Document: NUREG-0800
Document ID: fe8ec6c2-e960-404c-854f-55c77bde1672
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2400/ML24005A077.pdf
Revision Date: 2024-05
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
r the applicant used risk insights from site-specific PRAs, if available, to support its determination. The reviewer should confirm that the application documents the basis for the safety-significance determination, including any use of risk insights. The reviewer should also determine whether the use of risk insights is reasonable. System Interconnectivity System interconnectivity has the potential to introduce additional dependencies and CCF vulnerabilities. If there is interconnectivity, the system should be assessed using the methods appropriate for the SSC of most safety significance that is interconnected. The reviewer should consider whether the application includes a clear description of the proposed DI&C system that identifies (1) shared resources, (2) interconnection with other systems, and (3) whether a modification could reduce the redundancy, diversity, separation, or independence of systems described in the facility’s FSAR. Reductions in independence, separation, diversity, or redundancy can adversely affect a plant’s defense in depth. For data communication interconnectivity, the reviewer should verify that such interconnectivity does not adversely affect or degrade the safety-related system’s reliability or its capability to perform its safety functions. RG 1.152 provides, in part, guidance for data communication independence, control of access, and prioritization of control and protection systems sharing components. The reviewer should also determine whether the assessment of the most safety-significant SSCs considers the vulnerability to CCF resulting from system interconnectivity and the consequences of a CCF that could affect the proper operation of the interconnected systems. If the reactor trip or engineered safety feature initiation signal in such a system reaches the final actuation device only through the equipment that performs control functions, then the reviewer should determine whether all the SSCs in that pathway have been