Document: NUREG-0800
Document ID: 40c0bbb1-aed6-41a9-b8ac-ca483637a639
Document Type: srp
Title: - 15.4.5-4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550007.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.4
CFR Part: 
CFR Title: 

Content:
Revision 2 - March 2007 Using the ANS standards as guidance, the specific criteria necessary to meet the relevant requirements of the regulations identified above for incidents of moderate frequency are as follows: A. Pressure in the reactor coolant and main steam systems should be maintained below 110% of the design values. B. Fuel-cladding integrity shall be maintained by ensuring that the minimum departure from nucleate boiling ratio (DNBR) remains above the 95% probability/95% confidence DNBR limit for PWRs and the critical power ratio (CPR) remains above the minimum critical power ratio (MCPR) safety limit for BWRs, based on acceptable correlations (see SRP Section 4.4). C. An incident of moderate frequency should not generate a more serious plant condition without other faults occurring independently. D. The requirements stated in Regulatory Guide 1.105, "Instrument Spans and Setpoints," are used with regard to their impact on the plant response to the type of AOOs addressed in this SRP section. E. The most limiting plant systems single failure, as defined in the "Definitions and Explanations" of Appendix A to 10 CFR 50, shall be identified and assumed in the analysis and should satisfy the guidance stated in Regulatory Guide 1.53. F. The guidance provided in SECY 77-439, SECY 94-084 and RG 1.206 with respect to the consideration of the performance of non-safety related systems during transients and accidents, as well as the consideration of single failures of active and passive systems (especially as they relate to the performance of check valves in passive systems), must be evaluated and verified. The applicant's analysis of the most limiting AOOs should be performed using an acceptable model. If analytical methods that have not been approved are proposed by the applicant, they are evaluated by the staff for acceptability. The values of parameters used in the analytical model are to be suitably conservative. The following values are considered acceptable: 1.