Document: NUREG-0800
Document ID: b6428ab0-2037-4bac-9b93-b46af9f2fdfb
Document Type: srp
Title: DATA COMMUNICATION SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0706/ML070650036.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.9
CFR Part: 
CFR Title: 

Content:
d system. • System testing and inoperable surveillance - See SRP Appendix 7.1-B, subsections 4.9, 4.10, and 4.13 or SRP Appendix 7.1-C, subsections 5.7, 6.5, and 5.8. Insofar as bypass or deliberate inoperability of a DCS may induce the same condition on the system of which it is a part, the review should confirm that the bypassed and inoperable indications for DCSs are consistent with those of the systems of which they are part. • Protocols - The actual protocol functions needed to perform the safety mission should be determined. Protocols proposed for use, whether standard or proprietary, should be analyzed for hazards and performance deficits posed by unneeded functionality and complication. Additional guidance on protocols may be found in NUREG/CR-6082. • EMI/RFI susceptibility - See SRP Appendix 7.1-B, subsection 4.4, or SRP Appendix 7.1-C, subsection 5.4. The review should confirm that data communication media do not present a fault propagation path for environmental effects, such as high-energy electrical faults or lightning, from one redundant portion of a system to another or from 7.9-8 Revision 5 - March 2007 another system to a safety system. (Refer to Regulatory Guide 1.180, “Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety-Related Instrumentation and Control Systems,” for implementation and testing practices to establish electromagnetic compatibility and to Regulatory Guide 1.204, “Guidelines for Lightning Protection of Nuclear Power Plants,” for grounding and surge protection methods to provide lightning protection.) Fiber optics typically offer resistance to such effects but have other attributes that prevent universal acceptability. For example, if the fiber-optic medium may be subject to radiation, fiber that does not become opaque or brittle under irradiation should be specified, or there should be a defined replacement schedule. NUREG/CR-6082 compares the qualities of optical and conductive media