Document: NUREG-0800
Document ID: d52a97d0-a519-4817-9ad6-64d94c9518af
Document Type: srp
Title: DATA COMMUNICATION SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159B177.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.9
CFR Part: 
CFR Title: 

Content:
he instrumentation setpoints (refer to RG 1.105, “Setpoints for Safety-Related Instrumentation,” and SRP BTP 7-12). Data rates, data bandwidths, and data precision requirements for normal and off- normal operation, including the impact of environmental extremes, should be reviewed. There should be sufficient excess capacity margins to accommodate likely future increases in DCS demands or software or hardware changes to equipment attached to the DCS. The error performance should be specified. Vendor test data and in situ test results should be reviewed to verify the performance. Analytical justifications of DCS capacity should be reviewed for correctness. The interfaces with other DCSs or other parts of the I&C system should be reviewed to verify compatibility. • Reliability - The potential hazards to the DCS and from the DCS should be reviewed. Unneeded but included DCS functions should be reviewed to ensure that they cannot be inadvertently activated and thereby prevent operation of the safety functions. The effects of error detection and recovery should be reviewed. Error detection should be at least as good as four byte cyclic redundancy check (CRC). The effects of DCS equipment malfunction or failure that generates 7.9-7 Draft Revision 6 - August 2015 erroneous signals, either in content or rate, should be examined. Corrupted messages (missing or corrupted packets), missing messages and duplicate messages should be detected and repaired. The reviewer should determine that the operating history of the DCS in similar applications is known and that it has been satisfactory. The reviewer should verify the existence and quality of maintenance and operator documentation and ensure that appropriate training has been or will be performed. The DCS should be designed to support self- testing and surveillance testing (refer to SRP BTP 7-17). • Time coherency of data - Methods to ensure the correct sequence of data packets at receiving DCS nodes should be reviewed.