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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a plant’s overall defense in depth (e.g., by reducing independence). When evaluating integrated systems, the reviewer should focus primarily on NSR SSCs that are integrated with safety-related SSCs. This is because safety-related SSCs have particular regulatory requirements (e.g., for independence and quality) that separately address CCF vulnerabilities in integrated systems. A secondary focus should be on integration of NSR SSCs that can directly or indirectly affect reactivity (e.g., an NSR rod control system). In some cases, an NSR system may be susceptible to failures not analyzed in the design bases. The reviewer should consider whether a CCF of an integrated NSR DI&C system or platform (e.g., a single platform controlling multiple NSR system functions) could result in spurious operation that would have unacceptable consequences. The reviewer should also consider the level of integration between safety and NSR systems as a potential vulnerability to be addressed in the 11 Spurious operations addressed “within the design basis” include spurious operations resulting from single failures (including cascading effects) or single malfunctions. Consistent with regulatory requirements such as those of GDC 25 or those incorporated by reference in 10 CFR 50.55a(h) (namely, IEEE Std 279-1971 or IEEE Std 603-1991), spurious operations resulting from single failures and single malfunctions are expected during the lifetime of the plant and are addressed as part of the design basis. 12 The NRC staff is aware that the term “highly integrated” is sometimes used to refer to the special case of safety systems integrated with NSR systems. This BTP does not use that term. BTP 7-19-19 Revision 8 – January 2021 application.13 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