Document: NUREG-0800
Document ID: cd35e91a-3d44-430c-9102-2c8a74c133ab
Document Type: srp
Title: SAFE SHUTDOWN SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1602/ML16020A086.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.4
CFR Part: 
CFR Title: 

Content:
sion 6 – August 2016 or licensee’s commitment regarding these design criteria. For computer-based safe shutdown systems, the guidance is provided by IEEE Std 7-4.3.2 as endorsed by RG 1.152. These procedures are detailed in SRP Appendix 7.1-B for IEEE Std 279- 1971, SRP Appendix 7.1-C for IEEE Std 603-1991, and SRP Appendix 7.1-D for IEEE Std 7-4.3.2. SRP Appendices 7.1-B and 7.1-C discuss the requirements of IEEE Std 279-1971 and IEEE Std 603-1991, respectively, and how they are used in the review of safe shutdown systems. SRP Appendix 7.1-D discusses the criteria of IEEE Std 7-4.3.2 and how they are used in the review of safe shutdown systems. Although the primary emphasis is on the equipment comprising the safe shutdown systems, the reviewer should consider the safe shutdown functions at the system level. The safe shutdown systems design should be compatible with the SAR Chapter 15 design bases accident analyses. It is not sufficient to evaluate the adequacy of the safe shutdown systems only on the basis that the design meets the specific requirements of IEEE Std 279-1971 or IEEE Std 603-1991. Major portions of the systems required for safe shutdown are also used as ESF systems, as discussed in SRP Section 7.3, “Engineered Safety Features Systems.” Therefore, the review under this SRP section includes those aspects of ESF systems that are unique to safe shutdown in addition to those systems required for safe shutdown, that are not classified as ESF systems. The safe shutdown systems review should address the topics identified as applicable by SRP Table 7-1. SRP Appendix 7.1-A describes review methods for each topic. Major design considerations that should be emphasized in the review of I&C for the safe shutdown systems are identified below. A. Independence - See SRP Appendix 7.1-B, Subsections 4.6 and 4.7 and SRP Appendix 7.1-C, Subsections 5.6 and 6.3. B. Use of digital systems, - See SRP Appendix 7.0-A, “Review Process for Digital Instrumentation and