Document: NRC Regulatory Guide
Document ID: 2e29f931-cdf2-4faa-a9e4-5d7cb237e57f
Document Type: regulatory_guide
Title: Service Limits and Loading Combinations for Class 1 Plate-and-Shell-Type Component Supports + HISTORY – HISTORY 10/2006 – DG-1169 , Proposed Revision 2
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063000484.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.130
CFR Part: 
CFR Title: 

Content:
ised even when using the plastic-analysis method in the methodology combination approved in Appendix F. This is especially important for identifying buckling or instability problems when the change of geometry should be considered to avoid erroneous results. Function of the Supported System In selecting the level of service limits for different loading combinations, the designer should take into account the function of the supported system. To ensure that systems whose normal function is to prevent or mitigate the consequences of events associated with an emergency or faulted plant condition [e.g., the function of the emergency core cooling system (ECCS) during faulted plant conditions] will operate properly regardless of plant condition, the use of ASME Code Section III Level A or B service limits of Subsection NF (or other justifiable limits provided by the Code) is appropriate. Deformation Limits Because component supports are deformation-sensitive load-bearing elements, satisfying the service limits of Section III will not automatically ensure their proper function. If stated in the ASME Code design specification, deformation limits may be the controlling criterion. However, if a particular plant condition does not require the function of a component support, the stresses or loads resulting from the loading combinations under the particular plant condition do not need to satisfy the design limits for the plant condition. Definitions Design Condition. The loading condition defined by NF-3112 of Section III of the ASME Boiler and Pressure Vessel Code. Operating Condition Categories. Categories of design limits for component supports defined by NF-3113 of Section III of the ASME Code. Plant Conditions. Operating conditions of the plant categorized as normal, upset, emergency, and faulted plant conditions. Normal Plant Conditions. Those operating conditions that occur in the course of system startup, operation, hot standby, refueling, and shutdown, with the