Document: NUREG-0800
Document ID: f2ddec6c-0cce-4223-b813-233678ee07d0
Document Type: srp
Title: DIVERSE INSTRUMENTATION AND CONTROL SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1515/ML15159B171.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7.8
CFR Part: 
CFR Title: 

Content:
s and components. • System testing and surveillance - The applicant or licensee should identify the test, maintenance, surveillance, and calibration procedures. These provisions should be consistent with the guidance of Generic Letter 85-06. The ATWS mitigation system should be testable at power (up to, but not necessarily including, the final actuation device). • Use of digital systems - See Appendix 7.0-A, Appendix 7.1-D, and BTPs 7-14, 7-17, 7-18, 7-19, and 7-21. • Power supply availability - The reviewer should confirm with the organization responsible for the review of power systems that power sources will be available during and following a loss of offsite power. • Environmental qualification - The diverse I&C system equipment as installed should be qualified for the environment that could exist during the events for which the equipment is assumed to respond. • System status - Information should be available in the control room to indicate the operation of the diverse I&C systems. This aspect of the review may involve considerations included in emergency operating procedures. • Independence from the protection systems - Diverse actuation systems functions should be independent and diverse from the RTS and ESFAS. ATWS mitigation systems should be diverse from the RTS. For ATWS mitigation systems, 10 CFR 50.62 requires diversity from the sensor output to the final actuation device. See SRP Appendix 7.1-C, Subsections 5.6 and 6.3 and SRP Appendix 7.1-B, Subsection 4.6. • Potential for inadvertent actuation - The diverse I&C systems design should limit the potential for inadvertent actuation and challenges to safety systems. • Manual initiation capability - The ATWS mitigation systems and DAS should include the capability for initiation from the control room. • Completion of protective action - The ATWS mitigation logic and DAS should be designed such that, once initiated, the mitigation function will go to completion. • D3 analysis - The I&C