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:
ions resulting from single failures and single malfunctions are expected during the lifetime of the plant and are addressed as part of the design basis. 9 See IEEE Std 603-1991. BTP 7-19-19 Revision 9 — May 2024 The NRC Staff’s Evaluation of Spurious Operation The reviewer should consider whether the D3 assessment addresses spurious operation resulting from CCF along with loss of function resulting from CCF. One important distinction between these two events is that, unlike loss of function, spurious operation is considered an initiating event only, that is, without a concurrent DBE for the purposes of this assessment. 3.1 Means to Eliminate the Potential for Common-Cause Failures from Further Consideration In a D3 assessment, the following methods can be used to eliminate a potential CCF from further consideration: (1) demonstration of adequate diversity within the DI&C system, (2) testing, and (3) alternative approaches within the application. In addition, for SSCs with lower or lowest safety significance, a qualitative assessment and failure analysis showing that the likelihood of failure is sufficiently low can be used to eliminate a CCF from further consideration. The reviewer should determine whether the application demonstrates that the use of these methods, alone or in any combination, meets the criteria in this BTP to eliminate the potential CCF from further consideration. Even if the applicant does not eliminate all CCF vulnerabilities from further consideration using these methods, the reviewer should consider whether there is any portion of the SSC for which the applicant has sufficiently reduced the likelihood of a CCF so that further evaluation is unnecessary for that portion of the SSC. The following sections discuss each of the acceptable methods for 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