Document: NUREG-0800
Document ID: 96afb1d6-6ce9-41e4-b4ec-1fc7747bc0b2
Document Type: srp
Title: Revision 8 – January 2021
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2033/ML20339A647.pdf
Revision Date: 2023-05
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
– using alternative methods (Section B.3.1.3) – for low-safety-significance SSCs, using a qualitative assessment and failure analysis (Section B.3.1.4) • The applicant mitigated consequences of CCF vulnerabilities using one or more of the design techniques below: – crediting existing systems (Section B.3.2.1) – crediting manual operator actions (Section B.3.2.2) – crediting a new diverse system (Section B.3.2.3) • The applicant analyzed consequences of CCF vulnerabilities and found them to remain within the acceptance criteria defined in the FSAR or the LAR for the limiting events applicable to the proposed DI&C system or component (Section B.3.3) If the applicant used multiple strategies to address CCF vulnerabilities in different portions of a system, then the reviewer should evaluate the applicant’s analysis of the CCF vulnerabilities in each portion and identify how each method was applied. For example, in one portion of the system, the applicant might eliminate a CCF from further consideration, while in another portion, the applicant might mitigate the CCF vulnerability using diverse I&C systems. Spurious Operation as a Result of Common-Cause Failure The evaluation of potential spurious operations is an important part of the overall D3 assessment for a proposed DI&C system to ensure that spurious operations do not lead to events with unacceptable consequences. Although a spurious operation is not always anticipated, it can be detected because this type of failure is normally self-announcing through instrumentation on the actuated system. However, in some circumstances a spurious operation may not occur until a particular signal or set of signals is present. In these cases, rather than occurring immediately upon system startup, the spurious operation would occur only under certain plant conditions. Such a spurious operation is still self-announcing (by the actuated system), even if failure did not occur on initial test or BTP 7-19-18 Revision 8