Document: NUREG-0800
Document ID: ffa64ced-0841-46c1-aca6-e9696da65092
Document Type: srp
Title: of the SAR.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500493.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.3
CFR Part: 
CFR Title: 

Content:
Rev. 4 — June 1997 SRP 7.1-A-16 g. Criterion 21 — Protection System Reliability and Testability "The protection system shall be designed for high functional reliability and in-service testability commensurate with the safety functions to be performed. Redundancy and independence designed into the protection system shall be sufficient to assure that (1) no single failure results in loss of the protection function, and (2) removal from service of any component or channel does not result in loss of the required minimum redundancy unless the acceptable reliability of operation of the protection system can be otherwise demonstrated. The protection system shall be designed to permit periodic testing of its functioning when the reactor is in operation, including a capability to test channels independently to determine failures and losses of redundancy that may have occurred." Applicability — The protection systems, RTS, ESFAS, and supporting data communication systems. Review Methods — Review of compliance with GDC 21 should address the following characteristics described in ANSI/IEEE Std 279 and IEEE Std 603. SRP Appendix 7.1-B and Appendix 7.1-C discuss methods for review of these characteristics. Location of Review Guidance Topic Appendix 7.1-B Item Appendix 7.1-C Item Design basis reliability requirements and reliability determination methods 1 4 Single-failure criterion 3 6 Completion of protective action once initiated 17 7 and 25 Quality 4 8 System integrity 6 10 Physical, electrical, and communications independence 7 and 8 11 and 24 Capability for test and calibration 10 and 11 12 and 27 Indication of bypass 14 13 Control of access to safety system equipment 15 and 19 14 Repair and troubleshooting provisions 21 15 Identification of protection system equipment 22 16 Auxiliary features 6 17 Multi-unit stations 6 18 Human factors considerations 20 19 Reliability 2 20 Location of Review Guidance Topic Appendix 7.1-B Item Appendix 7.1-C Item Rev. 4 — June 1997