Document: NRC Regulatory Guide
Document ID: 96ecfd93-e64a-4f35-93fe-d3b95daac61d
Document Type: regulatory_guide
Title: Monitoring the Effectiveness of Maintenance at Nuclear Power Plants + HISTORY –HISTORY 06/2018 – DG-1336 , Proposed Revision 4 09/2011 – DG-1278 , Proposed Revision 3 08/1996 – DG-1051 , Proposed Revision 2 06/1994 – DG-1031, Proposed Revision 1 11/1992 – DG-1020, Proposed Revision 0 (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1812/ML18129A080.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.160
CFR Part: 
CFR Title: 

Content:
t in the EOP. For example, all SSCs associated with an instrument loop supporting a control room instrument that is specifically called out in the EOP are considered explicitly used. Implied use means those SSCs not specifically called out in the EOP, but are understood to be essential for successful completion of the associated mitigating EOP step, although they may not directly address or mitigate the event. NUMARC 93-01 also discusses how “[w]hen the EOPs direct the user to another procedure, the associated SSCs required to perform the EOP mitigating function are included in the scope of the Maintenance Rule.” Further, “SSCs whose use is implied and is necessary to perform the EOP steps in the necessary response times, such as emergency lighting or communication SSCs, are included in the scope of the Maintenance Rule.” These descriptions of “use” inform how the terms may be applied to FSGs. Fundamentally, the EOPs address design basis accidents, whereas the FSGs are “guidance and strategies to maintain or restore core cooling, containment and spent fuel pool (SFP) cooling capabilities following a beyond- design-basis external event,” as described in EA 12-049, Because the FSG equipment is not essential to the EOPs, it’s not considered to be used by the EOPs; the EOPs can be carried out even if no FSG equipment is available. Reflecting this concept, section 8.2.1.3 of Rev. 4F of NUMARC 93-01 adds the following: o When steps are added to an EOP only to direct to FSGs for implementing non-safety related SSCs, those SSCs should not be considered used in the EOP, as long as the changes associated with these steps made to the EOP do not impede the successful implementation of other SSCs used in the EOP. An appropriate technical basis should be documented that demonstrates that these changes do not impede the successful implementation of the other SSCs. These uses of non-safety-related SSCs should be evaluated against all other 10 CFR 50.65(b) scoping