Document: NUREG-0800
Document ID: 3d8f7691-e488-4083-af2f-eef689c0ec98
Document Type: srp
Title: ASME CODE CLASS 1, 2, AND 3 COMPONENTS AND COMPONENT SUPPORTS,
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0704/ML070430397.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.3
CFR Part: 
CFR Title: 

Content:
e appropriate subsections of the Code as required in 10 CFR 50.55a, including limitations on pressure, and including the requirements of this appendix. Component supports shall be designed to maintain deformations within appropriate limits as specified in the component support Design Specifications. Design loadings shall be established in the Design Specification. The design limits of the appropriate subsection of the Code shall not be exceeded for the design loadings specified. Fatigue evaluations are required by the Code for all Class 1 components. Fatigue evaluations should also be completed for all Code 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 associated analyses 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. To avoid fatigue failure during the life of the plant, unisolable sections of piping connected to the reactor coolant system that are subject to stresses from temperature stratification or temperature oscillations as well as other typical piping stresses, (including piping that may be rendered susceptible to these 3.9.3-20 Revision 2 - March 2007 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 specifies acceptable actions in this regard.