Document: NUREG-0800
Document ID: ba447c99-c09a-4d8c-84cd-804a2261f17c
Document Type: srp
Title: MAINTENANCE RULE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0729/ML072920088.pdf
Revision Date: 2023-06
Chapter: 17
Section ID: 17.6
CFR Part: 
CFR Title: 

Content:
ful accomplishment of a mitigation function (as may be determined through risk-informed methods) and (3) those whose use is implied and that are essential to the | performance of one or more EOP steps and for which there are no | reliable and consistently readily available (under EOP conditions) | alternatives. SSCs that do not provide or support a mitigating function, | but are included in the EOPs for other reasons, e.g operator convenience | or simplifying EOP compliance, event recovery, equipment protection, | etc., are not required to be in the MR scope under 50.65(b)(2)(i); nor are | SSCs used in the Severe Accident Mitigation Guidelines (SAMGs). Note | that as used in this context, the word “recovery” refers to long-term or | supplementary recovery actions to restore normal plant conditions; not | immediate recovery actions to put the plant in a safe, stable condition.” | | If the amplified and clarified definition is in effect at the time of the COL | application, the applicant should describe the process for identifying | SSCs explicitly mentioned in the EOPs (including those mentioned in referenced procedures), but that are proposed not to be included in the MR scope. The process for exclusion from scope should address the bases for exclusion from scope (e.g., not used for accident or transient | mitigation), the bases for inclusion in the EOPs (e.g., operator | convenience, equipment protection), the portion of any and all mitigating | functions provided, the expectation of reliability in EOP application(s), and | the means by which operators are alerted (e.g., procedural warnings, cautions, disclaimers, signs, etc.) to reduced assurance or expectation of reliability. (iii) SSCs whose failure could prevent safety-related SSCs from fulfilling their | safety-related functions in accordance with 50.65(b)(2)(ii). The applicant | should describe how the process considers system interdependencies, | including failure modes and effects of nonsafety-related