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:
the CCF meet the acceptance criteria defined in the FSAR or the LAR for the limiting events applicable to the proposed system or component. If an existing system is credited, then the reviewer should verify that the applicant performed an analysis demonstrating that the credited system and the proposed system are not both vulnerable to the same CCF. The reviewer should verify that the applicant considered how the existing system is credited in the facility’s licensing basis and described in the existing system’s documentation (FSAR, detailed design documents, etc.). Among other things, the reviewer should consider whether BTP 7-19-25 Revision 8 – January 2021 the applicant has appropriately accounted for any unique system design attributes and requirements and potential interconnectivities to other systems. The reviewer should pay particular attention to whether there may be interconnectivities the LAR has not accounted for that may result in the existing system being subject to the same CCF as the proposed DI&C system or component. The reviewer should verify that the application has identified all the features of the existing system that are relevant to demonstrating diversity. In addition, if crediting an existing system could affect the facility’s existing licensing basis, then the reviewer should verify that the LAR addresses how the existing system functions would be credited and justified in a revised licensing basis. The credited existing system may be an NSR system, as long as it is of sufficient quality and can reliably perform the credited functions under the associated event conditions. If the applicant credits NSR systems that are in continuous use (e.g., the normal reactor coolant system inventory control system or the normal steam generator level control system), these systems need not meet augmented quality standards. However, if the applicant credits NSR systems that are not in continuous use (i.e., that are normally in standby mode), then