Document: NUREG-0800
Document ID: 2bca792d-0e88-4e2d-b437-be572ed57a48
Document Type: srp
Title: REVIEW OF TRANSIENT AND ACCIDENT ANALYSIS METHODS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0708/ML070820123.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.0.2
CFR Part: 
CFR Title: 

Content:
ons of all important experimental measurements with the code predictions in order to expose possible cases of compensating errors. Such errors may result in good predictions of key parameters, derived from poor predictions of contributing parameters. These cases are often indicative of tuning the code to an integral experiment. One example of this is described in NUREG/CR-5249, in which key parameters, namely large-break LOCA (LBLOCA) reflood peak cladding temperatures were predicted well, even though an important contributing factor, the core void fraction during reflood, was not predicted accurately. In the case of LOCA evaluation models, specific assessment test cases are required in order to meet the requirements of Appendix K to 10 CFR Part 50. Specific test cases are also specified in the TMI action items for PWR small- break LOCA (SBLOCA) evaluation models. The reviewers should confirm that these assessments have been performed where applicable. The reviewers should refer to published literature for sources of assessment data for specific phenomena, accident scenarios, and plant types. These include the ECCS Compendium, NEA validation data documents, and International Standard problems. E. Uncertainty Analysis. The reviewers should confirm that the method for calculating uncertainty contains all important sources of uncertainty and that a sample uncertainty calculation for a prototypical plant gives a reasonable estimate of the calculation uncertainty. The reviewers should confirm that the accident scenario identification process was used in identifying the important sources of uncertainty. The reviewers should confirm that sources of code uncertainty have been addressed. These include uncertainties in theoretical models or closure relationships determined from comparison to separate effects tests, uncertainties due to scaling of the basic models and closure relationships, and uncertainties due to plant nodalization and solution techniques. The reviewers can