Document: NRC Regulatory Guide
Document ID: 7da9830f-b2a1-484a-82ce-5b0a588c4fce
Document Type: regulatory_guide
Title: Protection Against Pipe Whip Inside Containment
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1229/ML12298A123.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.46
CFR Part: 
CFR Title: 

Content:
r operation, upset conditions (e.g., anticipated operational occurrences), and testing conditions. "Sm is the design stress intensity as specified in Section III of the ASME Boiler and Pressure Vessel Code. 7U is the cumulative usage factor as specified in Section III of the ASME Boiler and Pressure Vessel Code. S A reaýsonable basis for locating intermediate piping breaks should 'consider such factors as (1) points of maximum stress intensity and/or cumulative usage factors (excluding terminal ends) in the piping run or branch run, (2) length of the piping run or branch run over which no protective measures against pipe whipping are provided, and (3) changes in coordinate plane (i.e., X-Y,Y-Z, and X-Z) of the piping run or branch run as determined by tracing the run in both directions starting at each terminal end. SSh and SA are stresses calculated by the-rules of NC-3600 and ND-3600 for Class 2 and 3 components, respectively, of the ASME Code Section III Winter 1972 Addenda. 1.46-3 -4 a. Longitudinal1" breaks in piping runs and branch runs 4 inches nominal pipe size and larger; b. Circumferential1 breaks in piping runs and branch runs exceeding 1 inch nominal pipe size. 4. Measures for restraint against pipe whipping as a result of the design basis breaks postulated to occur at the locations specified under regulatory positions 1 and 2 above need not be provided for piping where any one of the following applies: a. The piping is physically separated (or isolated) from other piping or components by protective barriers or is. restrained from whipping by plant design features such as concrete encasement; "Longitudinal breaks are parallel to the pipe axis and oriented at any point around the pipe circumference. The break area is equal to the sum of the effective cross-sectional flow area upstream of the break location and downstream of the break location or is equal to a break area determined, by test data which defines the break geometry. Dynamic forces resulting