Document: NUREG-0800
Document ID: 1877a6e5-f5a2-4394-bd63-c323831e96d0
Document Type: srp
Title: INTRODUCTION - TRANSIENT AND ACCIDENT ANALYSES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2231/ML22319A149.pdf
Revision Date: 2023-07
Chapter: 15
Section ID: 15.0
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Content:
rt-term.5 Additionally, the events should be evaluated into the long term to demonstrate the reactor will remain in a safe and stable condition beyond 72 hours. The reviewer should ensure there remain no degrading or transitory phenomena, and all figures of merit have a favorable trend. Transition to recovery or long-term support from non-safety-related systems, structures, and components (SSCs) is outside the scope of the staff’s Chapter 15 review. Post-72- hour operator actions, defense-in-depth, and regulatory treatment of non-safety systems (RTNSS) is evaluated as part of the staff’s review of Chapter 19 or corresponding system section. 3. Plant Characteristics Considered in the Safety Analysis. The reviewer ensures that the application contains the key plant parameters considered in the safety analysis (e.g., core power, core inlet temperature, reactor system pressure, core flow, axial and radial power distribution, fuel and moderator temperature coefficient, void coefficient, reactor kinetics parameters, available shutdown rod worth, and control rod insertion characteristics). The reviewer checks that the range of values for plant parameters is acceptable, consistent with technical specifications, and sufficiently broad to cover the predicted fuel cycle ranges, to the extent practicable, based on the fuel design and acceptable analytical methodology at the time of the application. The reviewer also ensures that the application specifies the permitted fluctuations and uncertainties associated with reactor system parameters and assumes the appropriate conditions, within the operating band, as initial conditions for transient analysis. 4. Assumed Protection and Safety Systems Actions. The reviewer ensures that the application lists the settings of all the protection and safety systems functions that are 5 For an example, see SECY-18-0099, “NuScale Power Exemption Request from 10 CFR Part 50, Appendix A, General Design Criterion 27, ‘Combined Reactivity