Document: NUREG-0800
Document ID: 94ab38ac-ddfc-4ba1-ae38-bc25ffa6e976
Document Type: srp
Title: – 15.4.5
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070716.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.4
CFR Part: 
CFR Title: 

Content:
by ensuring that the minimum departure from nucleate boiling ratio (DNBR) remains above the 95/95 DNBR 20 limit for PWRs and the critical power ratio (CPR) remains above the minimum 21 critical power ratio (MCPR) safety limit for BWRs, based on acceptable 22 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) An incident of moderate frequency, in combination with any single active component failure or single operator error, shall be considered and is an event for which an estimate of the number of potential fuel failures shall be provided for radiological dose calculations. For such accidents, fuel failure must be assumed for all rods for which the DNBR or CPR falls below those values cited above for cladding integrity, unless it can be shown, based on an acceptable fuel damage mode (see SRP Section 4.2), that fewer failures occur. There shall be no loss of function of any fission product barrier other than the fuel cladding. (e) 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 transientsAOOs addressed in this SRP section. (f) The most limiting plant systems single failure, as defined in the "Definitions and Explanations" of Appendix A to 10 CFR Part 50, shall be identified and assumed in the analysis and should satisfy the guidance stated in Regulatory Guide 1.53. The applicant's analysis of the most limiting transientsAOOs should be performed using an acceptable model. If analytical methods which have not been approved are proposed by the applicant, they are evaluated by the staff for acceptability. 15.4.4-5 DRAFT Rev. 2 - April 1996 The values of parameters used in the analytical model are to be suitably conservative. The following values are considered acceptable: a. Initial power level is rated output (licensed core thermal power)