Document: NRC Regulatory Guide
Document ID: 70415715-297f-4d60-841c-514b0372a131
Document Type: regulatory_guide
Title: 02/2017 (Rev. 5)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1608/ML16082A501.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.26
CFR Part: 
CFR Title: 

Content:
an be isolated from the reactor coolant system by two valves in series (with automatic closure of open valves). While 10 CFR 50.55a does not explicitly refer to Quality Group A, it has been defined as such since the initial revision of this regulatory guide. Because this scope is well-defined, no further guidance is presented in this regulatory guide for Quality Group A. 2. Quality Group B The Quality Group B standards given in Table 1 on page 7 of this guide should be applied to water- and steam-containing pressure vessels, heat exchangers (other than turbines and condensers), storage tanks, piping, pumps, and valves that are either (1) part of the reactor coolant pressure boundary, as defined in 10 CFR 50.2, “Definitions,” but excluded from the requirements of 10 CFR 50.55a(c)(1) for reactor coolant pressure boundary components pursuant to paragraph (c)(2) of that section (as mentioned above in the section on Quality Group A), or (2) not part of the reactor coolant pressure boundary but part of the following: (a) systems or portions of systems2 important to safety that are designed for (i) emergency core cooling, (ii) post-accident containment heat removal, or (iii) post-accident fission product removal; (b) systems or portions of systems important to safety that are designed for (i) reactor shutdown or (ii) residual heat removal; (c) those portions of the steam systems of boiling-water reactors extending from the outermost containment isolation valve up to but not including the turbine stop and bypass valves,3 and connected piping up to and including the first valve that is either normally closed or capable of automatic closure during all modes of normal reactor operation; alternatively, for boiling-water reactors containing a shutoff valve (in addition to the two containment isolation valves) in the main steamline and the main feedwater line, those portions of the steam and feedwater systems extending from the outermost containment isolation valves up to and