Document: NUREG-0800
Document ID: dc63e8aa-2a74-4078-9e19-9a26ed1b4d8c
Document Type: srp
Title: Revision 6 – July 2012
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1105/ML110550791.pdf
Revision Date: 2023-06
Chapter: 7
Section ID: 7
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CFR Title: 

Content:
ssessment. (Coordination with the organization responsible for the review of reactor systems is necessary in reviewing these analyses.) 4.6 Identification of Alternative Mitigation Capability For each DBE, alternate mitigation actuation functions that will prevent or mitigate core damage and unacceptable release of radioactivity should be identified. When a CCF is compensated by a different automatic function, a basis should be provided that demonstrates that the different function constitutes adequate mitigation for the conditions of the event. When operator action is cited as the diverse means for response to an event, the applicant should demonstrate that adequate information (indication), appropriate operator training, and sufficient time for operator action are available in accordance with Appendix 18-A of SRP Chapter 18. Note: As the difference between Time Available and Time Required for operator action is a measure of the safety margin and as it decreases, uncertainty in the estimate of the difference between these times should be appropriately considered. This uncertainty could reduce the level of assurance and potentially invalidate a conclusion that operators can perform the action reliably within the time available. For complex situations and for actions with limited margin, such as less than 30 minutes between time available and time required, a more focused staff review will be performed. 4.7 Justification for Not Correcting Specific Vulnerabilities If any identified vulnerabilities are not addressed by design modification, refined analyses, or provision of alternate trip, initiation, or mitigation capability, justification should be provided. C. REFERENCES 1. DI&C-ISG-02, “Task Working Group #2: Diversity and Defense-in-Depth Issues Interim Staff Guidance,” Revision 2, USNRC, June 5, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML091590268). 2. NUREG-0800, SRP Chapter 18, Appendix 18-A, “Crediting Manual Operator