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:
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. Instrument lines, as well as 1 inch and less nominal pipe or tubing size, should meet the provisions of Regulatory Guide (RG) 1.11, “Instrument Lines Penetrating Primary Reactor Containment (Safety Guide 11).” (2) Where break locations are selected without the benefit of stress calculations, breaks should be postulated at the piping welds to each fitting, valve, or welded attachment. (3) Circumferential breaks should be assumed to result in pipe severance and separation amounting to at least a one-diameter lateral displacement of the ruptured piping sections unless physically limited by piping restraints, structural members, or piping stiffness as may be demonstrated by inelastic limit analysis (e.g., a plastic hinge in the piping is not developed under loading). (4) The dynamic force of the jet discharge at the break location should be based on the effective cross-sectional flow area of the pipe and on a calculated fluid pressure as modified by an analytically or experimentally determined thrust coefficient. Limited pipe displacement at the break 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) Pipe whipping should be assumed to occur in the plane defined by the piping geometry and configuration and to initiate pipe movement in the direction of the jet reaction. (ii) Longitudinal Pipe Breaks The following longitudinal breaks should be postulated in high-energy fluid system piping at the locations of the circumferential breaks 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