Document: NUREG-0800
Document ID: 18405759-3ae6-4408-b6ab-7b3ca11fcd9f
Document Type: srp
Title: SAFE SHUTDOWN SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550085.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.4
CFR Part: 
CFR Title: 

Content:
safe shutdown with respect to fire protection. Specifically, fire damage limits as they impact safe shutdown have been established therein. These limits do not require consideration of an additional, random, single failure in the evaluation of the capability to safely shut down as a consequence of fire. The evaluation of conformance to Regulatory Guide 1.189 is addressed in SRP Section 9.5.1. Therefore, the application of the single-failure criterion to remote shutdown is applicable only to other events that could cause the control room to become uninhabitable. These events would not result in consequential damage or unavailability of systems required for safe shutdown. 7.4-6 Revision 5 - March 2007 Major portions of the systems required for safe shutdown are also used as ESF systems, as discussed in SRP Section 7.3. 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 and SRP Appendix 7.1-D. C. Periodic testing - See SRP Appendix 7.1-B subsection 4.10 and SRP Appendix 7.1-C subsections 5.7 and 6.5. D. Remote shutdown capability1 - Plant designs should provide for control in locations removed from the main control room that may be used for manual control and alignment of safe shutdown system equipment needed to achieve and maintain hot and cold shutdown. This control equipment should be capable of operating independently of (i.e., without interaction with) the