Document: NUREG-0800
Document ID: 00a272ef-67f0-4667-9a5b-6f9c9490ef5b
Document Type: srp
Title: CONTROL SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1602/ML16020A095.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.7
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confirm that I&C systems include environmental control as necessary to protect equipment from environmental extremes. This would include, for example, heat tracing of safety instruments and instrument sensing lines as discussed in RG 1.151, “Instrument Sensing Lines,” and cabinet cooling fans. • Use of digital systems - To minimize the potential for control system failures that could challenge safety systems, control system software should be developed using a structured process similar to that applied to safety system software. Elements of the review process may be tailored to account for the lower safety significance of control system software. Refer to SRP Appendix 7.0-A, “Review Process for Digital Instrumentation and Control Systems,” and SRP Appendix 7.1-D for guidance on digital system review. 7.7-7 Revision 6 - August 2016 • Independence - The independence of safety system functions from the control system should be verified. See SRP Appendix 7.1-B, Subsection 4.6, and SRP Appendix 7.1-C, Subsections 5.6 and 6.3. • Diversity and Defense-in-Depth - Control system elements credited in the diversity and defense-in-depth analysis (see BTP 7-19) should be reviewed using the criteria for diverse I&C systems described in SRP Section 7.8. • Potential for inadvertent actuation - The control systems design should limit the potential for inadvertent actuation and challenges to safety systems. • Control of access - Physical and electronic access to digital computer-based control system software and data should be controlled to prevent changes by unauthorized personnel. Control should address access via network connections and via maintenance equipment. 2. For review of a DC application, the reviewer should follow the above procedures to verify that the design, including requirements and restrictions (e.g., interface requirements and site parameters), set forth in the final safety analysis report (FSAR) meets the acceptance criteria. DCs have referred