Document: NUREG-0800
Document ID: ac3185c1-0851-4b4d-b3f5-31c884360119
Document Type: srp
Title: Setpoints
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1601/ML16019A088.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.2
CFR Part: 
CFR Title: 

Content:
t vulnerabilities to common- cause failures have adequately been addressed. (2) In performing the assessment, the vendor or applicant should analyze each postulated common-cause failure for each event that is evaluated in the accident analysis section of the SAR using best-estimate methods. The vendor or applicant should demonstrate adequate diversity within the design for each of these events. (3) If a postulated common-cause failure could disable a safety function, then a diverse means, with a documented basis that the diverse means is unlikely to be subject to the same common-cause failure, should be provided to perform either the same function or a different function. The diverse or different function may be performed by a non-safety system if the system is of sufficient quality to perform the necessary function under the associated event conditions. (4) A set of displays and controls located in the main control room should be provided for manual, system-level actuation of critical safety functions and monitoring of parameters that support the safety functions. The displays and controls should be independent and diverse from the safety computer system identified in Items (1) and (3) above. Applicability - RTS, ESFAS, control systems, diverse I&C systems, and supporting data communications systems in plants using digital computer- based RTS or ESFAS. Review Methods - SRP BTP 7-19, “Guidance for Evaluation of Diversity and Defense-in-Depth in Digital Computer-Based Instrumentation and Control Systems,” provides guidance for the evaluation of compliance with the SECY/SRM. SRP Sections 7.7 and 7.8 provide guidance for the review of control system and diverse I&C system features that are credited as nonsafety diverse means of protecting against common-cause failure within the safety systems. (b) Item II.T, “Control Room Annunciator (Alarm) Reliability,” of SRM on SECY-93-087, “Policy, Technical, and Licensing Issues Pertaining to Evolutionary and Advanced