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:
or eliminating the potential for CCFs from further consideration. 3.1.1 Use of Diversity within the Digital Instrumentation and Control System to Eliminate the Potential for Common-Cause Failures from Further Consideration Diversity within a DI&C system constitutes the use of different techniques, schemes, features, or additions to eliminate a CCF from further consideration. If diversity is used, then each portion of the system will have different potential latent design defects, so that a failure in one portion will not result in a failure in other portions. Diversity can be implemented in various ways, such as through the use of different technologies, algorithms, or logic; sensing devices; or actuation devices. However, diversity needs to be paired with independence from equipment performing the same function within the DI&C system; otherwise, the diverse means could be susceptible to the same CCF. The reviewer should determine whether the proposed system contains sufficient diversity to perform the safety function, including diversity within each safety division or among redundant safety divisions of a system. If so, then the potential CCF can be eliminated from further consideration. Acceptance Criteria for Use of Diversity within the Digital Instrumentation and Control System If the following acceptance criteria are met, the reviewer should conclude that the application provides adequate information on the use of diversity within the DI&C system to eliminate the potential CCF from further consideration: BTP 7-19-20 Revision 9 — May 2024 a. Each safety function to be achieved by the proposed design is shown to be independently achievable by each diverse portion in the DI&C system. Diversity between the different portions of the DI&C system is sufficient to account for potential spurious operation. b. The different portions of the DI&C system are sufficiently diverse to perform the safety function without relying on the performance of common components, and