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:
exceed 2 Sm6 for ferritic steel and.2.4 Sm for austenitic steel; c. Any intermediate locations between terminal ends where the cumulative usage factor U7 derived from the piping fatigue analysis under the loadings associated with specified seismic events and operatfonal plant conditions exceeds 0.1; d. At intermediate locations in addition to those determined by regulatory positions 1.b. and i.c. above, selected on a reasonable basis8 as necessary to provide protection. As a minimum, there should be two intermediate locations for each piping run or branch run. 2. ASME Section III Code Class 2 and 3 piping break-s should be postulated to occur at the following locations in each piping run or branch run: a. The terminal ends: b. Any intermediate locations between terminal ends where either the circumferential or longitudinal stresses derived on an elastically calculated basis under the loadings associated with specified seismic events and operational plant conditions exceed 0.8 (Sh + SA).9 c. If a fatigue analysis is performed, any intermediate locations between terminal ends where the cumulative usage factor U under the loadings associated with specified seismic events and operational plant conditions exceeds 0.1; d. Intermediate locations in addition to those determined by regulatory positions 2.b. and 2.c. above, selected on 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 following types of breaks should be postulated at the locations identified by regulatory positions 1 and 2 above: "Specified seismic events are earthquakes that produce at least 50 percent of the vibratory motion of the Safe Shutdown Earthquake. 5Operational plant conditions include normal reactor 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