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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ould consider whether the applicant’s D3 assessment describes the diversity of the proposed DI&C system or component across blocks. When considering the effects of a postulated CCF, the reviewer may assume that the diverse blocks function as designed. This includes blocks that act to prevent or mitigate consequences of the CCF under consideration. 6.2 Documentation of Assumptions The reviewer should verify that the application documents and justifies any assumptions made to compensate for missing information in the design description materials or to explain interpretations of the analysis guidelines applied to the system. BTP 7-19-33 Revision 8 – January 2021 6.3 Identification of Alternate Trip or Initiation Sequences The reviewer should verify that the applicant’s assessment includes thermal-hydraulic analyses of the sequence of events that would occur if the primary trip channel failed to trip the reactor or actuate ESFs. The thermal-hydraulic analyses may use realistic or conservative (design-basis) assumptions. When evaluating these analyses, the reviewer should coordinate with the NRC staff organization responsible for the review of reactor systems. 6.4 Identification of Alternative Mitigation Capability For each DBE, the reviewer should verify that the applicant has identified alternative mitigation actuation functions that will prevent or mitigate core damage and unacceptable release of radioactivity. If a potential CCF in an automatic or manual function credited in the plant accident analysis is compensated for by a different automatic or manual function, the applicant should provide a basis demonstrating that the different function constitutes adequate mitigation in the event conditions. If the application cites a manual operator action as a diverse means for responding to an event, the reviewer should verify that the applicant’s HFE analysis and assessment demonstrates (e.g., through the process in SRP Chapter 18) that this action is both feasible