Document: NUREG-0800
Document ID: 81538e9c-cf5c-48b9-be32-fc15df183666
Document Type: srp
Title: -21
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1404/ML14043A231.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.3
CFR Part: 
CFR Title: 

Content:
Revision 3 – April 2014 be encountered in service. NRC Bulletin 88-08 specifies acceptable actions in this regard. NRC Bulletin 88-11 specifies acceptable actions to address thermally stratified flow and/or thermal striping in PWR pressurizer surge lines. 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. Fatigue design of Code Class 1, 2 and 3 piping is reviewed in SRP Section 3.12. B. 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), OBE, SSE, LOCA, design basis-pipe break (DBPB), main steam/feedwater pipe break (MS/FWPB) and their dynamic effects) should be in accordance with Section 1.3. The appropriate method of combination of these loads should be in accordance with NUREG-0484, "Methodology for Combining Dynamic Loads.” Exemptions that have been permitted from regulatory requirements to use OBE and the acceptable alternative to use of OBE in the design of components, component supports, and core support structures are described in Subsection III.1 of this SRP section. C. Service Conditions (i) Service Limit A. Code Class 1, 2, and 3 components, component supports, and core support structures shall meet a service limit not greater than Level A when subjected to sustained loads resulting from normal plant/system operation. (ii) Service Limit B. Code Class 1, 2, and 3 components, component supports, and core support structures shall meet a service limit not greater than Level B when subjected to the appropriate combination of loadings resulting from (1) sustained loads, (2) specified plant/SOT, and (3) the OBE. Exemptions that have been permitted from regulatory requirements to use OBE and the acceptable alternative to