Document: NRC Regulatory Guide
Document ID: 82021804-a487-471b-a76c-095315525b53
Document Type: regulatory_guide
Title: Guidelines for Evaluating Electromagnetic and Radio-Frequency Interference in Safety-Related Instrumentation and Control Systems (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1628/ML16281A531.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.180
CFR Part: 
CFR Title: 

Content:
operating envelopes. To ensure that the operating envelopes are being used properly, equipment should be tested in a physical configuration that is representative of its actual installation. However, rather than requiring that every variation of cabinet configuration be tested, testing should be performed on bounding configuration(s) that reasonably represent the worst-case interference exposure and emissions conditions. For example, a sparse configuration of modules in a cabinet might represent the bounding interference exposure condition (e.g., limited self-shielding among cards) for susceptibility testing. Conversely, a fully loaded configuration of modules in a cabinet might represent the bounding emissions condition for emissions testing. Therefore, testing should be performed with the equipment under test configured in a bounding configuration for the phenomena of interest (e.g., conducted or radiated emissions, conducted or radiated susceptibility, and surge). A justification that the tested configuration reasonably bounds the expected worst case should be provided as part of the test plan to document the basis for the configuration. The as-tested physical configuration of the safety-related I&C system should be documented as part of test results so that EMC-specific configuration considerations can be implemented as part of installation, maintained, and controlled. The design specifications that should be maintained and controlled include wire and cable separations, shielding techniques, shielded enclosure integrity, DG-1333, Page 9 apertures, gasketing, grounding techniques, EMI/RFI filters, circuit board layouts, and the values of other design parameters that may impact the EMC qualification testing results. The equipment being tested should be in its normal mode of operation (i.e., performing its intended function) during the testing. For software-based systems, the system should have functioning software and diagnostics that are representative of those