Document: NUREG-0800
Document ID: a9242e96-646c-405b-bcbe-0f249e45b75c
Document Type: srp
Title: Appendix 7-A
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0525/ML052500544.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
Appendix 7-A Rev. 4 — June 1997 BTP HICB-11-1 NEW Branch Technical Position HICB-11 Guidance on Application and Qualification of Isolation Devices A. Background This branch technical position (BTP) provides guidelines for reviewing the use of isolation devices in instrumentation and control systems. These acceptance guidelines are based on experience in the review of applicant/licensee submittals for electrical qualification and application of isolation devices in safety systems. The devices that provide isolation between safety and non-safety portions of power distribution systems are addressed in SRP Chapter 8. 1. Regulatory Basis 10 CFR 50.55a(h) requires in part that protection systems satisfy the criteria of ANSI/IEEE Std 279, "Criteria for Protection Systems for Nuclear Power Generating Stations," paragraph 4.7.2, "Isolation Devices." These criteria state that "the transmission of signals from protection system equipment for control system use shall be through isolation devices which shall be classified as part of the protection system...," and that "no credible failure at the output of an isolation device shall prevent the associated protection system channel from meeting the minimum performance requirements specified in the design bases." 10 CFR 50 Appendix A, General Design Criterion (GDC) 1, "Quality Standards and Records," requires in part that "structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed." GDC 1 also requires that "where generally recognized codes and standards are used, they shall be identified and evaluated to determine their applicability, adequacy, and sufficiency and shall be modified as necessary to assure a quality product in keeping with the required safety function." 10 CFR 50 Appendix B, Criterion III, "Design Control," requires in part that, "where a test program is used to verify the