Document: NUREG-0800
Document ID: 22884f18-189e-46a8-81b2-45db11edf145
Document Type: srp
Title: SYSTEM QUALITY GROUP CLASSIFICATION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1422/ML14227A641.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.2.2
CFR Part: 
CFR Title: 

Content:
d schematics or P&IDs, if applicable, may be reviewed to ensure that the applicant has delineated in detail the system quality group classification boundaries for systems important to safety. ASME BPV Code class and/or quality group is generally shown in Tier 2. If during the review of Tier 1 information according to SRP Section 14.3, discrepancies are identified between Tier 1 and Tier 2 system description and schematics or P&IDs concerning quality group or ASME BPV Code class, the applicant should be requested to verify consistency between the Tier 1 and Tier 2 information. 4. “Class breaks”—that is, the boundary between classifications such as Quality Group B and Quality Group C within a system—should be located downstream of a valve that is either normally closed or capable of automatic closure when the safety function is required. This valve should be assigned the higher classification. Any change in quality group classification with no valve present is considered acceptable only when it can be demonstrated that the safety function of the system is not impaired by a failure on the lower-classification side of the boundary. Further guidance on this topic is provided in RG 1.26. 5. The following fluid systems are examples of those that are reviewed by the staff with regard to quality group classification. Typical system names are provided below, based on historical staff reviews of prior applications. It should be noted that systems whose function is equivalent to those described in RG 1.26 may not be identified by these names, but the staff should consider the systems and functions in a given application for consistency with these general principles when evaluating whether the classifications are appropriate. Pressurized-Water Reactor Fluid Systems Subject to Quality Group Classification • auxiliary feedwater system • boron thermal regeneration system1, 2 • boron recycle system1, 2 • chemical and volume control system • combustible gas control