Document: NUREG-0800
Document ID: 5c84a1c2-9405-4849-8c5f-415a0bb66a22
Document Type: srp
Title: in connection with reactor internals.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070337.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.5
CFR Part: 
CFR Title: 

Content:
ture oscillations as well as other typical piping stresses, including piping that may be rendered susceptible to these conditions through leaking valves, should be identified and designed to withstand combined stresses caused by various loads and the worst temporal and spatial distributions of temperature to be encountered in service. NRC Bulletin 88-08 (Reference 12) specifies acceptable actions in this regard. NRC Bulletin 88-11 (Reference 13) specifies acceptable actions to address thermally stratified flow and/or thermal striping in PWR pressurizer surge lines.138 Piping subject to stresses from temperature stratification or temperature oscillations, including piping that may be rendered susceptible to these conditions through leaking valves, should be explicitly identified and designed to account for these stresses.139 Fatigue evaluations are required by the Code for all Class 1 components. Fatigue evaluations should also be completed for all ASME Class 2 and 3 components and component supports, and core support structures that are subject to thermal cyclic effects or dynamic cyclic loads. The scope, methods, and results of fatigue evaluations should be reviewed by the staff. Fatigue analyses of components and supports should be completed if the fatigue evaluations so indicate and these analyses, as well as their results, should be reviewed and compared with the guidance in the Code. Fatigue evaluations and subsequent analyses (if required) of components and supports should be based on the design life of the plant. Environmental conditions which could have cumulative effects that could adversely affect the design margins that are built into the ASME fatigue design curves should also be considered.140 1.2 Service Loading Combinations The identification of individual loads and the appropriate combination of these loads (i.e., sustained loads, loads due to system operating transients (SOT) , 141 OBE, SSE, LOCA, DBPB, MS/FWPB and their dynamic effects)