Document: NUREG-0800
Document ID: 56298a3a-bad0-4f4d-91c4-5fc5c1817434
Document Type: srp
Title: INTERLOCK SYSTEMS IMPORTANT TO SAFETY
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0704/ML070460348.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.6
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Content:
the SRP criteria provide an acceptable method of complying with the relevant NRC requirements identified in Subsection II. SRP Section 7.1 describes the general procedures to be followed in reviewing any instrumentation and control system. This part of SRP Section 7.6 highlights specific topics that should be emphasized in the interlock systems review. 1. The review should include an evaluation of the interlock system design against the guidance of IEEE Std 603-1991 or IEEE Std 279-1971, depending on the applicant/licensee’s commitment regarding these design criteria. For computer-based interlock systems, the guidance is provided by IEEE Std 7-4.3.2-2003 as endorsed by Regulatory Guide 1.152, Revision 2. 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 7-4.3.2-2003. SRP Appendices 7.1-B and 7.1-C discuss IEEE Std 279-1971 and IEEE Std 603-1991, respectively, and how they are used in the review of the interlock systems. SRP Appendix 7.1-D discusses the criteria of IEEE Std 7-4.3.2-2003 and how they are used in the review of interlocks. Although the primary emphasis is on the equipment comprising the interlock systems, the reviewer should consider the interlock functions at the system level. The interlock systems design should be compatible with the SAR Chapter 15 design bases accident analyses. It is not sufficient to evaluate the adequacy of the interlock systems only on the basis of the design’s meeting the specific requirements of IEEE Std 279-1971 or IEEE Std 603-1991. The interlock systems review should address the applicable topics identified in 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 the interlock systems are identified below. A. Single-failure criterion - See SRP Appendix 7.1-B subsection 4.2 or SRP Appendix 7.1-C subsection 5.1. B. Quality of