Document: NUREG-0800
Document ID: 2ab6f47e-1578-451d-b6ad-29434e31a72b
Document Type: srp
Title: SYSTEM QUALITY GROUP CLASSIFICATION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340619.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.2.2
CFR Part: 
CFR Title: 

Content:
s that are less important to safety. An applicant may use the NRC Group Classification system identified in Regulatory Guide 1.26 or, alternately, the corresponding ANS classification system of Safety Classes which can be cross-referenced with the classification groups in Regulatory Guide 1.26. There are also systems of light-water-cooled reactors important to safety that are not identified in Regulatory Guide 1.26 and which the staff considers should be classified Quality Group C. Examples of these systems 3.2.2-2 Rev. 1 - July 1981 are: diesel fuel oil storage and transfer system; diesel engine cooling water system, diesel engine lubrication system, diesel engine starting system, diesel engine combustion air intake and exhaust system, and instrument and service air systems required to perform a safety function; and certain ventilation plant systems. Gas treatment systems which are considered as engineered safeguards systems should be classified Quality Group B. The information supplied in the application identifying fluid systems important to safety is reviewed for completeness, and the quality group classification, ASME Code and code class, and quality assurance requirements of each individual major component are checked for compliance with the above criteria. The various modes of system operation are checked to assure that the assigned NRC quality groups are acceptable. The piping and instrumentation diagrams are reviewed to assure that the applicant has delineated in detail the system quality group classification boundaries for systems important to safety. Each individual line on a diagram Is checked to assure the accuracy of the assigned quality group classification, including branch lines such as vent lines, drain lines, fill lines, test lines, and sample lines. Changes in quality group classification are permitted normally only at valve locations, with the valve assigned the higher clas- sification. A change in quality group classification with no valve