coefficient as determined for a circumferential break at the same location. Line restrictions, flow limiters, positive pump-controlled flow, and the absence of energy reservoirs may be taken into account, as applicable, in the reduction of jet discharge. (5) Piping movement should be assumed to occur in the direction of the jet reaction unless limited by structural members, piping restraints, or piping stiffness as demonstrated by inelastic limit analysis. (iii) Leakage Cracks Leakage cracks should be postulated at those axial locations specified in 2.A(v) for high-energy fluid system piping and in those piping systems not excluded in 2.B(iii)(1) for moderate-energy fluid system piping. (1) Leakage cracks need not be postulated in 1-inch and smaller piping. (2) For high-energy fluid