Document: NUREG-0800
Document ID: 7bd74f6c-471d-40b1-9659-6a5e00c5f169
Document Type: srp
Title: MAINTENANCE RULE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1409/ML14099A044.pdf
Revision Date: 2023-06
Chapter: 17
Section ID: 17.6
CFR Part: 
CFR Title: 

Content:
afety function; or iii. Nonsafety-related SSCs whose failure could cause a reactor scram or actuation of a safety-related system. Related to Item 1.B.i, nonsafety-related SSCs that are necessary to be in the MR scope are those explicitly used in the EOPs that provide mitigating functions. Specifically: a. SSCs used in plant EOPs are required for mitigation of the event/symptom that necessitated entry into the EOP. b. SSCs used in plant EOPs are required for mitigation of the event/symptom that necessitated entry into the EOP. 17.6-5 Revision 2 – July 2014 c. Only those SSCs under licensee control need be included in the MR scope. Note: Severe Accident Management Guidelines (SAMGs) are not considered to be EOPs. Equipment described only in SAMGs would not be in scope of the MR unless otherwise required by 10 CFR 50.65(b). Equipment used in support of 10 CFR 50.54(hh)(2) (Loss of Large Areas) would not be in scope of the MR unless otherwise required by 10 CFR 50.65(b). When 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 MR. SSCs whose use are implied and are 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 MR. Since the MR is a performance-based regulation, licensees have the flexibility to add or remove SSCs from the scope of 10 CFR 50.65(b) if an adequate technical basis exists for including or excluding the SSCs in question. For clarity and universal understanding regarding these scoping criteria, the following definitions are offered: “Explicitly used” means those SSCs specifically called out in the EOP by tag identification or noun name that provide a mitigating function, and includes those SSCs required to support the explicitly used SSCs even though they are not called out in the EOP. For example, all SSCs associated with an instrument loop supporting a