Document: NUREG-0800
Document ID: 2717fe7f-71fd-4f1e-bd08-7685b24763ba
Document Type: srp
Title: Standard Review Plans are prepared for the guidance of the Office of Nuclear Reactor Regulation staff responsible for th
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0301/ML030160606.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15
CFR Part: 
CFR Title: 

Content:
model input parameters for plant operating conditions (e.g., accident initial conditions, set points, and boundary conditions). Calculation uncertainties are specific to a given licensing calculation. Therefore, it is sometimes acceptable to use bounding values in the licensing calculation for these types of uncertainties. The reviewers should confirm that the uncertainties in the experimental data base have been addressed. These uncertainties arise from such items as measurement errors and experimental distortions. For separate effects tests and integral effects tests, the reviewers should confirm that the differences between calculated results and experimental data for important phenomena have been quantified for bias and deviation. The reviewers should confirm that data sets and correlations with experimental 12 uncertainties that are too large when compared to the requirements for evaluation model assessment are not used. When the code is used in a licensing calculation, the reviewers should confirm that the combined code and application uncertainty is less than the design margin for the safety parameter of interest in the calculation. For best estimate LOCA analyses, uncertainty determination description and guidance are described in NUREG/CR-5249 [Ref. 4], Regulatory Guide 1.157, and in Appendix A to DG-1120 [Ref. 2]. In these examples, the uncertainty analyses discussed have the ultimate objective of providing a singular statement of uncertainty with respect to the 10 CFR 50.46 acceptance criteria. This singular uncertainty statement is accomplished when the individual uncertainty contributions are determined (see Regulatory Guide 1.157, Ref. 10). For other events, a complete uncertainty analysis is not required. However, in most cases the SRP guidance is to use “suitably conservative” input parameters. This suitability determination may involve a limited assessment of biases and uncertainties. The individual uncertainty (in terms of range and