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
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“common-cause failure” because it better characterizes this type of failure. BTP 7-19-7 Revision 8 – January 2021 determines what portions of a design need additional D3 measures to address such failures. • NUREG/CR-7007, “Diversity Strategies for Nuclear Power Plant Instrumentation and Control Systems,” issued December 2008, provides diversity strategies to mitigate CCF vulnerabilities in a safety-related system for which a D3 assessment has shown a need for greater diversity. NUREG/CR-7007 identifies and develops a baseline set of diversity criteria that may be appropriate for addressing potential vulnerabilities to CCFs. While this NUREG describes a method for quantitatively assessing the amount of diversity in a system, this method has not been benchmarked and should not be used as the sole basis for justifying adequate diversity. • SECY-93-087, dated April 2, 1993, Item II.Q, as clarified by SRM-SECY-93-087, Item 18, describes the NRC position on defense against potential common-mode failures in DI&C systems. • SECY-18-0090, “Plan for Addressing Common Cause Failure in Digital Instrumentation and Controls,” dated September 12, 2018, describes the NRC staff’s plan to clarify the guidance for evaluating and addressing potential CCFs of DI&C systems. • Generic Letter (GL) 85-06, “Quality Assurance Guidance for ATWS Equipment That is Not Safety-Related,” dated April 16, 1985, provides quality assurance guidance for anticipated transient without scram (ATWS) equipment that is not safety related (NSR). GL 85-06 describes methods that may be used to establish quality assurance measures for equipment that is NSR and credited for providing the diverse means to mitigate potential CCFs. • RG 1.62, “Manual Initiation of Protective Actions,” describes a method that the staff considers acceptable for use in complying with the NRC’s regulations concerning the means for manual initiation of protective actions provided (1) by otherwise